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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..6833f05 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,3 @@ +* text=auto +*.txt text +*.md text diff --git a/3421-h.zip b/3421-h.zip Binary files differnew file mode 100644 index 0000000..34ba894 --- /dev/null +++ b/3421-h.zip diff --git a/3421-h/3421-h.htm b/3421-h/3421-h.htm new file mode 100644 index 0000000..4a070e5 --- /dev/null +++ b/3421-h/3421-h.htm @@ -0,0 +1,10504 @@ +<?xml version="1.0" encoding="us-ascii"?> + +<!DOCTYPE html + PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd" > + +<html xmlns="http://www.w3.org/1999/xhtml" lang="en"> + <head> + <title> + Bramble-bees and Others, by J. Henri Fabre + </title> + <style type="text/css" xml:space="preserve"> + + body { margin:5%; background:#faebd0; text-align:justify} + P { text-indent: 1em; margin-top: .25em; margin-bottom: .25em; } + H1,H2,H3,H4,H5,H6 { text-align: center; margin-left: 15%; margin-right: 15%; } + hr { width: 50%; text-align: center;} + .foot { margin-left: 20%; margin-right: 20%; text-align: justify; text-indent: -3em; font-size: 90%; } + blockquote {font-size: 97%; font-style: italic; margin-left: 10%; margin-right: 10%;} + .mynote {background-color: #DDE; color: #000; padding: .5em; margin-left: 10%; margin-right: 10%; font-family: sans-serif; font-size: 95%;} + .toc { margin-left: 10%; margin-bottom: .75em;} + .toc2 { margin-left: 20%;} + div.fig { display:block; margin:0 auto; text-align:center; } + div.middle { margin-left: 20%; margin-right: 20%; text-align: justify; } + .figleft {float: left; margin-left: 0%; margin-right: 1%;} + .figright {float: right; margin-right: 0%; margin-left: 1%;} + .pagenum {display:inline; font-size: 70%; font-style:normal; + margin: 0; padding: 0; position: absolute; right: 1%; + text-align: right;} + pre { font-style: italic; font-size: 90%; margin-left: 10%;} + +</style> + </head> + <body> +<pre xml:space="preserve"> + +The Project Gutenberg EBook of Bramble-bees and Others, by J. Henri Fabre + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: Bramble-bees and Others + +Author: J. Henri Fabre + +Release Date: January 17, 2009 [EBook #3421] +Last Updated: January 22, 2013 + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK BRAMBLE-BEES AND OTHERS *** + + + + +Produced by Sue Asscher, and David Widger + + + + + + +</pre> + <p> + <br /><br /> + </p> + <h1> + BRAMBLE-BEES AND OTHERS + </h1> + <p> + <br /> + </p> + <h2> + by J. HENRI FABRE + </h2> + <p> + <br /><br /> + </p> + <h3> + TRANSLATED BY ALEXANDER TEIXEIRA DE MATTOS, F.Z.S. + </h3> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> <a name="link2H_4_0001" id="link2H_4_0001"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h3> + TRANSLATOR'S NOTE. + </h3> + <p> + In this volume I have collected all the essays on Wild Bees scattered + through the "Souvenirs entomologiques," with the exception of those on the + Chalicodomae, or Mason-bees proper, which form the contents of a separate + volume entitled "The Mason-bees." + </p> + <p> + The first two essays on the Halicti (Chapters 12 and 13) have already + appeared in an abbreviated form in "The Life and Love of the Insect," + translated by myself and published by Messrs. A. & C. Black (in + America by the Macmillan Co.) in 1911. With the greatest courtesy and + kindness, Messrs. Black have given me their permission to include these + two chapters in the present volume; they did so without fee or + consideration of any kind, merely on my representation that it would be a + great pity if this uniform edition of Fabre's Works should be rendered + incomplete because certain essays formed part of volumes of extracts + previously published in this country. Their generosity is almost + unparalleled in my experience; and I wish to thank them publicly for it in + the name of the author, of the French publishers and of the English and + American publishers, as well as in my own. + </p> + <p> + Of the remaining chapters, one or two have appeared in the "English + Review" or other magazines; but most of them now see the light in English + for the first time. + </p> + <p> + I have once more, as in the case of "The Mason-bees," to thank Miss + Frances Rodwell for the help which she has given me in the work of + translation and research; and I am also grateful for much kind assistance + received from the staff of the Natural History Museum and from Mr. + Geoffrey Meade-Waldo in particular. + </p> + <p> + ALEXANDER TEIXEIRA DE MATTOS. + </p> + <p> + Chelsea, 1915. + </p> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> + </p> + <h2> + Contents + </h2> + <table summary="" style="margin-right: auto; margin-left: auto"> + <tr> + <td> + <a href="#link2HCH0001"> CHAPTER 1. </a> + </td> + <td> + BRAMBLE-DWELLERS. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0002"> CHAPTER 2. </a> + </td> + <td> + THE OSMIAE. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0003"> CHAPTER 3. </a> + </td> + <td> + THE DISTRIBUTION OF THE SEXES. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0004"> CHAPTER 4. </a> + </td> + <td> + THE MOTHER DECIDES THE SEX OF THE EGG. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0005"> CHAPTER 5. </a> + </td> + <td> + PERMUTATIONS OF SEX. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0006"> CHAPTER 6. </a> + </td> + <td> + INSTINCT AND DISCERNMENT. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0007"> CHAPTER 7. </a> + </td> + <td> + ECONOMY OF ENERGY. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0008"> CHAPTER 8. </a> + </td> + <td> + THE LEAF-CUTTERS. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0009"> CHAPTER 9. </a> + </td> + <td> + THE COTTON-BEES. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0010"> CHAPTER 10. </a> + </td> + <td> + THE RESIN-BEES. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0011"> CHAPTER 11. </a> + </td> + <td> + THE POISON OF THE BEE. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0012"> CHAPTER 12. </a> + </td> + <td> + THE HALICTI: A PARASITE. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0013"> CHAPTER 13. </a> + </td> + <td> + THE HALICTI: THE PORTRESS. + </td> + </tr> + <tr> + <td> + <a href="#link2HCH0014"> CHAPTER 14. </a> + </td> + <td> + THE HALICTI: PARTHENOGENESIS. + </td> + </tr> + <tr> + <td> + </td> + </tr> + </table> + <p> + <br /> <br /> + </p> + <hr /> + <p> + <br /> <br /> <a name="link2HCH0001" id="link2HCH0001"> + <!-- H2 anchor --> </a> + </p> + <h2> + CHAPTER 1. BRAMBLE-DWELLERS. + </h2> + <p> + The peasant, as he trims his hedge, whose riotous tangle threatens to + encroach upon the road, cuts the trailing stems of the bramble a foot or + two from the ground and leaves the root-stock, which soon dries up. These + bramble-stumps, sheltered and protected by the thorny brushwood, are in + great demand among a host of Hymenoptera who have families to settle. The + stump, when dry, offers to any one that knows how to use it a hygienic + dwelling, where there is no fear of damp from the sap; its soft and + abundant pith lends itself to easy work; and the top offers a weak spot + which makes it possible for the insect to reach the vein of least + resistance at once, without cutting away through the hard ligneous wall. + To many, therefore, of the Bee and Wasp tribe, whether honey-gatherers or + hunters, one of these dry stalks is a valuable discovery when its diameter + matches the size of its would-be inhabitants; and it is also an + interesting subject of study to the entomologist who, in the winter, + pruning-shears in hand, can gather in the hedgerows a faggot rich in small + industrial wonders. Visiting the bramble-bushes has long been one of my + favourite pastimes during the enforced leisure of the wintertime; and it + is seldom but some new discovery, some unexpected fact, makes up to me for + my torn fingers. + </p> + <p> + My list, which is still far from being complete, already numbers nearly + thirty species of bramble-dwellers in the neighbourhood of my house; other + observers, more assiduous than I, exploring another region and one + covering a wider range, have counted as many as fifty. I give at foot an + inventory of the species which I have noted. + </p> + <p> + (Bramble-dwelling insects in the neighbourhood of Serignan [Vaucluse]: + </p> +<pre xml:space="preserve"> + 1. MELLIFEROUS HYMENOPTERA. + Osmia tridentata, DUF. and PER. + Osmia detrita, PEREZ. + Anthidium scapulare, LATR. + Heriades rubicola, PEREZ. + Prosopis confusa, SCHENCK. + Ceratina chalcites, GERM. + Ceratina albilabris, FAB. + Ceratina callosa, FAB. + Ceratina coerulea, VILLERS. + + 2. HUNTING HYMENOPTERA. + Solenius vagus, FAB. (provisions, Diptera). + Solenius lapidarius, LEP. (provisions, Spiders?). + Cemonus unicolor, PANZ. (provisions, Plant-lice). + Psen atratus (provisions, Black Plant-lice). + Tripoxylon figulus, LIN. (provisions, Spiders). + A Pompilus, unknown (provisions, Spiders). + Odynerus delphinalis, GIRAUD. + + 3. PARASITICAL HYMENOPTERA. + A Leucopsis, unknown (parasite of Anthidium scapulare). + A small Scoliid, unknown (parasite of Solenius vagus). + Omalus auratus (parasite of various bramble-dwellers). + Cryptus bimaculatus, GRAV. (parasite of Osmia detrita). + Cryptus gyrator, DUF. (parasite of Tripoxylon figulus). + Ephialtes divinator, ROSSI (parasite of Cemonus unicolor). + Ephialtes mediator, GRAV. (parasite of Psen atratus). + Foenus pyrenaicus, GUERIN. + Euritoma rubicola, J. GIRAUD (parasite of Osmia detrita). + + 4. COLEOPTERA. + Zonitis mutica, FAB. (parasite of Osmia tridentata). +</pre> + <p> + Most of these insects have been submitted to a learned expert, Professor + Jean Perez, of Bordeaux. I take this opportunity of renewing my thanks for + his kindness in identifying them for me.—Author's Note.) + </p> + <p> + They include members of very diverse corporations. Some, more industrious + and equipped with better tools, remove the pith from the dry stem and thus + obtain a vertical cylindrical gallery, the length of which may be nearly a + cubit. This sheath is next divided, by partitions, into more or less + numerous storeys, each of which forms the cell of a larva. Others, less + well-endowed with strength and implements, avail themselves of the old + galleries of other insects, galleries that have been abandoned after + serving as a home for their builder's family. Their only work is to make + some slight repairs in the ruined tenement, to clear the channel of its + lumber, such as the remains of cocoons and the litter of shattered + ceilings, and lastly to build new partitions, either with a plaster made + of clay or with a concrete formed of pith-scrapings cemented with a drop + of saliva. + </p> + <p> + You can tell these borrowed dwellings by the unequal size of the storeys. + When the worker has herself bored the channel, she economizes her space: + she knows how costly it is. The cells, in that case, are all alike, the + proper size for the tenant, neither too large nor too small. In this box, + which has cost weeks of labour, the insect has to house the largest + possible number of larvae, while allotting the necessary amount of room to + each. Method in the superposition of the floors and economy of space are + here the absolute rule. + </p> + <p> + But there is evidence of waste when the insect makes use of a bramble + hollowed by another. This is the case with Tripoxylon figulus. To obtain + the store-rooms wherein to deposit her scanty stock of Spiders, she + divides her borrowed cylinder into very unequal cells, by means of slender + clay partitions. Some are a centimetre (.39 inch.—Translator's + Note.) deep, the proper size for the insect; others are as much as two + inches. These spacious rooms, out of all proportion to the occupier, + reveal the reckless extravagance of a casual proprietress whose + title-deeds have cost her nothing. + </p> + <p> + But, whether they be the original builders or labourers touching up the + work of others, they all alike have their parasites, who constitute the + third class of bramble-dwellers. These have neither galleries to excavate + nor victuals to provide; they lay their egg in a strange cell; and their + grub feeds either on the provisions of the lawful owner's larva or on that + larva itself. + </p> + <p> + At the head of this population, as regards both the finish and the + magnitude of the structure, stands the Three-pronged Osmia (Osmia + tridentata, DUF. and PER.), to whom this chapter shall be specially + devoted. Her gallery, which has the diameter of a lead pencil, sometimes + descends to a depth of twenty inches. It is at first almost exactly + cylindrical; but, in the course of the victualling, changes occur which + modify it slightly at geometrically determined distances. The work of + boring possesses no great interest. In the month of July, we see the + insect, perched on a bramble-stump, attack the pith and dig itself a well. + When this is deep enough, the Osmia goes down, tears off a few particles + of pith and comes up again to fling her load outside. This monotonous + labour continues until the Bee deems the gallery long enough, or until, as + often happens, she finds herself stopped by an impassable knot. + </p> + <p> + Next comes the ration of honey, the laying of the egg and the + partitioning, the last a delicate operation to which the insect proceeds + by degrees from the base to the top. At the bottom of the gallery, a pile + of honey is placed and an egg laid upon the pile; then a partition is + built to separate this cell from the next, for each larva must have its + special chamber, about a centimetre and a half (.58 inch.—Translator's + Note.) long, having no communication with the chambers adjoining. The + materials employed for this partition are bramble-sawdust, glued into a + paste with the insects' saliva. Whence are these materials obtained? Does + the Osmia go outside, to gather on the ground the rubbish which she flung + out when boring the cylinder? On the contrary, she is frugal of her time + and has better things to do than to pick up the scattered particles from + the soil. The channel, as I said, is at first uniform in size, almost + cylindrical; its sides still retain a thin coating of pith, forming the + reserves which the Osmia, as a provident builder, has economized wherewith + to construct the partitions. So she scrapes away with her mandibles, + keeping within a certain radius, a radius that corresponds with the + dimensions of the cell which she is going to build next; moreover, she + conducts her work in such a way as to hollow out more in the middle and + leave the two ends contracted. In this manner, the cylindrical channel of + the start is succeeded, in the worked portion, by an ovoid cavity + flattened at both ends, a space resembling a little barrel. This space + will form the second cell. + </p> + <p> + As for the rubbish, it is utilized on the spot for the lid or cover that + serves as a ceiling for one cell and a floor for the next. Our own + master-builders could not contrive more successfully to make the best use + of their labourers' time. On the floor thus obtained, a second ration of + honey is placed; and an egg is laid on the surface of the paste. Lastly, + at the upper end of the little barrel, a partition is built with the + scrapings obtained in the course of the final work on the third cell, + which itself is shaped like a flattened ovoid. And so the work goes on, + cell upon cell, each supplying the materials for the partition separating + it from the one below. On reaching the end of the cylinder, the Osmia + closes up the case with a thick layer of the same mortar. Then that + bramble-stump is done with; the Bee will not return to it. If her ovaries + are not yet exhausted, other dry stems will be exploited in the same + fashion. + </p> + <p> + The number of cells varies greatly, according to the qualities of the + stalk. If the bramble-stump be long, regular and smooth, we may count as + many as fifteen: that, at least, is the highest figure which my + observations have supplied. To obtain a good idea of the internal + distribution, we must split the stalk lengthwise, in the winter, when the + provisions have long been consumed and when the larvae are wrapped in + their cocoons. We then see that, at regular intervals, the case becomes + slightly narrower; and in each of the necks thus formed a circular disk is + fixed, a partition one or two millimetres thick. (.039 to.079 inch.—Translator's + Note.) The rooms separated by these partitions form so many little barrels + or kegs, each compactly filled with a reddish, transparent cocoon, through + which the larva shows, bent into a fish-hook. The whole suggests a string + of rough, oval amber beads, touching at their amputated ends. + </p> + <p> + In this string of cocoons, which is the oldest, which the youngest? The + oldest is obviously the bottom one, the one whose cell was the first + built; the youngest is the one at the top of the row, the one in the cell + last built. The oldest of the larvae starts the pile, down at the bottom + of the gallery; the latest arrival ends it at the top; and those in + between follow upon one another, according to age, from base to apex. + </p> + <p> + Let us next observe that there is no room in the shaft for two Osmiae at a + time on the same level, for each cocoon fills up the storey, the keg that + belongs to it, without leaving any vacant space; let us also remark that, + when they attain the stage of perfection, the Osmiae must all emerge from + the shaft by the only orifice which the bramble-stem boasts, the orifice + at the top. There is here but one obstacle, easy to overcome: a plug of + glued pith, of which the insect's mandibles make short work. Down below, + the stalk offers no ready outlet; besides, it is prolonged underground + indefinitely by the roots. Everywhere else is the ligneous fence, + generally too hard and thick to break through. It is inevitable therefore + that all the Osmiae, when the time comes to quit their dwelling, should go + out by the top; and, as the narrowness of the shaft bars the passage of + the preceding insect as long as the next insect, the one above it, remains + in position, the removal must begin at the top, extend from cell to cell + and end at the bottom. Consequently, the order of exit is the converse to + the order of birth: the younger Osmiae leave the nest first, their elders + leave it last. + </p> + <p> + The oldest, that is to say, the bottom one, was the first to finish her + supply of honey and to spin her cocoon. Taking precedence of all her + sisters in the whole series of her actions, she was the first to burst her + silken bag and to destroy the ceiling that closes her room: at least, that + is what the logic of the situation takes for granted. In her anxiety to + get out, how will she set about her release? The way is blocked by the + nearest cocoons, as yet intact. To clear herself a passage through the + string of those cocoons would mean to exterminate the remainder of the + brood; the deliverance of one would mean the destruction of all the rest. + Insects are notoriously obstinate in their actions and unscrupulous in + their methods. If the Bee at the bottom of the shaft wants to leave her + lodging, will she spare those who bar her road? + </p> + <p> + The difficulty is great, obviously; it seems insuperable. Thereupon we + become suspicious: we begin to wonder if the emergence from the cocoon, + that is to say, the hatching, really takes place in the order of + primogeniture. Might it not be—by a very singular exception, it is + true, but one which is necessary in such circumstances—that the + youngest of the Osmiae bursts her cocoon first and the oldest last; in + short, that the hatching proceeds from one chamber to the next in the + inverse direction to that which the age of the occupants would lead us to + presume? In that case, the whole difficulty would be removed: each Osmia, + as she rent her silken prison, would find a clear road in front of her, + the Osmiae nearer the outlet having gone out before her. But is this + really how things happen? Our theories very often do not agree with the + insect's practice; even where our reasoning seems most logical, we should + be more prudent to see what happens before venturing on any positive + statements. Leon Dufour was not so prudent when he, the first in the + field, took this little problem in hand. He describes to us the habits of + an Odynerus (Odynerus rubicola, DUF.) who piles up clay cells in the shaft + of a dry bramble-stalk; and, full of enthusiasm for his industrious Wasp, + he goes on to say: + </p> + <p> + 'Picture a string of eight cement shells, placed end to end and closely + wedged inside a wooden sheath. The lowest was undeniably made first and + consequently contains the first-laid egg, which, according to rules, + should give birth to the first winged insect. How do you imagine that the + larva in that first shell was bidden to waive its right of primogeniture + and only to complete its metamorphosis after all its juniors? What are the + conditions brought into play to produce a result apparently so contrary to + the laws of nature? Humble yourself in the presence of the reality and + confess your ignorance, rather than attempt to hide your embarrassment + under vain explanations! + </p> + <p> + 'If the first egg laid by the busy mother were destined to be the + first-born of the Odyneri, that one, in order to see the light immediately + after achieving wings, would have had the option either of breaking + through the double walls of his prison or of perforating, from bottom to + top, the seven shells ahead of him, in order to emerge through the + truncate end of the bramble-stem. Now nature, while refusing any way of + escape laterally, was also bound to veto any direct invasion, the brutal + gimlet-work which would inevitably have sacrificed seven members of one + family for the safety of an only son. Nature is as ingenious in design as + she is fertile in resource, and she must have foreseen and forestalled + every difficulty. She decided that the last-built cradle should yield the + first-born child; that this one should clear the road for his next oldest + brother, the second for the third and so on. And this is the order in + which the birth of our Odyneri of the Brambles actually takes place.' + </p> + <p> + Yes, my revered master, I will admit without hesitation that the + bramble-dwellers leave their sheath in the converse order to that of their + ages: the youngest first, the oldest last; if not invariably, at least + very often. But does the hatching, by which I mean the emergence from the + cocoon, take place in the same order? Does the evolution of the elder wait + upon that of the younger, so that each may give those who would bar his + passage time to effect their deliverance and to leave the road clear? I + very much fear that logic has carried your deductions beyond the bounds of + reality. Rationally speaking, my dear sir, nothing could be more accurate + than your inferences; and yet we must forgo the theory of the strange + inversion which you suggest. None of the Bramble-bees with whom I have + experimented behaves after that fashion. I know nothing personal about + Odynerus rubicola, who appears to be a stranger in my district; but, as + the method of leaving must be almost the same when the habitation is + exactly similar, it is enough, I think, to experiment with some of the + bramble-dwellers in order to learn the history of the rest. + </p> + <p> + My studies will, by preference, bear upon the Three-pronged Osmia, who + lends herself more readily to laboratory experiments, both because she is + stronger and because the same stalk will contain a goodly number of her + cells. The first fact to be ascertained is the order of hatching. I take a + glass tube, closed at one end, open at the other and of a diameter similar + to that of the Osmia's tunnel. In this I place, one above the other, + exactly in their natural order, the ten cocoons, or thereabouts, which I + extract from a stump of bramble. The operation is performed in winter. The + larvae, at that time, have long been enveloped in their silken case. To + separate the cocoons from one another, I employ artificial partitions + consisting of little round disks of sorghum, or Indian millet, about half + a centimetre thick. (About one-fifth of an inch.—Translator's Note.) + This is a white pith, divested of its fibrous wrapper and easy for the + Osmia's mandibles to attack. My diaphragms are much thicker than the + natural partitions; this is an advantage, as we shall see. In any case, I + could not well use thinner ones, for these disks must be able to withstand + the pressure of the rammer which places them in position in the tube. On + the other hand, the experiment showed me that the Osmia makes short work + of the material when it is a case of drilling a hole through it. + </p> + <p> + To keep out the light, which would disturb my insects destined to spend + their larval life in complete darkness, I cover the tube with a thick + paper sheath, easy to remove and replace when the time comes for + observation. Lastly, the tubes thus prepared and containing either Osmiae + or other bramble-dwellers are hung vertically, with the opening at the + top, in a snug corner of my study. Each of these appliances fulfils the + natural conditions pretty satisfactorily: the cocoons from the same + bramble-stick are stacked in the same order which they occupied in the + native shaft, the oldest at the bottom of the tube and the youngest close + to the orifice; they are isolated by means of partitions; they are placed + vertically, head upwards; moreover, my device has the advantage of + substituting for the opaque wall of the bramble a transparent wall which + will enable me to follow the hatching day by day, at any moment which I + think opportune. + </p> + <p> + The male Osmia splits his cocoon at the end of June and the female at the + beginning of July. When this time comes, we must redouble our watch and + inspect the tubes several times a day if we would obtain exact statistics + of the births. Well, during the six years that I have studied this + question, I have seen and seen again, ad nauseam; and I am in a position + to declare that there is no order governing the sequence of hatchings, + absolutely none. The first cocoon to burst may be the one at the bottom of + the tube, the one at the top, the one in the middle or in any other part, + indifferently. The second to be split may adjoin the first or it may be + removed from it by a number of spaces, either above or below. Sometimes + several hatchings occur on the same day, within the same hour, some + farther back in the row of cells, some farther forward; and this without + any apparent reason for the simultaneity. In short, the hatchings follow + upon one another, I will not say haphazard—for each of them has its + appointed place in time, determined by impenetrable causes—but at + any rate contrary to our calculations, based on this or the other + consideration. + </p> + <p> + Had we not been deceived by our too shallow logic, we might have foreseen + this result. The eggs are laid in their respective cells at intervals of a + few days, of a few hours. How can this slight difference in age affect the + total evolution, which lasts a year? Mathematical accuracy has nothing to + do with the case. Each germ, each grub has its individual energy, + determined we know not how and varying in each germ or grub. This excess + of vitality belongs to the egg before it leaves the ovary. Might it not, + at the moment of hatching, be the cause why this or that larva takes + precedence of its elders or its juniors, chronology being altogether a + secondary consideration? When the hen sits upon her eggs, is the oldest + always the first to hatch? In the same way, the oldest larva, lodged in + the bottom storey, need not necessarily reach the perfect state first. + </p> + <p> + A second argument, had we reflected more deeply on the matter, would have + shaken our faith in any strict mathematical sequence. The same brood + forming the string of cocoons in a bramble-stem contains both males and + females; and the two sexes are divided in the series indiscriminately. Now + it is the rule among the Bees for the males to issue from the cocoon a + little earlier than the females. In the case of the Three-pronged Osmia, + the male has about a week's start. Consequently, in a populous gallery, + there is always a certain number of males, who are hatched seven or eight + days before the females and who are distributed here and there over the + series. This would be enough to make any regular hatching-sequence + impossible in either direction. + </p> + <p> + These surmises accord with the facts: the chronological sequence of the + cells tells us nothing about the chronological sequence of the hatchings, + which take place without any definite order. There is, therefore, no + surrender of rights of primogeniture, as Leon Dufour thought: each insect, + regardless of the others, bursts its cocoon when its time comes; and this + time is determined by causes which escape our notice and which, no doubt, + depend upon the potentialities of the egg itself. It is the case with the + other bramble-dwellers which I have subjected to the same test (Osmia + detrita, Anthidium scapulare, Solenius vagus, etc.); and it must also be + the case with Odynerus rubicola: so the most striking analogies inform us. + Therefore the singular exception which made such an impression on Dufour's + mind is a sheer logical illusion. + </p> + <p> + An error removed is tantamount to a truth gained; and yet, if it were to + end here, the result of my experiment would possess but slight value. + After destruction, let us turn to construction; and perhaps we shall find + the wherewithal to compensate us for an illusion lost. Let us begin by + watching the exit. + </p> + <p> + The first Osmia to leave her cocoon, no matter what place she occupies in + the series, forthwith attacks the ceiling separating her from the floor + above. She cuts a fairly clean hole in it, shaped like a truncate cone, + having its larger base on the side where the Bee is and its smaller base + opposite. This conformation of the exit-door is a characteristic of the + work. When the insect tries to attack the diaphragm, it first digs more or + less at random; then, as the boring progresses, the action is concentrated + upon an area which narrows until it presents no more than just the + necessary passage. Nor is the cone-shaped aperture special to the Osmia: I + have seen it made by the other bramble-dwellers through my thick disks of + sorghum-pith. Under natural conditions, the partitions, which, for that + matter, are very thin, are destroyed absolutely, for the contraction of + the cell at the top leaves barely the width which the insect needs. The + truncate, cone-shaped breach has often been of great use to me. Its wide + base made it possible for me, without being present at the work, to judge + which of the two neighbouring Osmiae had pierced the partition; it told me + the direction of a nocturnal migration which I had been unable to witness. + </p> + <p> + The first-hatched Osmia, wherever she may be, has made a hole in her + ceiling. She is now in the presence of the next cocoon, with her head at + the opening of the hole. In front of her sister's cradle, she usually + stops, consumed with shyness; she draws back into her cell, flounders + among the shreds of the cocoon and the wreckage of the ruined ceiling; she + waits a day, two days, three days, more if necessary. Should impatience + gain the upper hand, she tries to slip between the wall of the tunnel and + the cocoon that blocks the way. She even undertakes the laborious work of + gnawing at the wall, so as to widen the interval, if possible. We find + these attempts, in the shaft of a bramble, at places where the pith is + removed down to the very wood, where the wood itself is gnawed to some + depth. I need hardly say that, although these lateral inroads are + perceptible after the event, they escape the eye at the moment when they + are being made. + </p> + <p> + If we would witness them, we must slightly modify the glass apparatus. I + line the inside of the tube with a thick piece of whity-brown + packing-paper, but only over one half of the circumference; the other half + is left bare, so that I may watch the Osmia's attempts. Well, the captive + insect fiercely attacks this lining, which to its eyes represents the + pithy layer of its usual abode; it tears it away by tiny particles and + strives to cut itself a road between the cocoon and the glass wall. The + males, who are a little smaller, have a better chance of success than the + females. Flattening themselves, making themselves thin, slightly spoiling + the shape of the cocoon, which, however, thanks to its elasticity, soon + recovers its first condition, they slip through the narrow passage and + reach the next cell. The females, when in a hurry to get out, do as much, + if they find the tube at all amenable to the process. But no sooner is the + first partition passed than a second presents itself. This is pierced in + its turn. In the same way will the third be pierced and others after that, + if the insect can manage them, as long as its strength holds out. Too weak + for these repeated borings, the males do not go far through my thick + plugs. If they contrive to cut through the first, it is as much as they + can do; and, even so, they are far from always succeeding. But, in the + conditions presented by the native stalk, they have only feeble tissues to + overcome; and then, slipping, as I have said, between the cocoon and the + wall, which is slightly worn owing to the circumstances described, they + are able to pass through the remaining occupied chambers and to reach the + outside first, whatever their original place in the stack of cells. It is + just possible that their early eclosion forces this method of exit upon + them, a method which, though often attempted, does not always succeed. The + females, furnished with stronger tools, make greater progress in my tubes. + I see some who pierce three or four partitions, one after the other, and + are so many stages ahead before those whom they have left behind are even + hatched. While they are engaged in this long and toilsome operation, + others, nearer to the orifice, have cleared a passage whereof those from a + distance will avail themselves. In this way, it may happen that, when the + width of the tube permits, an Osmia in a back row will nevertheless be one + of the first to emerge. + </p> + <p> + In the bramble-stem, which is of exactly the same diameter as the cocoon, + this escape by the side of the column appears hardly practicable, except + to a few males; and even these have to find a wall which has so much pith + that by removing it they can effect a passage. Let us then imagine a tube + so narrow as to prevent any exit save in the natural sequence of the + cells. What will happen? A very simple thing. The newly-hatched Osmia, + after perforating his partition, finds himself faced with an unbroken + cocoon that obstructs the road. He makes a few attempts upon the sides + and, realizing his impotence, retires into his cell, where he waits for + days and days, until his neighbour bursts her cocoon in her turn. His + patience is inexhaustible. However, it is not put to an over long test, + for within a week, more or less, the whole string of females is hatched. + </p> + <p> + When two neighbouring Osmiae are released at the same time, mutual visits + are paid through the aperture between the two rooms: the one above goes + down to the floor below; the one below goes up to the floor above; + sometimes both of them are in the same cell together. Might not this + intercourse tend to cheer them and encourage them to patience? Meanwhile, + slowly, doors are opening here and there through the separating walls; the + road is cleared by sections; and a moment arrives when the leader of the + file walks out. The others follow, if ready; but there are always laggards + who keep the rear-ranks waiting until they are gone. + </p> + <p> + To sum up, first, the hatching of the larvae takes place without any + order; secondly, the exodus proceeds regularly from summit to base, but + only in consequence of the insect's inability to move forward so long as + the upper cells are not vacated. We have here not an exceptional + evolution, in the inverse ratio to age, but the simple impossibility of + emerging otherwise. Should a chance occur of going out before its turn, + the insect does not fail to seize it, as we can see by the lateral + movements which send the impatient ones a few ranks ahead and even release + the more favoured altogether. The only remarkable thing that I perceive is + the scrupulous respect shown to the as yet unopened neighbouring cocoon. + However eager to come out, the Osmia is most careful not to touch it with + his mandibles: it is taboo. He will demolish the partition, he will gnaw + the side-wall fiercely, even though there be nothing left but wood, he + will reduce everything around him to dust; but touch a cocoon that + obstructs his way? Never! He will not make himself an outlet by breaking + up his sisters' cradles. + </p> + <p> + It may happen that the Osmia's patience is in vain and that the barricade + that blocks the way never disappears at all. Sometimes, the egg in a cell + does not mature; and the unconsumed provisions dry up and become a + compact, sticky, mildewed plug, through which the occupants of the floors + below could never clear themselves a passage. Sometimes, again, a grub + dies in its cocoon; and the cradle of the deceased, now turned into a + coffin, forms an everlasting obstacle. How shall the insect cope with such + grave circumstances? + </p> + <p> + Among the many bramble-stumps which I have collected, some few have + presented a remarkable peculiarity. In addition to the orifice at the top, + they had at the side one and sometimes two round apertures that looked as + though they had been punched out with an instrument. On opening these + stalks, which were old, deserted nests, I discovered the cause of these + very exceptional windows. Above each of them was a cell full of mouldy + honey. The egg had perished and the provisions remained untouched: hence + the impossibility of getting out by the ordinary road. Walled in by the + unsurmountable obstacle, the Osmia on the floor below had contrived an + outlet through the side of the shaft; and those in the lower storeys had + benefited by this ingenious innovation. The usual door being inaccessible, + a side-window had been opened by means of the insect's jaws. The cocoons, + torn, but still in position in the lower rooms, left no doubt as to this + eccentric mode of exit. The same fact, moreover, was repeated, in several + bramble-stumps, in the case of Osmia tridentata; it was likewise repeated + in the case of Anthidium scapulare. The observation was worth confirming + by experiment. + </p> + <p> + I select a bramble-stem with the thinnest rind possible, so as to + facilitate the Osmiae's work. I split it in half, thus obtaining a + smooth-sided trough which will enable me to judge better of future exits. + The cocoons are next laid out in one of the troughs. I separate them with + disks of sorghum, covering both surfaces of the disk with a generous layer + of sealing-wax, a material which the Osmia's mandibles are not able to + attack. The two troughs are then placed together and fastened. A little + putty does away with the joint and prevents the least ray of light from + penetrating. Lastly, the apparatus is hung up perpendicularly, with the + cocoons' heads up. We have now only to wait. None of the Osmiae can get + out in the usual manner, because each of them is confined between two + partitions coated with sealing-wax. There is but one resource left to them + if they would emerge into the light of day, that is, for each of them to + open a side-window, provided always that they possess the instinct and the + power to do so. + </p> + <p> + In July, the result is as follows: of twenty Osmiae thus immured, six + succeed in boring a round hole through the wall and making their way out; + the others perish in their cells, without managing to release themselves. + But, when I open the cylinder, when I separate the two wooden troughs, I + realize that all have attempted to escape through the side, for the wall + of each cell bears traces of gnawing concentrated upon one spot. All, + therefore, have acted in the same way as their more fortunate sisters; + they did not succeed, because their strength failed them. Lastly, in my + glass tubes, part-lined with a thick piece of packing-paper, I often see + attempts at making a window in the side of the cell: the paper is pierced + right through with a round hole. + </p> + <p> + This then is yet another result which I am glad to record in the history + of the bramble-dwellers. When the Osmia, the Anthidium and probably others + are unable to emerge through the customary outlet, they take an heroic + decision and perforate the side of the shaft. It is the last resource, + resolved upon after other methods have been tried in vain. The brave, the + strong succeed; the weak perish in the attempt. + </p> + <p> + Supposing that all the Osmiae possessed the necessary strength of jaw as + well as the instinct for this sideward boring, it is clear that egress + from each cell through a special window would be much more advantageous + than egress through the common door. The Bee could attend to his release + as soon as he was hatched, instead of postponing it until after the + emancipation of those who come before him; he would thus escape long + waits, which too often prove fatal. In point of fact, it is no uncommon + thing to find bramble-stalks in which several Osmiae have died in their + cells, because the upper storeys were not vacated in time. Yes, there + would be a precious advantage in that lateral opening, which would not + leave each occupant at the mercy of his environment: many die that would + not die. All the Osmiae, when compelled by circumstances, resort to this + supreme method; all have the instinct for lateral boring; but very few are + able to carry the work through. Only the favourites of fate succeed, those + more generously endowed with strength and perseverance. + </p> + <p> + If the famous law of natural selection, which is said to govern and + transform the world, had any sure foundation; if really the fittest + removed the less fit from the scene; if the future were to the strongest, + to the most industrious, surely the race of Osmiae, which has been + perforating bramble-stumps for ages, should by this time have allowed its + weaker members, who go on obstinately using the common outlet, to die out + and should have replaced them, down to the very last one, by the stalwart + drillers of side-openings. There is an opportunity here for immense + progress; the insect is on the verge of it and is unable to cross the + narrow intervening line. Selection has had ample time to make its choice; + and yet, though there be a few successes, the failures exceed them in very + large measure. The race of the strong has not abolished the race of the + weak: it remains inferior in numbers, as doubtless it has been since all + time. The law of natural selection impresses me with the vastness of its + scope; but, whenever I try to apply it to actual facts, it leaves me + whirling in space, with nothing to help me to interpret realities. It is + magnificent in theory, but it is a mere gas-bubble in the face of existing + conditions. It is majestic, but sterile. Then where is the answer to the + riddle of the world? Who knows? Who will ever know? + </p> + <p> + Let us waste no more time in this darkness, which idle theorizing will not + dispel; let us return to facts, humble facts, the only ground that does + not give way under our feet. The Osmia respects her neighbour's cocoon; + and her scruples are so great that, after vainly trying to slip between + that cocoon and the wall, or else to open a lateral outlet, she lets + herself die in her cell rather than effect an egress by forcing her way + through the occupied cells. When the cocoon that blocks the way contains a + dead instead of a live grub, will the result be the same? + </p> + <p> + In my glass tubes, I let Osmia-cocoons containing a live grub alternate + with Osmia-cocoons in which the grub has been asphyxiated by the fumes of + sulphocarbonic acid. As usual, the storeys are separated by disks of + sorghum. The anchorites, when hatched, do not hesitate long. Once the + partition is pierced, they attack the dead cocoons, go right through them, + reducing the dead grub, now dry and shrivelled, to dust, and at last + emerge, after wrecking everything in their path. The dead cocoons, + therefore, are not spared; they are treated as would be any other obstacle + capable of attack by the mandibles. The Osmia looks upon them as a mere + barricade to be ruthlessly overturned. How is she apprised that the + cocoon, which has undergone no outward change, contains a dead and not a + live grub? It is certainly not by sight. Can it be by sense of smell? I am + always a little suspicious of that sense of smell of which we do not know + the seat and which we introduce on the slightest provocation as a + convenient explanation of that which may transcend our explanatory powers. + </p> + <p> + My next test is made with a string of live cocoons. Of course, I cannot + take all these from the same species, for then the experiment would not + differ from the one which we have already witnessed; I take them from two + different species which leave their bramble-stem at separate periods. + Moreover, these cocoons must have nearly the same diameter to allow of + their being stacked in a tube without leaving an empty space between them + and the wall. The two species adopted are Solenius vagus, which quits the + bramble at the end of June, and Osmia detrita, which comes a little + earlier, in the first fortnight of the same month. I therefore alternate + Osmia-cocoons and Solenius-cocoons, with the latter at the top of the + series, either in glass tubes or between two bramble-troughs joined into a + cylinder. + </p> + <p> + The result of this promiscuity is striking. The Osmiae, which mature + earlier, emerge; and the Solenius-cocoons, as well as their inhabitants, + which by this time have reached the perfect stage, are reduced to shreds, + to dust, wherein it is impossible for me to recognize a vestige, save + perhaps here and there a head, of the exterminated unfortunates. The + Osmia, therefore, has not respected the live cocoons of a foreign species: + she has passed out over the bodies of the intervening Solenii. Did I say + passed over their bodies? She has passed through them, crunched the + laggards between her jaws, treated them as cavalierly as she treats my + disks. And yet those barricades were alive. No matter: when her hour came, + the Osmia went ahead, destroying everything upon her road. Here, at any + rate, is a law on which we can rely: the supreme indifference of the + animal to all that does not form part of itself and its race. + </p> + <p> + And what of the sense of smell, distinguishing the dead from the living? + Here, all are alive; and the Bee pierces her way as through a row of + corpses. If I am told that the smell of the Solenii may differ from that + of the Osmiae, I shall reply that such extreme subtlety in the insect's + olfactory apparatus seems to me a rather far-fetched supposition. Then + what is my explanation of the two facts? The explanation? I have none to + give! I am quite content to know that I do not know, which at least spares + me many vain lucubrations. And so I do not know how the Osmia, in the + dense darkness of her tunnel, distinguishes between a live cocoon and a + dead cocoon of the same species; and I know just as little how she + succeeds in recognizing a strange cocoon. Ah, how clearly this confession + of ignorance proves that I am behind the times! I am deliberately missing + a glorious opportunity of stringing big words together and arriving at + nothing. + </p> + <p> + The bramble-stump is perpendicular, or nearly so; its opening is at the + top. This is the rule under natural conditions. My artifices are able to + alter that state of things; I can place the tube vertically or + horizontally; I can turn its one orifice either up or down; lastly, I can + leave the channel open at both ends, which will give two outlets. What + will happen under these several conditions? That is what we shall examine + with the Three-pronged Osmia. + </p> + <p> + The tube is hung perpendicularly, but closed at the top and open at the + bottom; in fact, it represents a bramble-stump turned upside down. To vary + and complicate the experiment, the strings of cocoons are arranged + differently in different tubes. In some of them, the heads of the cocoons + are turned downwards, towards the opening; in others, they are turned + upwards, towards the closed end; in others again, the cocoons alternate in + direction, that is to say, they are placed head to head and rear to rear, + turn and turn about. I need not say that the separating floors are of + sorghum. + </p> + <p> + The result is identical in all these tubes. If the Osmiae have their heads + pointing upwards, they attack the partition above them, as happens under + normal conditions; if their heads point downwards, they turn round in + their cells and set to work as usual. In short, the general outward trend + is towards the top, in whatever position the cocoon be placed. + </p> + <p> + We here see manifestly at work the influence of gravity, which warns the + insect of its reversed position and makes it turn round, even as it would + warn us if we ourselves happened to be hanging head downwards. In natural + conditions, the insect has but to follow the counsels of gravity, which + tells it to dig upwards, and it will infallibly reach the exit-door + situated at the upper end. But, in my apparatus, these same counsels + betray it: it goes towards the top, where there is no outlet. Thus misled + by my artifices, the Osmiae perish, heaped up on the higher floors and + buried in the ruins. + </p> + <p> + It nevertheless happens that attempts are made to clear a road downwards. + But it is rare for the work to lead to anything in this direction, + especially in the case of the middle or upper cells. The insect is little + inclined for this progress, the opposite to that to which it is + accustomed; besides, a serious difficulty arises in the course of this + reversed boring. As the Bee flings the excavated materials behind her, + these fall back of their own weight under her mandibles; the clearance has + to be begun anew. Exhausted by her Sisyphean task, distrustful of this new + and unfamiliar method, the Osmia resigns herself and expires in her cell. + I am bound to add, however, that the Osmiae in the lower storeys, those + nearest the exit—sometimes one, sometimes two or three—do + succeed in escaping. In that case, they unhesitatingly attack the + partitions below them, while their companions, who form the great + majority, persist and perish in the upper cells. + </p> + <p> + It was easy to repeat the experiment without changing anything in the + natural conditions, except the direction of the cocoons: all that I had to + do was to hang up some bramble-stumps as I found them, vertically, but + with the opening downwards. Out of two stalks thus arranged and peopled + with Osmiae, not one of the insects succeeded in emerging. All the Bees + died in the shaft, some turned upwards, others downwards. On the other + hand, three stems occupied by Anthidia discharged their population safe + and sound. The outgoing was effected at the bottom, from first to last, + without the least impediment. Must we take it that the two sorts of Bees + are not equally sensitive to the influences of gravity? Can the Anthidium, + built to pass through the difficult obstacle of her cotton wallets, be + better-adapted than the Osmia to make her way through the wreckage that + keeps falling under the worker's feet; or, rather, may not this very + cotton-waste put a stop to these cataracts of rubbish which must naturally + drive the insect back? This is all quite possible; but I can say nothing + for certain. + </p> + <p> + Let us now experiment with vertical tubes open at both ends. The + arrangements, save for the upper orifice, are the same as before. The + cocoons, in some of the tubes, have their heads turned down; others, up; + in others again, their positions alternate. The result is similar to what + we have seen above. A few Osmiae, those nearest the bottom orifice, take + the lower road, whatever the direction first occupied by the cocoon; the + others, composing by far the larger number, take the higher road, even + when the cocoon is placed upside down. As both doors are free, the + outgoing is effected at either end with success. + </p> + <p> + What are we to conclude from all these experiments? First, that gravity + guides the insect towards the top, where the natural door is, and makes it + turn in its cell when the cocoon has been reversed. Secondly, I seem to + suspect an atmospheric influence and, in any case, some second cause that + sends the insect to the outlet. Let us admit that this cause is the + proximity of the outer air acting upon the anchorite through the + partitions. + </p> + <p> + The animal then is subject, on the one hand, to the promptings of gravity, + and this to an equal degree for all, whatever the storey inhabited. + Gravity is the common guide of the whole series from base to top. But + those in the lower boxes have a second guide, when the bottom end is open. + This is the stimulus of the adjacent air, a more powerful stimulus than + that of gravity. The access of the air from without is very slight, + because of the partitions; while it can be felt in the nethermost cells, + it must decrease rapidly as the storeys ascend. Wherefore the bottom + insects, very few in number, obeying the preponderant influence, that of + the atmosphere, make for the lower outlet and reverse, if necessary, their + original position; those above, on the contrary, who form the great + majority, being guided only by gravity when the upper end is closed, make + for that upper end. It goes without saying that, if the upper end be open + at the same time as the other, the occupants of the top storeys will have + a double incentive to take the ascending path, though this will not + prevent the dwellers on the lower floors from obeying, by preference, the + call of the adjacent air and adopting the downward road. + </p> + <p> + I have one means left whereby to judge of the value of my explanation, + namely, to experiment with tubes open at both ends and lying horizontally. + The horizontal position has a twofold advantage. In the first place, it + removes the insect from the influence of gravity, inasmuch as it leaves it + indifferent to the direction to be taken, the right or the left. In the + second place, it does away with the descent of the rubbish which, falling + under the worker's feet when the boring is done from below, sooner or + later discourages her and makes her abandon her enterprise. + </p> + <p> + There are a few precautions to be observed for the successful conduct of + the experiment; I recommend them to any one who might care to make the + attempt. It is even advisable to remember them in the case of the tests + which I have already described. The males, those puny creatures, not built + for work, are sorry labourers when confronted with my stout disks. Most of + them perish miserably in their glass cells, without succeeding in piercing + their partitions right through. Moreover, instinct has been less generous + to them than to the females. Their corpses, interspersed here and there in + the series of the cells, are disturbing causes, which it is wise to + eliminate. I therefore choose the larger, more powerful-looking cocoons. + These, except for an occasional unavoidable error, belong to females. I + pack them in tubes, sometimes varying their position in every way, + sometimes giving them all a like arrangement. It does not matter whether + the whole series comes from one and the same bramble-stump or from + several: we are free to choose where we please; the result will not be + altered. + </p> + <p> + The first time that I prepared one of these horizontal tubes open at both + ends, I was greatly struck by what happened. The series consisted of ten + cocoons. It was divided into two equal batches. The five on the left went + out on the left, the five on the right went out on the right, reversing, + when necessary, their original direction in the cell. It was very + remarkable from the point of view of symmetry; moreover, it was a very + unlikely arrangement among the total number of possible arrangements, as + mathematics will show us. + </p> + <p> + Let us take n to represent the number of Osmiae. Each of them, once + gravity ceases to interfere and leaves the insect indifferent to either + end of the tube, is capable of two positions, according as she chooses the + exit on the right or on the left. With each of the two positions of this + first Osmia can be combined each of the two positions of the second, + giving us, in all, 2 x 2 = (2 squared) arrangements. Each of these (2 + squared) arrangements can be combined, in its turn, with each of the two + positions of the third Osmia. We thus obtain 2 x 2 x 2 = (2 cubed) + arrangements with three Osmiae; and so on, each additional insect + multiplying the previous result by the factor 2. With n Osmiae, therefore, + the total number of arrangements is (2 to the power n.) + </p> + <p> + But note that these arrangements are symmetrical, two by two: a given + arrangement towards the right corresponds with a similar arrangement + towards the left; and this symmetry implies equality, for, in the problem + in hand, it is a matter of indifference whether a fixed arrangement + correspond with the right or left of the tube. The previous number, + therefore, must be divided by 2. Thus, n Osmiae, according as each of them + turns her head to the right or left in my horizontal tube, are able to + adopt (2 to the power n - 1) arrangements. If n = 10, as in my first + experiment, the number of arrangements becomes (2 to the power 9) = 512. + </p> + <p> + Consequently, out of 512 ways which my ten insects can adopt for their + outgoing position, there resulted one of those in which the symmetry was + most striking. And observe that this was not an effect obtained by + repeated attempts, by haphazard experiments. Each Osmia in the left half + had bored to the left, without touching the partition on the right; each + Osmia in the right half had bored to the right, without touching the + partition on the left. The shape of the orifices and the surface condition + of the partition showed this, if proof were necessary. There had been a + spontaneous decision, one half in favour of the left, one half in favour + of the right. + </p> + <p> + The arrangement presents another merit, one superior to that of symmetry: + it has the merit of corresponding with the minimum expenditure of force. + To admit of the exit of the whole series, if the string consists of n + cells, there are originally n partitions to be perforated. There might + even be one more, owing to a complication which I disregard. There are, I + say, at least n partitions to be perforated. Whether each Osmia pierces + her own, or whether the same Osmia pierces several, thus relieving her + neighbours, does not matter to us: the sum-total of the force expended by + the string of Bees will be in proportion to the number of those + partitions, in whatever manner the exit be effected. + </p> + <p> + But there is another task which we must take seriously into consideration, + because it is often more troublesome than the boring of the partition: I + mean the work of clearing a road through the wreckage. Let us suppose the + partitions pierced and the several chambers blocked by the resulting + rubbish and by that rubbish only, since the horizontal position precludes + any mixing of the contents of different chambers. To open a passage for + itself through these rubbish-heaps, each insect will have the smallest + effort to make if it passes through the smallest possible number of cells, + in short, if it makes for the opening nearest to it. These smallest + individual efforts amount, in the aggregate, to the smallest total effort. + Therefore, by proceeding as they did in my experiment, the Osmiae effect + their exit with the least expenditure of energy. It is curious to see an + insect apply the 'principle of least action,' so often postulated in + mechanics. + </p> + <p> + An arrangement which satisfies this principle, which conforms to the law + of symmetry and which possesses but one chance in 512, is certainly no + fortuitous result. It is determined by a cause; and, as this cause acts + invariably, the same arrangement must be reproduced if I renew the + experiment. I renewed it, therefore, in the years that followed, with as + many appliances as I could find bramble-stumps; and, at each new test, I + saw once more what I had seen with such interest on the first occasion. If + the number be even—and my column at that time consisted usually of + ten—one half goes out on the right, the other on the left. If the + number be odd—eleven, for instance—the Osmia in the middle + goes out indiscriminately by the right or left exit. As the number of + cells to be traversed is the same on both sides, her expenditure of energy + does not vary with the direction of the exit; and the principle of least + action is still observed. + </p> + <p> + It was important to discover if the Three-pronged Osmia shared her + capacity, in the first place, with the other bramble-dwellers and, in the + second, with Bees differently housed, but also destined laboriously to cut + a new road for themselves when the hour comes to quit the nest. Well, + apart from a few irregularities, due either to cocoons whose larva + perished in my tubes before developing, or to those inexperienced workers, + the males, the result was the same in the case of Anthidium scapulare. The + insects divided themselves into two equal batches, one going to the right, + the other to the left. Tripoxylon figulus left me undecided. This feeble + insect is not capable of perforating my partitions; it nibbles at them a + little; and I had to judge the direction from the marks of its mandibles. + These marks, which are not always very plain, do not yet allow me to + pronounce an opinion. Solenius vagus, who is a skilful borer, behaved + differently from the Osmia. In a column of ten, the whole exodus was made + in one direction. + </p> + <p> + On the other hand, I tested the Mason-bee of the Sheds, who, when emerging + under natural conditions, has only to pierce her cement ceiling and is not + confronted with a series of cells. Though a stranger to the environment + which I created for her, she gave me a most positive answer. Of a column + of ten laid in a horizontal tube open at both ends, five made their way to + the right and five to the left. Dioxys cincta, a parasite in the buildings + of both species of Mason-bees, the Chalicodoma of the Sheds and the + Chalicodoma of the Walls (Cf. "The Mason-bees" by J. Henri Fabre, + translated by Alexander Teixeira de Mattos: passim.—Translator's + Note.), provided me with no precise result. The Leaf-cutting Bee + (Megachile apicalis, SPIN. (Cf. Chapter 8 of the present volume.—Translator's + Note.)), who builds her leafy cups in the old cells of the Chalicodoma of + the Walls, acts like the Solenius and directs her whole column towards the + same outlet. + </p> + <p> + Incomplete as it is, this symmetry shows us how unwise it were to + generalize from the conclusions to which the Three-pronged Osmia leads us. + Whereas some Bees, such as the Anthidium and the Chalicodoma, share the + Osmia's talent for using the twofold exit, others, such as the Solenius + and the Leaf-cutter, behave like a flock of sheep and follow the first + that goes out. The entomological world is not all of a piece; its gifts + are very various: what one is capable of doing another cannot do; and + penetrating indeed would be the eyes that saw the causes of these + differences. Be this as it may, increased research will certainly show us + a larger number of species qualified to use the double outlet. For the + moment, we know three; and that is enough for our purpose. + </p> + <p> + I will add that, when the horizontal tube has one of its ends closed, the + whole string of Osmiae makes for the open end, turning round to do so, if + need be. + </p> + <p> + Now that the facts are set forth, let us, if possible, trace the cause. In + a horizontal tube, gravity no longer acts to determine the direction which + the insect will take. Is it to attack the partition on the right or that + on the left? How shall it decide? The more I look into the matter, the + more do my suspicions fall upon the atmospheric influence which is felt + through the two open ends. Of what does this influence consist? Is it an + effect of pressure, of hygrometry, of electrical conditions, of properties + that escape our coarser physical attunement? He were a bold man who should + undertake to decide. Are not we ourselves, when the weather is about to + alter, subject to subtle impressions, to sensations which we are unable to + explain? And yet this vague sensitiveness to atmospheric changes would not + be of much help to us in circumstances similar to those of my anchorites. + Imagine ourselves in the darkness and the silence of a prison-cell, + preceded and followed by other similar cells. We possess implements + wherewith to pierce the walls; but where are we to strike to reach the + final outlet and to reach it with the least delay? Atmospheric influence + would certainly never guide us. + </p> + <p> + And yet it guides the insect. Feeble though it be, through the + multiplicity of partitions, it is exercised on one side more than on the + other, because the obstacles are fewer; and the insect, sensible to the + difference between those two uncertainties, unhesitatingly attacks the + partition which is nearer to the open air. Thus is decided the division of + the column into two converse sections, which accomplish the total + liberation with the least aggregate of work. In short, the Osmia and her + rivals 'feel' the free space. This is yet one more sensory faculty which + evolution might well have left us, for our greater advantage. As it has + not done so, are we then really, as many contend, the highest expression + of the progress accomplished, throughout the ages, by the first atom of + glair expanded into a cell? + </p> + <p> + <a name="link2HCH0002" id="link2HCH0002"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 2. THE OSMIAE. + </h2> + <p> + February has its sunny days, heralding spring, to which rude winter will + reluctantly yield place. In snug corners, among the rocks, the great + spurge of our district, the characias of the Greeks, the jusclo of the + Provencals, begins to lift its drooping inflorescence and discreetly opens + a few sombre flowers. Here the first Midges of the year will come to slake + their thirst. By the time that the tip of the stalks reaches the + perpendicular, the worst of the cold weather will be over. + </p> + <p> + Another eager one, the almond-tree, risking the loss of its fruit, hastens + to echo these preludes to the festival of the sun, preludes which are too + often treacherous. A few days of soft skies and it becomes a glorious dome + of white flowers, each twinkling with a roseate eye. The country, which + still lacks green, seems dotted everywhere with white-satin pavilions. + 'Twould be a callous heart indeed that could resist the magic of this + awakening. + </p> + <p> + The insect nation is represented at these rites by a few of its more + zealous members. There is first of all the Honey-bee, the sworn enemy of + strikes, who profits by the least lull of winter to find out if some + rosemary is not beginning to open somewhere near the hive. The droning of + the busy swarm fills the flowery vault, while a snow of petals falls + softly to the foot of the tree. + </p> + <p> + Together with the population of harvesters there mingles another, less + numerous, of mere drinkers, whose nesting-time has not yet begun. This is + the colony of the Osmiae, with their copper-coloured skin and bright-red + fleece. Two species have come hurrying up to take part in the joys of the + almond-tree: first, the Horned Osmia, clad in black velvet on the head and + breast and in red velvet on the abdomen; and, a little later, the + Three-horned Osmia, whose livery must be red and red only. These are the + first delegates despatched by the pollen-gleaners to ascertain the state + of the season and attend the festival of the early blooms. 'Tis but a + moment since they burst their cocoon, the winter abode: they have left + their retreats in the crevices of the old walls; should the north wind + blow and set the almond-tree shivering, they will hasten to return to + them. Hail to you, O my dear Osmiae, who yearly, from the far end of the + harmas (The piece of waste ground in which the author studied his insects + in their natural state. Cf. "The Life of the Fly" by J. Henri Fabre, + translated by Alexander Teixeira de Mattos: chapter 1.—Translator's + Note.), opposite snow-capped Ventoux (A mountain in the Provencal Alps, + near Carpentras and Serignan, 6,271 feet.—Translator's Note.), bring + me the first tidings of the awakening of the insect world! I am one of + your friends; let us talk about you a little. + </p> + <p> + Most of the Osmiae of my region have none of the industry of their + kinswomen of the brambles, that is to say, they do not themselves prepare + the dwelling destined for the laying. They want ready-made lodgings, such + as the old cells and old galleries of Anthophorae and Chalicodomae. If + these favourite haunts are lacking, then a hiding-place in the wall, a + round hole in some bit of wood, the tube of a reed, the spiral of a dead + Snail under a heap of stones are adopted, according to the tastes of the + several species. The retreat selected is divided into chambers by + partition-walls, after which the entrance to the dwelling receives a + massive seal. That is the sum-total of the building done. + </p> + <p> + For this plasterer's rather than mason's work, the Horned and the + Three-horned Osmia employ soft earth. This material is different from the + Mason-bee's cement, which will withstand wind and weather for many years + on an exposed pebble; it is a sort of dried mud, which turns to pap on the + addition of a drop of water. The Mason-bee gathers her cementing-dust in + the most frequented and driest portions of the road; she wets it with a + saliva which, in drying, gives it the consistency of stone. The two Osmiae + who are the almond-tree's early visitors are no chemists: they know + nothing of the making and mixing of hydraulic mortar; they limit + themselves to gathering natural soaked earth, mud in short, which they + allow to dry without any special preparation on their part; and so they + need deep and well-sheltered retreats, into which the rain cannot + penetrate, or the work would fall to pieces. + </p> + <p> + While exploiting, in friendly rivalry with the Three-horned Osmia, the + galleries which the Mason-bee of the Sheds good-naturedly surrenders to + both, Latreille's Osmia uses different materials for her partitions and + her doors. She chews the leaves of some mucilaginous plant, some mallow + perhaps, and then prepares a sort of green putty with which she builds her + partitions and finally closes the entrance to the dwelling. When she + settles in the spacious cells of the Masked Anthophora (Anthophora + personata, ILLIG.), the entrance to the gallery, which is wide enough to + admit one's finger, is closed with a voluminous plug of this vegetable + paste. On the earthy banks, hardened by the sun, the home is then betrayed + by the gaudy colour of the lid. It is as though the authorities had closed + the door and affixed to it their great seals of green wax. + </p> + <p> + So far then as their building-materials are concerned, the Osmiae whom I + have been able to observe are divided into two classes: one building + compartments with mud, the other with a green-tinted vegetable putty. The + first section includes the Horned Osmia and the Three-horned Osmia, both + so remarkable for the horny tubercles on their faces. + </p> + <p> + The great reed of the south, the Arundo donax, is often used, in the + country, for rough garden-shelters against the mistral or just for fences. + These reeds, the ends of which are chopped off to make them all the same + length, are planted perpendicularly in the earth. I have often explored + them in the hope of finding Osmia-nests. My search has very seldom + succeeded. The failure is easily explained. The partitions and the + closing-plug of the Horned and of the Three-horned Osmia are made, as we + have seen, of a sort of mud which water instantly reduces to pap. With the + upright position of the reeds, the stopper of the opening would receive + the rain and would become diluted; the ceilings of the storeys would fall + in and the family would perish by drowning. Therefore the Osmia, who knew + of these drawbacks before I did, refuses the reeds when they are placed + perpendicularly. + </p> + <p> + The same reed is used for a second purpose. We make canisses of it, that + is to say, hurdles, which, in spring, serve for the rearing of silk-worms + and, in autumn, for the drying of figs. At the end of April and during + May, which is the time when the Osmiae work, the canisses are indoors, in + the silk-worm nurseries, where the Bee cannot take possession of them; in + autumn, they are outside, exposing their layers of figs and peeled peaches + to the sun; but by that time the Osmiae have long disappeared. If, + however, during the spring, an old, disused hurdle is left out of doors, + in a horizontal position, the Three-horned Osmia often takes possession of + it and makes use of the two ends, where the reeds lie truncated and open. + </p> + <p> + There are other quarters that suit the Three-horned Osmia, who is not + particular, it seems to me, and will make shift with any hiding-place, so + long as it has the requisite conditions of diameter, solidity, sanitation + and kindly darkness. The most original dwellings that I know her to occupy + are disused Snail-shells, especially the house of the Common Snail (Helix + aspersa). Let us go to the slope of the hills thick with olive-trees and + inspect the little supporting-walls which are built of dry stones and face + the south. In the crevices of this insecure masonry, we shall reap a + harvest of old Snail-shells, plugged with earth right up to the orifice. + The family of the Three-horned Osmia is settled in the spiral of those + shells, which is subdivided into chambers by mud partitions. + </p> + <p> + Let us inspect the stone-heaps, especially those which come from the + quarry-works. Here we often find the Field-mouse sitting on a grass + mattress, nibbling acorns, almonds, olive-stones and apricot-stones. The + Rodent varies his diet: to oily and farinaceous foods he adds the Snail. + When he is gone, he has left behind him, under the overhanging stones, + mixed up with the remains of other victuals, an assortment of empty + shells, sometimes plentiful enough to remind me of the heap of Snails + which, cooked with spinach and eaten country-fashion on Christmas Eve, are + flung away next day by the housewife. This gives the Three-horned Osmia a + handsome collection of tenements; and she does not fail to profit by them. + Then again, even if the Field-mouse's conchological museum be lacking, the + same broken stones serve as a refuge for Garden-snails who come to live + there and end by dying there. When we see Three-horned Osmiae enter the + crevices of old walls and of stone-heaps, there is no doubt about their + occupation: they are getting free lodgings out of the old Snail-shells of + those labyrinths. + </p> + <p> + The Horned Osmia, who is less common, might easily also be less ingenious, + that is to say, less rich in varieties of houses. She seems to scorn empty + shells. The only homes that I know her to inhabit are the reeds of the + hurdles and the deserted cells of the Masked Anthophora. + </p> + <p> + All the other Osmiae whose method of nest-building I know work with green + putty, a paste made of some crushed leaf or other; and none of them, + except Latreille's Osmia, is provided with the horned or tubercled armour + of the mud-kneaders. I should like to know what plants are used in making + the putty; probably each species has its own preferences and its little + professional secrets; but hitherto observation has taught me nothing + concerning these details. Whatever worker prepare it, the putty is very + much the same in appearance. When fresh, it is always a clear dark green. + Later, especially in the parts exposed to the air, it changes, no doubt + through fermentation, to the colour of dead leaves, to brown, to + dull-yellow; and the leafy character of its origin is no longer apparent. + But uniformity in the materials employed must not lead us to believe in + uniformity in the lodging; on the contrary, this lodging varies greatly + with the different species, though there is a marked predilection in + favour of empty shells. Thus Latreille's Osmia, together with the + Three-horned Osmia, uses the spacious structures of the Mason-bee of the + Sheds; she likes the magnificent cells of the Masked Anthophora; and she + is always ready to establish herself in the cylinder of any reed lying + flat on the ground. + </p> + <p> + I have already spoken of an Osmia (O. cyanoxantha, PEREZ) who elects to + make her home in the old nests of the Mason-bee of the Pebbles. (Cf. "The + Mason-bees": chapter 10.—Translator's Note.) Her closing-plug is + made of a stout concrete, consisting of fair-sized bits of gravel sunk in + the green paste; but for the inner partitions she employs only unalloyed + putty. As the outer door, situated on the curve of an unprotected dome, is + exposed to the inclemencies of the weather, the mother has to think of + fortifying it. Danger, no doubt, is the originator of that gritty + concrete. + </p> + <p> + The Golden Osmia (O. aurulenta, LATR.) absolutely insists on an empty + Snail-shell as her residence. The Brown or Girdled Snail, the Garden Snail + and especially the Common Snail, who has a more spacious spiral, all + scattered at random in the grass, at the foot of the walls and of the + sun-swept rocks, furnish her with her usual dwelling-house. Her dried + putty is a kind of felt full of short white hairs. It must come from some + hairy-leaved plant, one of the Boragineae perhaps, rich both in mucilage + and the necessary bristles. + </p> + <p> + The Red Osmia (O. rufo-hirta, LATR.) has a weakness for the Brown Snail + and the Garden Snail, in whose shells I find her taking refuge in April + when the north-wind blows. I am not yet much acquainted with her work, + which should resemble that of the Golden Osmia. + </p> + <p> + The Green Osmia (O. viridana, MORAWITZ) takes up her quarters, tiny + creature that she is, in the spiral staircase of Bulimulus radiatus. It is + a very elegant, but very small lodging, to say nothing of the fact that a + considerable portion is taken up with the green-putty plug. There is just + room for two. + </p> + <p> + The Andrenoid Osmia (O. andrenoides, LATR.), who looks so curious, with + her naked red abdomen, appears to build her nest in the shell of the + Common Snail, where I discover her refuged. + </p> + <p> + The Variegated Osmia (O. versicolor, LATR.) settles in the Garden Snail's + shell, almost right at the bottom of the spiral. + </p> + <p> + The Blue Osmia (O. cyanea, KIRB.) seems to me to accept many different + quarters. I have extracted her from old nests of the Mason-bee of the + Pebbles, from the galleries dug in a roadside bank by the Colletes (A + short-tongued Burrowing-bee known also as the Melitta.—Translator's + Note.) and lastly from the cavities made by some digger or other in the + decayed trunk of a willow-tree. + </p> + <p> + Morawitz' Osmia (O. Morawitzi, PEREZ) is not uncommon in the old nests of + the Mason-bee of the Pebbles, but I suspect her of favouring other + lodgings besides. + </p> + <p> + The Three-pronged Osmia (O. tridentata, DUF. and PER.) creates a home of + her own, digging herself a channel with her mandibles in dry bramble and + sometimes in danewort. It mixes a few scrapings of perforated pith with + the green paste. Its habits are shared by the Ragged Osmia (O. detrita, + PEREZ) and by the Tiny Osmia (O. parvula, DUF.) + </p> + <p> + The Chalicodoma works in broad daylight, on a tile, on a pebble, on a + branch in the hedge; none of her trade-practises is kept a secret from the + observer's curiosity. The Osmia loves mystery. She wants a dark retreat, + hidden from the eye. I would like, nevertheless, to watch her in the + privacy of her home and to witness her work with the same facility as if + she were nest-building in the open air. Perhaps there are some interesting + characteristics to be picked up in the depths of her retreats. It remains + to be seen whether my wish can be realized. + </p> + <p> + When studying the insect's mental capacity, especially its very retentive + memory for places, I was led to ask myself whether it would not be + possible to make a suitably-chosen Bee build in any place that I wished, + even in my study. And I wanted, for an experiment of this sort, not an + individual but a numerous colony. My preference leant towards the + Three-horned Osmia, who is very plentiful in my neighbourhood, where, + together with Latreille's Osmia, she frequents in particular the monstrous + nests of the Chalicodoma of the Sheds. I therefore thought out a scheme + for making the Three-horned Osmia accept my study as her settlement and + build her nests in glass tubes, through which I could easily watch the + progress. To these crystal galleries, which might well inspire a certain + distrust, were to be added more natural retreats: reeds of every length + and thickness and disused Chalicodoma-cells taken from among the biggest + and the smallest. A scheme like this sounds mad. I admit it, while + mentioning that perhaps none ever succeeded so well with me. We shall see + as much presently. + </p> + <p> + My method is extremely simple. All I ask is that the birth of my insects, + that is to say, their first seeing the light, their emerging from the + cocoon, should take place on the spot where I propose to make them settle. + Here there must be retreats of no matter what nature, but of a shape + similar to that in which the Osmia delights. The first impressions of + sight, which are the most long-lived of any, shall bring back my insects + to the place of their birth. And not only will the Osmiae return, through + the always open windows, but they will always nidify on the natal spot if + they find something like the necessary conditions. + </p> + <p> + And so, all through the winter, I collect Osmia-cocoons, picked up in the + nests of the Mason-bee of the Sheds; I go to Carpentras to glean a more + plentiful supply in the nests of the Hairy-footed Anthophora, that old + acquaintance whose wonderful cities I used to undermine when I was + studying the history of the Oil-beetles. (This study is not yet translated + into English; but cf. "The Life of the Fly": chapters 2 and 4.—Translator's + Note.) Later, at my request, a pupil and intimate friend of mine, M. Henri + Devillario, president of the civil court at Carpentras, sends me a case of + fragments broken off the banks frequented by the Hairy-footed Anthophora + and the Anthophora of the Walls, useful clods which furnish a handsome + adjunct to my collection. Indeed, at the end, I find myself with handfuls + of cocoons of the Three-horned Osmia. To count them would weary my + patience without serving any particular purpose. + </p> + <p> + I spread out my stock in a large open box on a table which receives a + bright diffused light but not the direct rays of the sun. The table stands + between two windows facing south and overlooking the garden. When the + moment of hatching comes, those two windows will always remain open to + give the swarm entire liberty to go in and out as it pleases. The glass + tubes and the reed-stumps are laid here and there, in fine disorder, close + to the heap of cocoons and all in a horizontal position, for the Osmia + will have nothing to do with upright reeds. The hatching of some of the + Osmiae will therefore take place under cover of the galleries destined to + be the building-yard later; and the site will be all the more deeply + impressed on their memory. When I have made these comprehensive + arrangements, there is nothing more to be done; and I wait patiently for + the building-season to open. + </p> + <p> + My Osmiae leave their cocoons in the second half of April. Under the + immediate rays of the sun, in well-sheltered nooks, the hatching would + occur a month earlier, as we can see from the mixed population of the + snowy almond-tree. The constant shade in my study has delayed the + awakening, without, however, making any change in the nesting-period, + which synchronizes with the flowering of the thyme. We now have, around my + working-table, my books, my jars and my various appliances, a buzzing + crowd that goes in and out of the windows at every moment. I enjoin the + household henceforth not to touch a thing in the insects' laboratory, to + do no more sweeping, no more dusting. They might disturb the swarm and + make it think that my hospitality was not to be trusted. I suspect that + the maid, wounded in her self-esteem at seeing so much dust accumulating + in the master's study, did not always respect my prohibitions and came in + stealthily, now and again, to give a little sweep of the broom. At any + rate, I came across a number of Osmiae who seemed to have been crushed + under foot while taking a sunbath on the floor in front of the window. + Perhaps it was I myself who committed the misdeed in a heedless moment. + There is no great harm done, for the population is a numerous one; and, + notwithstanding those crushed by inadvertence, notwithstanding the + parasites wherewith many of the cocoons are infested, notwithstanding + those who may have come to grief outside or been unable to find their way + back, notwithstanding the deduction of one-half which we must make for the + males: notwithstanding all this, during four or five weeks I witness the + work of a number of Osmiae which is much too large to allow of my watching + their individual operations. I content myself with a few, whom I mark with + different-coloured spots to distinguish them; and I take no notice of the + others, whose finished work will have my attention later. + </p> + <p> + The first to appear are the males. If the sun is bright, they flutter + around the heap of tubes as if to take careful note of the locality; blows + are exchanged and the rival swains indulge in mild skirmishing on the + floor, then shake the dust off their wings and fly away. I find them, + opposite my window, in the refreshment-bar of the lilac-bush, whose + branches bend with the weight of their scented panicles. Here the Bees get + drunk with sunshine and draughts of honey. Those who have had their fill + come home and fly assiduously from tube to tube, placing their heads in + the orifices to see if some female will at last make up her mind to + emerge. + </p> + <p> + One does, in point of fact. She is covered with dust and has the + disordered toilet that is inseparable from the hard work of the + deliverance. A lover has seen her, so has a second, likewise a third. All + crowd round her. The lady responds to their advances by clashing her + mandibles, which open and shut rapidly, several times in succession. The + suitors forthwith fall back; and they also, no doubt to keep up their + dignity, execute savage mandibular grimaces. Then the beauty retires into + the arbour and her wooers resume their places on the threshold. A fresh + appearance of the female, who repeats the play with her jaws; a fresh + retreat of the males, who do the best they can to flourish their own + pincers. The Osmiae have a strange way of declaring their passion: with + that fearsome gnashing of their mandibles, the lovers look as though they + meant to devour each other. It suggests the thumps affected by our yokels + in their moments of gallantry. + </p> + <p> + The ingenious idyll is soon over. By turns greeting and greeted with a + clash of jaws, the female leaves her gallery and begins impassively to + polish her wings. The rivals rush forward, hoist themselves on top of one + another and form a pyramid of which each struggles to occupy the base by + toppling over the favoured lover. He, however, is careful not to let go; + he waits for the strife overhead to calm down; and, when the + supernumeraries realize that they are wasting their time and throw up the + game, the couple fly away far from the turbulent rivals. This is all that + I have been able to gather about the Osmia's nuptials. + </p> + <p> + The females, who grow more numerous from day to day, inspect the premises; + they buzz outside the glass galleries and the reed dwellings; they go in, + stay for a while, come out, go in again and then fly away briskly into the + garden. They return, first one, then another. They halt outside, in the + sun, on the shutters fastened back against the wall; they hover in the + window-recess, come inside, go to the reeds and give a glance at them, + only to set off again and to return soon after. Thus do they learn to know + their home, thus do they fix their birthplace in their memory. The village + of our childhood is always a cherished spot, never to be effaced from our + recollection. The Osmia's life endures for a month; and she acquires a + lasting remembrance of her hamlet in a couple of days. 'Twas there that + she was born; 'twas there that she loved; 'tis there that she will return. + Dulces reminiscitur Argos. ('Now falling by another's wound, his eyes He + casts to heaven, on Argos thinks and dies.'—"Aeneid," Book 10 + Dryden's translation.) + </p> + <p> + At last each has made her choice. The work of construction begins; and my + expectations are fulfilled far beyond my wishes. The Osmiae build nests in + all the retreats which I have placed at their disposal. The glass tubes, + which I cover with a sheet of paper to produce the shade and mystery + favourable to concentrated toil, do wonderfully well. All, from first to + last, are occupied. The Osmiae quarrel for the possession of these crystal + palaces, hitherto unknown to their race. The reeds and the paper tubes + likewise do wonderfully. The number provided is too small; and I hasten to + increase it. Snail-shells are recognized as excellent abodes, though + deprived of the shelter of the stone-heap; old Chalicodoma-nests, down to + those of the Chalicodoma of the Shrubs (Cf. "The Mason-bees": chapters 4 + and 10.—Translator's Note.), whose cells are so small, are eagerly + occupied. The late-comers, finding nothing else free, go and settle in the + locks of my table-drawers. There are daring ones who make their way into + half-open boxes containing ends of glass tubes in which I have stored my + most recent acquisitions: grubs, pupae and cocoons of all kinds, whose + evolution I wished to study. Whenever these receptacles have an atom of + free space, they claim the right to build there, whereas I formally oppose + the claim. I hardly reckoned on such a success, which obliges me to put + some order into the invasion with which I am threatened. I seal up the + locks, I shut my boxes, I close my various receptacles for old nests, in + short I remove from the building-yard any retreat of which I do not + approve. And now, O my Osmiae, I leave you a free field! + </p> + <p> + The work begins with a thorough spring-cleaning of the home. Remnants of + cocoons, dirt consisting of spoilt honey, bits of plaster from broken + partitions, remains of dried Mollusc at the bottom of a shell: these and + much other insanitary refuse must first of all disappear. Violently the + Osmia tugs at the offending object and tears it out; and then off she + goes, in a desperate hurry, to dispose of it far away from the study. They + are all alike, these ardent sweepers: in their excessive zeal, they fear + lest they should block up the place with a speck of dust which they might + drop in front of the new house. The glass tubes, which I myself have + rinsed under the tap, are not exempt from a scrupulous cleaning. The Osmia + dusts them, brushes them thoroughly with her tarsi and then sweeps them + out backwards. What does she pick up? Not a thing. It makes no difference: + as a conscientious housewife, she gives the place a touch of the broom + nevertheless. + </p> + <p> + Now for the provisions and the partition-walls. Here the order of the work + changes according to the diameter of the cylinder. My glass tubes vary + greatly in dimensions. The largest have an inner width of a dozen + millimetres (Nearly half an inch.—Translator's Note.); the narrowest + measure six or seven. (About a quarter of an inch.—Translator's + Note.) In the latter, if the bottom suit her, the Osmia sets to work + bringing pollen and honey. If the bottom do not suit her, if the + sorghum-pith plug with which I have closed the rear-end of the tube be too + irregular and badly-joined, the Bee coats it with a little mortar. When + this small repair is made, the harvesting begins. + </p> + <p> + In the wider tubes, the work proceeds quite differently. At the moment + when the Osmia disgorges her honey and especially at the moment when, with + her hind-tarsi, she rubs the pollen-dust from her ventral brush, she needs + a narrow aperture, just big enough to allow of her passage. I imagine + that, in a straitened gallery, the rubbing of her whole body against the + sides gives the harvester a support for her brushing-work. In a spacious + cylinder, this support fails her; and the Osmia starts with creating one + for herself, which she does by narrowing the channel. Whether it be to + facilitate the storing of the victuals or for any other reason, the fact + remains that the Osmia housed in a wide tube begins with the partitioning. + </p> + <p> + Her division is made by a dab of clay placed at right angles to the axis + of the cylinder, at a distance from the bottom determined by the ordinary + length of a cell. This wad is not a complete round; it is more + crescent-shaped, leaving a circular space between it and one side of the + tube. Fresh layers are swiftly added to the dab of clay; and soon the tube + is divided by a partition which has a circular opening at the side of it, + a sort of dog-hole through which the Osmia will proceed to knead the + Bee-bread. When the victualling is finished and the egg laid upon the + heap, the hole is closed and the filled-up partition becomes the bottom of + the next cell. Then the same method is repeated, that is to say, in front + of the just completed ceiling a second partition is built, again with a + side-passage, which is stouter, owing to its distance from the centre, and + better able to withstand the numerous comings and goings of the housewife + than a central orifice, deprived of the direct support of the wall, could + hope to be. When this partition is ready, the provisioning of the second + cell is effected; and so on until the wide cylinder is completely stocked. + </p> + <p> + The building of this preliminary party-wall, with a narrow, round + dog-hole, for a chamber to which the victuals will not be brought until + later is not restricted to the Three-horned Osmia; it is also frequently + found in the case of the Horned Osmia and of Latreille's Osmia. Nothing + could be prettier than the work of the last-named, who goes to the plants + for her material and fashions a delicate sheet in which she cuts a + graceful arch. The Chinaman partitions his house with paper screens; + Latreille's Osmia divides hers with disks of thin green cardboard + perforated with a serving-hatch which remains until the room is completely + furnished. When we have no glass houses at our disposal, we can see these + little architectural refinements in the reeds of the hurdles, if we open + them at the right season. + </p> + <p> + By splitting the bramble-stumps in the course of July, we perceive also + that the Three-pronged Osmia, notwithstanding her narrow gallery, follows + the same practice as Latreille's Osmia, with a difference. She does not + build a party-wall, which the diameter of the cylinder would not permit; + she confines herself to putting up a frail circular pad of green putty, as + though to limit, before any attempt at harvesting, the space to be + occupied by the Bee-bread, whose depth could not be calculated afterwards + if the insect did not first mark out its confines. Can there really be an + act of measuring? That would be superlatively clever. Let us consult the + Three-horned Osmia in her glass tubes. + </p> + <p> + The Osmia is working at her big partition, with her body outside the cell + which she is preparing. From time to time, with a pellet of mortar in her + mandibles, she goes in and touches the previous ceiling with her forehead, + while the tip of her abdomen quivers and feels the pad in course of + construction. One might well say that she is using the length of her body + as a measure, in order to fix the next ceiling at the proper distance. + Then she resumes her work. Perhaps the measure was not correctly taken; + perhaps her memory, a few seconds old, has already become muddled. The Bee + once more ceases laying her plaster and again goes and touches the front + wall with her forehead and the back wall with the tip of her abdomen. + Looking at that body trembling with eagerness, extended to its full length + to touch the two ends of the room, how can we fail to grasp the + architect's grave problem? The Osmia is measuring; and her measure is her + body. Has she quite done, this time? Oh dear no! Ten times, twenty times, + at every moment, for the least particle of mortar which she lays, she + repeats her mensuration, never being quite certain that her trowel is + going just where it should. + </p> + <p> + Meanwhile, amid these frequent interruptions, the work progresses and the + partition gains in width. The worker is bent into a hook, with her + mandibles on the inner surface of the wall and the tip of her abdomen on + the outer surface. The soft masonry stands between the two points of + purchase. The insect thus forms a sort of rolling-press, in which the mud + wall is flattened and shaped. The mandibles tap and furnish mortar; the + end of the abdomen also pats and gives brisk trowel-touches. This anal + extremity is a builder's tool; I see it facing the mandibles on the other + side of the partition, kneading and smoothing it all over, flattening the + little lump of clay. It is a singular implement, which I should never have + expected to see used for this purpose. It takes an insect to conceive such + an original idea, to do mason's work with its behind! During this curious + performance, the only function of the legs is to keep the worker steady by + spreading out and clinging to the walls of the tunnel. + </p> + <p> + The partition with the hole in it is finished. Let us go back to the + measuring of which the Osmia was so lavish. What a magnificent argument in + favour of the reasoning-power of animals! To find geometry, the surveyor's + art, in an Osmia's tiny brain! An insect that begins by taking the + measurements of the room to be constructed, just as any master-builder + might do! Why, it's splendid, it's enough to cover with confusion those + horrible sceptics who persist in refusing to admit the animal's + 'continuous little flashes of atoms of reason!' + </p> + <p> + O common-sense, veil your face! It is with this gibberish about continuous + flashes of atoms of reason that men pretend to build up science to-day! + Very well, my masters; the magnificent argument with which I am supplying + you lacks but one little detail, the merest trifle: truth! Not that I have + not seen and plainly seen all that I am relating; but measuring has + nothing to do with the case. And I can prove it by facts. + </p> + <p> + If, in order to see the Osmia's nest as a whole, we split a reed + lengthwise, taking care not to disturb its contents; or, better still, if + we select for examination the string of cells built in a glass tube, we + are forthwith struck by one detail, namely, the uneven distances between + the partitions, which are placed almost at right angles to the axis of the + cylinder. It is these distances which fix the size of the chambers, which, + with a similar base, have different heights and consequently unequal + holding-capacities. The bottom partitions, the oldest, are farther apart; + those of the front part, near the orifice, are closer together. Moreover, + the provisions are plentiful in the loftier cells, whereas they are + niggardly and reduced to one-half or even one-third in the cells of lesser + height. + </p> + <p> + Here are a few examples of these inequalities. A glass tube with a + diameter of 12 millimetres (.468 inch.—Translator's Note.), inside + measurement, contains ten cells. The five lower ones, beginning with the + bottom-most, have as the respective distances between their partitions, in + millimetres: + </p> + <p> + 11, 12, 16, 13, 11. (.429,.468,.624,.507,.429 inch.—Translator's + Note.) + </p> + <p> + The five upper ones measure between their partitions: + </p> + <p> + 7, 7, 5, 6, 7. (.273,.273,.195,.234,.273 inch.—Translator's Note.) + </p> + <p> + A reed-stump 11 millimetres (.429 inch.—Translator's Note.) across + the inside contains fifteen cells; and the respective distances between + the partitions of those cells, starting from the bottom, are: + </p> + <p> + 13, 12, 12, 9, 9, 11, 8, 8, 7, 7, 7, 6, 6, 6, 7. (.507,.468,.468, + .351,.351,.429,.312,.312,.273,.273,.273,.234,.234,.234, .273 inch.—Translator's + Note.) + </p> + <p> + When the diameter of the tunnel is less, the partitions can be still + further apart, though they retain the general characteristic of being + closer to one another the nearer they are to the orifice. A reed of five + millimetres (.195 inch.—Translator's Note.) in diameter, gives me + the following distances, always starting from the bottom: + </p> + <p> + 22, 22, 20, 20, 12, 14. (.858,.858,.78,.78,.468,.546 inch.—Translator's + Note.) + </p> + <p> + Another, of 9 millimetres (.351 inch.—Translator's Note.), gives me: + </p> + <p> + 15, 14, 11, 10, 10, 9, 10. (.585,.546,.429,.39,.39,.351,.39 inch.—Translator's + Note.) + </p> + <p> + A glass tube of 8 millimetres (.312 inch.—Translator's Note.) + yields: + </p> + <p> + 15, 14, 20, 10, 10, 10. (.585,.546,.78,.39,.39,.39 inch.—Translator's + Note.). + </p> + <p> + I could fill pages and pages with such figures, if I cared to print all my + notes. Do they prove that the Osmia is a geometrician, employing a strict + measure based on the length of her body? Certainly not, because many of + those figures exceed the length of the insect; because sometimes a higher + number follows suddenly upon a lower; because the same string contains a + figure of one value and another figure of but half that value. They prove + only one thing: the marked tendency of the insect to shorten the distance + between the party-walls as the work proceeds. We shall see later that the + large cells are destined for the females and the small ones for the males. + </p> + <p> + Is there not at least a measuring adapted to each sex? Again, not so; for + in the first series, where the females are housed, instead of the interval + of 11 millimetres, which occurs at the beginning and the end, we find, in + the middle of the series, an interval of 16 millimetres, while in the + second series, reserved for the males, instead of the interval of 7 + millimetres at the beginning and the end, we have an interval of 5 + millimetres in the middle. It is the same with the other series, each of + which shows a striking discrepancy in its figures. If the Osmia really + studied the dimensions of her chambers and measured them with the + compasses of her body, how could she, with her delicate mechanism, fail to + notice mistakes of 5 millimetres, almost half her own length? + </p> + <p> + Besides, all idea of geometry vanishes if we consider the work in a tube + of moderate width. Here, the Osmia does not fix the front partition in + advance; she does not even lay its foundation. Without any boundary-pad, + with no guiding mark for the capacity of the cell, she busies herself + straightway with the provisioning. When the heap of Bee-bread is judged + sufficient, that is, I imagine, when her tired body tells her that she has + done enough harvesting, she closes up the chamber. In this case, there is + no measuring; and yet the capacity of the cell and the quantity of the + victuals fulfil the regular requirements of one or the other sex. + </p> + <p> + Then what does the Osmia do when she repeatedly stops to touch the front + partition with her forehead and the back partition, the one in the course + of building, with the tip of her abdomen? I have no idea what she does or + what she has in view. I leave the interpretation of this performance to + others, more venturesome than I. Plenty of theories are based on equally + shaky foundations. Blow on them and they sink into the quagmire of + oblivion. + </p> + <p> + The laying is finished, or perhaps the cylinder is full. A final partition + closes the last cell. A rampart is now built, at the orifice of the tube + itself, to forbid the ill-disposed all access to the home. This is a thick + plug, a massy work of fortification, whereon the Osmia spends enough + mortar to partition off any number of cells. A whole day is not too long + for making this barricade, especially in view of the minute + finishing-touches, when the Osmia fills up with putty every chink through + which the least atom could slip. The mason completing a wall smooths his + plaster and brings it to a fine surface while it is still wet; the Osmia + does the same, or almost. With little taps of the mandibles and a + continual shaking of her head, a sign of her zest for the work, she + smooths and polishes the surface of the lid for hours at a time. After + such pains, what foe could visit the dwelling? + </p> + <p> + And yet there is one, an Anthrax, A. sinuata (Cf. "The Life of the Fly": + chapters 2 and 4.—Translator's Note.), who will come later on, in + the height of summer, and succeed, invisible bit of thread that she is, in + making her way to the grub through the thickness of the door and the web + of the cocoon. In many cells, mischief of another kind has already been + done. During the progress of the works, an impudent Midge, one of the + Tachina-flies, who feeds her family on the victuals amassed by the Bee, + hovers in front of the galleries. Does she penetrate to the cells and lay + her eggs there in the mother's absence? I could never catch the sneak in + the act. Does she, like that other Tachina who ravages cells stocked with + game (The cells of the Hunting Wasps.—Translator's Note.), nimbly + deposit her eggs on the Osmia's harvest at the moment when the Bee is + going indoors? It is possible, though I cannot say for certain. The fact + remains that we soon see the Midge's grub-worms swarming around the larva, + the daughter of the house. There are ten, fifteen, twenty or more of them + gnawing with their pointed mouths at the common dish and turning the food + into a heap of fine, orange-coloured vermicelli. The Bee's grub dies of + starvation. It is life, life in all its ferocity even in these tiny + creatures. What an expenditure of ardent labour, of delicate cares, of + wise precautions, to arrive at...what? Her offspring sucked and drained + dry by the hateful Anthrax; her family sweated and starved by the infernal + Tachina. + </p> + <p> + The victuals consist mostly of yellow flour. In the centre of the heap, a + little honey is disgorged, which turns the pollen-dust into a firm, + reddish paste. On this paste the egg is laid, not flat, but upright, with + the fore-end free and the hind-end lightly held and fixed in the plastic + mass. When hatched, the young grub, kept in its place by its rear-end, + need only bend its neck a little to find the honey-soaked paste under its + mouth. When it grows stronger, it will release itself from its support and + eat up the surrounding flour. + </p> + <p> + All this is touching, in its maternal logic. For the new-born, dainty + bread-and-honey; for the adolescent, dry bread. In cases where the + provisions are all of a kind, these delicate precautions are superfluous. + The victuals of the Anthophorae and the Chalicodomae consist of flowing + honey, the same throughout. The egg is then laid at full length on the + surface, without any particular arrangement, thus compelling the new-born + grub to take its first mouthfuls at random. This has no drawback, as the + food is of the same quality throughout. But, with the Osmia's provisions—dry + powder on the edges, jam in the centre—the grub would be in danger + if its first meal were not regulated in advance. To begin with pollen not + seasoned with honey would be fatal to its stomach. Having no choice of its + mouthfuls because of its immobility and being obliged to feed on the spot + where it was hatched, the young grub must needs be born on the central + mass, where it has only to bend its head a little way in order to find + what its delicate stomach calls for. The place of the egg, therefore, + fixed upright by its base in the middle of the red jam, is most + judiciously chosen. What a contrast between this exquisite maternal + forethought and the horrible destruction by the Anthrax and the Midge! + </p> + <p> + The egg is rather large for the size of the Osmia. It is cylindrical, + slightly curved, rounded at both ends and transparent. It soon becomes + cloudy, while remaining diaphanous at each extremity. Fine lines, hardly + perceptible to the most penetrating lens, show themselves in transverse + circles. These are the first signs of segmentation. A contraction appears + in the front hyaline part, marking the head. An extremely thin opaque + thread runs down either side. This is the cord of tracheae communicating + between one breathing-hole and another. At last, the segments show + distinctly, with their lateral pads. The grub is born. + </p> + <p> + At first, one would think that there was no hatching in the proper sense + of the word—that is to say, no bursting and casting of a wrapper. + The most minute attention is necessary to show that appearances are + deceptive and that actually a fine membrane is thrown off from front to + back. This infinitesimal shred is the shell of the egg. + </p> + <p> + The grub is born. Fixed by its base, it curves into an arc and bends its + head, until now held erect, down to the red mass. The meal begins. Soon a + yellow cord occupying the front two-thirds of the body proclaims that the + digestive apparatus is swelling out with food. For a fortnight, consume + your provender in peace, my child; then spin your cocoon: you are now safe + from the Tachina! Shall you be safe from the Anthrax' sucker later on? + Alack! + </p> + <p> + <a name="link2HCH0003" id="link2HCH0003"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 3. THE DISTRIBUTION OF THE SEXES. + </h2> + <p> + Does the insect know beforehand the sex of the egg which it is about to + lay? When examining the stock of food in the cells just now, we began to + suspect that it does, for each little heap of provisions is carefully + proportioned to the needs at one time of a male and at another of a + female. What we have to do is to turn this suspicion into a certainty + demonstrated by experiment. And first let us find out how the sexes are + arranged. + </p> + <p> + It is not possible to ascertain the chronological order of a laying, + except by going to suitably-chosen species. Digging up the burrows of + Cerceris-, Bembex- or Philanthus-wasps will never tell us that this grub + has taken precedence of that in point of time nor enable us to decide + whether one cocoon in a colony belongs to the same family as another. To + compile a register of births is absolutely impossible here. Fortunately + there are a few species in which we do not find this difficulty: these are + the Bees who keep to one gallery and build their cells in storeys. Among + the number are the different inhabitants of the bramble-stumps, notably + the Three-pronged Osmiae, who form an excellent subject for observation, + partly because they are of imposing-size—bigger than any other + bramble-dwellers in my neighbourhood—partly because they are so + plentiful. + </p> + <p> + Let us briefly recall the Osmia's habits. Amid the tangle of a hedge, a + bramble-stalk is selected, still standing, but a mere withered stump. In + this the insect digs a more or less deep tunnel, an easy piece of work + owing to the abundance of soft pith. Provisions are heaped up right at the + bottom of the tunnel and an egg is laid on the surface of the food: that + is the first-born of the family. At a height of some twelve millimetres + (About half an inch.—Translator's Note.), a partition is fixed, + formed of bramble saw-dust and of a green paste obtained by masticating + particles of the leaves of some plant that has not yet been identified. + This gives a second storey, which in its turn receives provisions and an + egg, the second in order of primogeniture. And so it goes on, storey by + storey, until the cylinder is full. Then a thick plug of the same green + material of which the partitions are formed closes the home and keeps out + marauders. + </p> + <p> + In this common cradle, the chronological order of births is perfectly + clear. The first-born of the family is at the bottom of the series; the + last-born is at the top, near the closed door. The others follow from + bottom to top in the same order in which they followed in point of time. + The laying is numbered automatically; each cocoon tells us its respective + age by the place which it occupies. + </p> + <p> + To know the sexes, we must wait for the month of June. But it would be + unwise to postpone our investigations until that period. Osmia-nests are + not so common that we can hope to pick one up each time that we go out + with that object; besides, if we wait for the hatching-period before + examining the brambles, it may happen that the order has been disturbed + through some insects' having tried to make their escape as soon as + possible after bursting their cocoons; it may happen that the male Osmiae, + who are more forward than the females, are already gone. I therefore set + to work a long time beforehand and devote my leisure in winter to these + investigations. + </p> + <p> + The bramble-sticks are split and the cocoons taken out one by one and + methodically transferred to glass tubes, of approximately the same + diameter as the native cylinder. These cocoons are arranged one on top of + the other in exactly the same order that they occupied in the bramble; + they are separated from one another by a cotton plug, an insuperable + obstacle to the future insect. There is thus no fear that the contents of + the cells may become mixed or transposed; and I am saved the trouble of + keeping a laborious watch. Each insect can hatch at its own time, in my + presence or not: I am sure of always finding it in its place, in its + proper order, held fast fore and aft by the cotton barrier. A cork or + sorghum-pith partition would not fulfil the same purpose: the insect would + perforate it and the register of births would be muddled by changes of + position. Any reader wishing to undertake similar investigations will + excuse these practical details, which may facilitate his work. + </p> + <p> + We do not often come upon complete series, comprising the whole laying, + from the first-born to the youngest. As a rule, we find part of a laying, + in which the number of cocoons varies greatly, sometimes falling as low as + two, or even one. The mother has not deemed it advisable to confide her + whole family to a single bramble-stump; in order to make the exit less + toilsome, or else for reasons which escape me, she has left the first home + and elected to make a second home, perhaps a third or more. + </p> + <p> + We also find series with breaks in them. Sometimes, in cells distributed + at random, the egg has not developed and the provisions have remained + untouched, but mildewed; sometimes, the larva has died before spinning its + cocoon, or after spinning it. Lastly, there are parasites, such as the + Unarmed Zonitis (Zonitis mutica, one of the Oil-beetles.—Translator's + Note.) and the Spotted Sapyga (A Digger-wasp.—Translator's Note.), + who interrupt the series by substituting themselves for the original + occupant. All these disturbing factors make it necessary to examine a + large number of nests of the Three-pronged Osmia, if we would obtain a + definite result. + </p> + <p> + I have been studying the bramble-dwellers for seven or eight years and I + could not say how many strings of cocoons have passed through my hands. + During a recent winter, in view particularly of the distribution of the + sexes, I collected some forty of this Osmia's nests, transferred their + contents into glass tubes and made a careful summary of the sexes. I give + some of my results. The figures start in their order from the bottom of + the tunnel dug in the bramble and proceed upwards to the orifice. The + figure 1 therefore denotes the first-born of the series, the oldest in + date; the highest figure denotes the last-born. The letter M, placed under + the corresponding figure, represents the male and the letter F the female + sex. + </p> + <p> + 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 F F M F M F M M F F F F M F M + </p> + <p> + This is the longest series that I have ever been able to procure. It is + also complete, inasmuch as it comprises the entire laying of the Osmia. My + statement requires explaining, otherwise it would seem impossible to know + whether a mother whose acts one has not watched, nay more, whom one has + never seen, has or has not finished laying her eggs. The bramble-stump + under consideration leaves a free space of nearly four inches above the + continuous string of cocoons. Beyond it, at the actual orifice, is the + terminal stopper, the thick plug which closes the entrance to the gallery. + In this empty portion of the tunnel there is ample accommodation for + numerous cocoons. The fact that the mother has not made use of it proves + that her ovaries were exhausted; for it is exceedingly unlikely that she + has abandoned first-rate lodgings to go laboriously digging a new gallery + elsewhere and there continue her laying. + </p> + <p> + You may say that, if the unoccupied space marks the end of the laying, + nothing tells us that the beginning is actually at the bottom of the + cul-de-sac, at the other end of the tunnel. You may also say that the + laying is done in shifts, separated by intervals of rest. The space left + empty in the channel would mean that one of these shifts was finished and + not that there were no more eggs ripe for hatching. In answer to these + very plausible explanations, I will say that, the sum of my observations—and + they have been extremely numerous—is that the total number of eggs + laid not only by the Osmiae but by a host of other Bees fluctuates round + about fifteen. + </p> + <p> + Besides, when we consider that the active life of these insects lasts + hardly a month; when we remember that this period of activity is disturbed + by dark, rainy or very windy days, during which all work is suspended; + when lastly we ascertain, as I have done ad nauseam in the case of the + Three-horned Osmia, the time required for building and victualling a cell, + it becomes obvious that the total laying must be kept within narrow bounds + and that the mother has no time to lose if she wishes to get fifteen cells + satisfactorily built in three or four weeks interrupted by compulsory + rests. I shall give some facts later which will dispel your doubts, if any + remain. + </p> + <p> + I assume, therefore, that a number of eggs bordering on fifteen represents + the entire family of an Osmia, as it does of many other Bees. + </p> + <p> + Let us consult some other complete series. Here are two: + </p> + <p> + 1 2 3 4 5 6 7 8 9 10 11 12 13 F F M F M F M F F F F M F F M F F F M F F M + F M + </p> + <p> + In both cases, the laying is taken as complete, for the same reasons as + above. + </p> + <p> + We will end with some series that appear to me incomplete, in view of the + small number of cells and the absence of any free space above the pile of + cocoons: + </p> + <p> + 1 2 3 4 5 6 7 8 M M F M M M M M M M F M F M M M F M F F M M M M M F M F F + F F M M M F M + </p> + <p> + These examples are more than sufficient. It is quite evident that the + distribution of the sexes is not governed by any rule. All that I can say + on consulting the whole of my notes, which contain a good many instances + of complete layings—most of them, unfortunately, spoilt through gaps + caused by parasites, the death of the larva, the failure of the egg to + hatch and other accidents—all that I can say in general is that the + complete series begins with females and nearly always ends with males. The + incomplete series can teach us nothing in this respect, for they are only + fragments starting we know not whence; and it is impossible to tell + whether they should be ascribed to the beginning, to the end, or to an + intermediate period of the laying. To sum up: in the laying of the + Three-pronged Osmia, no order governs the succession of the sexes; only, + the series has a marked tendency to begin with females and to finish with + males. + </p> + <p> + The brambles, in my district, harbour two other Osmiae, both of much + smaller size: O. detrita, PEREZ, and O. parvula, DUF. The first is very + common, the second very rare; and until now I have found only one of her + nests, placed above a nest of O. detrita, in the same bramble. Here, + instead of the lack of order in the distribution of the sexes which we + find with O. tridentata, we have an order remarkable for consistency and + simplicity. I have before me the list of the series of O. detrita + collected last winter. Here are some of them: + </p> + <p> + 1. A series of twelve: seven females, beginning with the bottom of the + tunnel, and then five males. + </p> + <p> + 2. A series of nine: three females first, then six males. + </p> + <p> + 3. A series of eight: five females followed by three males. + </p> + <p> + 4. A series of eight: seven females followed by one male. + </p> + <p> + 5. A series of eight: one female followed by seven males. + </p> + <p> + 6. A series of seven: six females followed by one male. + </p> + <p> + The first series might very well be complete. The second and fifth appear + to be the end of layings, of which the beginning has taken place + elsewhere, in another bramble-stump. The males predominate and finish off + the series. Nos. 3, 4 and 6, on the other hand, look like the beginnings + of layings: the females predominate and are at the head of the series. + Even if these interpretations should be open to doubt, one result at least + is certain: with O. detrita, the laying is divided into two groups, with + no intermingling of the sexes; the first group laid yields nothing but + females, the second, or more recent, yields nothing but males. + </p> + <p> + What was only a sort of attempt with the Three-pronged Osmia—who, it + is true, begins with females and ends with males, but muddles up the order + and mixes the two sexes anyhow between the extreme points—becomes a + regular law with her kinswoman. The mother occupies herself at the start + with the stronger sex, the more necessary, the better-gifted, the female + sex, to which she devotes the first flush of her laying and the fullness + of her vigour; later, when she is perhaps already at the end of her + strength, she bestows what remains of her maternal solicitude upon the + weaker sex, the less-gifted, almost negligible male sex. + </p> + <p> + O. parvula, of whom I unfortunately possess but one series, repeats what + the previous witness has just shown us. This series, one of nine cocoons, + comprises five females followed by four males, without any mixing of the + sexes. + </p> + <p> + Next to these disgorgers of honey and gleaners of pollen-dust, it would be + well to consult other Hymenoptera, Wasps who devote themselves to the + chase and pile their cells one after the other, in a row, showing the + relative age of the cocoons. The brambles house several of these: Solenius + vagus, who stores up Flies; Psen atratus, who provides her grubs with a + heap of Plant-lice; Trypoxylon figulus, who feeds them with Spiders. + </p> + <p> + Solenius vagus digs her gallery in a bramble-stick that is lopped short, + but still fresh and green. The house of this Fly-huntress, therefore, + suffers from damp, as the sap enters, especially on the lower floors. This + seems to me rather insanitary. To avoid the humidity, or for other reasons + which escape me, the Solenius does not dig very far into her bramble-stump + and consequently can stack but a small number of cells in it. A series of + five cocoons gives me first four females and then one male; another + series, also of five, contains first three females, with two males + following. These are the most complete that I have for the moment. + </p> + <p> + I reckoned on the Black Psen, or Psen atratus, whose series are pretty + long; it is a pity that they are nearly always greatly interfered with by + a parasite called Ephialtes mediator. (Cf. "The Life of the Fly": chapter + 2.—Translator's Note.) I obtained only three series free from gaps: + one of eight cocoons, comprising only females; one of six, likewise + consisting wholly of females; lastly, one of eight, formed exclusively of + males. These instances seem to show that the Psen arranges her laying in a + succession of females and a succession of males; but they tell us nothing + of the relative order of the two series. + </p> + <p> + From the Spider-huntress, Trypoxylon figulus, I learnt nothing decisive. + She appeared to me to rove about from one bramble to the next, utilizing + galleries which she has not dug herself. Not troubling to be economical + with a lodging which it has cost her nothing to acquire, she carelessly + builds a few partitions at very unequal heights, stuffs three or four + compartments with Spiders and passes on to another bramble-stump, with no + reason, so far as I know, for abandoning the first. Her cells, therefore, + occur in series that are too short to give us any useful information. + </p> + <p> + This is all that the bramble-dwellers have to tell us; I have enumerated + the list of the principal ones in my district. We will now look into some + other Bees who arrange their cocoons in single files: the Megachiles (Cf. + Chapter 8 of the present volume.—Translator's Note.), who cut disks + out of leaves and fashion the disks into thimble-shaped receptacles; the + Anthidia (Cf. Chapters 9 and 10 of the present volume.—Translator's + Note.), who weave their honey-wallets out of cotton-wool and arrange their + cells one after the other in some cylindrical gallery. In most cases, the + home is the produce of neither the one nor the other. A tunnel in the + upright, earthy banks, the old work of some Anthophora, is the usual + dwelling. There is no great depth to these retreats; and all my searches, + zealously prosecuted during a number of winters, procured me only series + containing a small number of cocoons, four or five at most, often one + alone. And, what is quite as serious, nearly all these series are spoilt + by parasites and allow me to draw no well-founded deductions. + </p> + <p> + I remembered finding, at rare intervals, nests of both the Anthidium and + the Megachile in the hollows of cut reeds. I thereupon installed some + hives of a new kind on the sunniest walls of my enclosure. They consisted + of stumps of the great reed of the south, open at one end, closed at the + other by the natural knot and gathered into a sort of enormous pan-pipe, + such as Polyphemus might have employed. The invitation was accepted: + Osmiae, Anthidia and Megachiles came in fairly large numbers, especially + the first, to benefit by the queer installation. + </p> + <p> + In this way I obtained some magnificent series of Anthidia and Megachiles, + running up to a dozen. There was a melancholy side to this success. All my + series, with not one exception, were ravaged by parasites. Those of the + Megachile (M. sericans, FONSCOL), who fashions her goblets with robinia-, + holm-, and terebinth-leaves, were inhabited by Coelioxys octodentata (A + Parasitic Bee.—Translator's Note.); those of the Anthidium (A. + florentinum, LATR.) were occupied by a Leucopsis. Both kinds were swarming + with a colony of pigmy parasites whose name I have not yet been able to + discover. In short, my pan-pipe hives, though very useful to me from other + points of view, taught me nothing about the order of the sexes among the + Leaf-cutters and the cotton-weavers. + </p> + <p> + I was more fortunate with three Osmiae (O. tricornis, LATR., O. cornuta, + LATR., and O. Latreillii, SPIN.), all of whom gave me splendid results, + with reed-stumps arranged either against the walls of my garden, as I have + just said, or near their customary abode, the huge nests of the Mason-bee + of the Sheds. One of them, the Three-horned Osmia, did better still: as I + have described, she built her nests in my study, as plentifully as I could + wish, using reeds, glass tubes and other retreats of my selecting for her + galleries. + </p> + <p> + We will consult this last, who has furnished me with documents beyond my + fondest hopes, and begin by asking her of how many eggs her average laying + consists. Of the whole heap of colonized tubes in my study, or else out of + doors, in the hurdle-reeds and the pan-pipe appliances, the best-filled + contains fifteen cells, with a free space above the series, a space + showing that the laying is ended, for, if the mother had any more eggs + available, she would have lodged them in the room which she leaves + unoccupied. This string of fifteen appears to be rare; it was the only one + that I found. My attempts at indoor rearing, pursued during two years with + glass tubes or reeds, taught me that the Three-horned Osmia is not much + addicted to long series. As though to decrease the difficulties of the + coming deliverance, she prefers short galleries, in which only a part of + the laying is stacked. We must then follow the same mother in her + migration from one dwelling to the next if we would obtain a complete + census of her family. A spot of colour, dropped on the Bee's thorax with a + paint-brush while she is absorbed in closing up the mouth of the tunnel, + enables us to recognize the Osmia in her various homes. + </p> + <p> + In this way, the swarm that resided in my study furnished me, in the first + year, with an average of twelve cells. Next year, the summer appeared to + be more favourable and the average became rather higher, reaching fifteen. + The most numerous laying performed under my eyes, not in a tube, but in a + succession of Snail-shells, reached the figure of twenty-six. On the other + hand, layings of between eight and ten are not uncommon. Lastly, taking + all my records together, the result is that the family of the Osmia + fluctuates round about fifteen in number. + </p> + <p> + I have already spoken of the great differences in size apparent in the + cells of one and the same series. The partitions, at first widely spaced, + draw gradually nearer to one another as they come closer to the aperture, + which implies roomy cells at the back and narrow cells in front. The + contents of these compartments are no less uneven between one portion and + another of the string. Without any exception known to me, the large cells, + those with which the series starts, have more abundant provisions than the + straitened cells with which the series ends. The heap of honey and pollen + in the first is twice or even thrice as large as that in the second. In + the last cells, the most recent in date, the victuals are but a pinch of + pollen, so niggardly in amount that we wonder what will become of the + larva with that meagre ration. + </p> + <p> + One would think that the Osmia, when nearing the end of the laying, + attaches no importance to her last-born, to whom she doles out space and + food so sparingly. The first-born receive the benefit of her early + enthusiasm: theirs is the well-spread table, theirs the spacious + apartments. The work has begun to pall by the time that the last eggs are + laid; and the last-comers have to put up with a scurvy portion of food and + a tiny corner. + </p> + <p> + The difference shows itself in another way after the cocoons are spun. The + large cells, those at the back, receive the bulky cocoons; the small ones, + those in front, have cocoons only a half or a third as big. Before opening + them and ascertaining the sex of the Osmia inside, let us wait for the + transformation into the perfect insect, which will take place towards the + end of summer. If impatience gets the better of us, we can open them at + the end of July or in August. The insect is then in the nymphal stage; and + it is easy, under this form, to distinguish the two sexes by the length of + the antennae, which are larger in the males, and by the glassy + protuberances on the forehead, the sign of the future armour of the + females. Well, the small cocoons, those in the narrow front cells, with + their scanty store of provisions, all belong to males; the big cocoons, + those in the spacious and well-stocked cells at the back, all belong to + females. + </p> + <p> + The conclusion is definite: the laying of the Three-horned Osmia consists + of two distinct groups, first a group of females and then a group of + males. + </p> + <p> + With my pan-pipe apparatus displayed on the walls of my enclosure and with + old hurdle-reeds left lying flat out of doors, I obtained the Horned Osmia + in fair quantities. I persuaded Latreille's Osmia to build her nest in + reeds, which she did with a zeal which I was far from expecting. All that + I had to do was to lay some reed-stumps horizontally within her reach, in + the immediate neighbourhood of her usual haunts, namely, the nests of the + Mason-bee of the Sheds. Lastly, I succeeded without difficulty in making + her build her nests in the privacy of my study, with glass tubes for a + house. The result surpassed my hopes. + </p> + <p> + With both these Osmiae, the division of the gallery is the same as with + the Three-horned Osmia. At the back are large cells with plentiful + provisions and widely-spaced partitions; in front, small cells, with + scanty provisions and partitions close together. Also, the larger cells + supplied me with big cocoons and females; the smaller cells gave me little + cocoons and males. The conclusion therefore is exactly the same in the + case of all three Osmiae. + </p> + <p> + Before dismissing the Osmiae, let us devote a moment to their cocoons, a + comparison of which, in the matter of bulk, will furnish us with fairly + accurate evidence as to the relative size of the two sexes, for the thing + contained, the perfect insect, is evidently proportionate to the silken + wrapper in which it is enclosed. These cocoons are oval-shaped and may be + regarded as ellipsoids formed by a revolution around the major axis. The + volume of one of these solids is expressed in the following formula: + </p> + <p> + 4 / 3 x pi x a x (b squared), + </p> + <p> + in which 2a is the major axis and 2b the minor axis. + </p> + <p> + Now, the average dimensions of the cocoons of the Three-horned Osmia are + as follows: + </p> + <p> + 2a = 13 mm. (.507 inch.—Translator's Note.), 2b = 7 mm. (.273 inch.—Translator's + Note.) in the females; + </p> + <p> + 2a = 9 mm. (.351 inch.—Translator's Note.), 2b = 5 mm. (.195 inch.—Translator's + Note.) in the males. + </p> + <p> + The ratio therefore between 13 x 7 x 7 = 637 and 9 x 5 x 5 = 225 will be + more or less the ratio between the sizes of the two sexes. This ratio is + somewhere between 2 to 1 and 3 to 1. The females therefore are two or + three times larger than the males, a proportion already suggested by a + comparison of the mass of provisions, estimated simply by the eye. + </p> + <p> + The Horned Osmia gives us the following average dimensions: + </p> + <p> + 2a = 15 mm. (.585 inch.—Translator's Note.), 2b = 9 mm. (.351 inch.—Translator's + Note.) in the females; + </p> + <p> + 2a = 12 mm. (.468 inch.—Translator's Note.), 2b = 7 mm. (.273 inch.—Translator's + Note.) in the males. + </p> + <p> + Once again, the ratio between 15 x 9 x 9 = 1215 and 12 x 7 x 7 = 588 lies + between 2 to 1 and 3 to 1. + </p> + <p> + Besides the Bees who arrange their laying in a row, I have consulted + others whose cells are grouped in a way that makes it possible to + ascertain the relative order of the two sexes, though not quite so + precisely. One of these is the Mason-bee of the Walls. I need not describe + again her dome-shaped nest, built on a pebble, which is now so well-known + to us. (Cf. "The Mason-bees": chapter 1.—Translator's Note.) + </p> + <p> + Each mother chooses her stone and works on it in solitude. She is an + ungracious landowner and guards her site jealously, driving away any Mason + who even looks as though she might alight on it. The inhabitants of the + same nest are therefore always brothers and sisters; they are the family + of one mother. + </p> + <p> + Moreover, if the stone presents a large enough surface—a condition + easily fulfilled—the Mason-bee has no reason to leave the support on + which she began her laying and go in search of another whereon to deposit + the rest of her eggs. She is too thrifty of her time and of her mortar to + involve herself in such expenditure except for grave reasons. + Consequently, each nest, at least when it is new, when the Bee herself has + laid the first foundations, contains the entire laying. It is a different + thing when an old nest is restored and made into a place for depositing + the eggs. I shall come back later to such houses. + </p> + <p> + A newly-built nest then, with rare exceptions, contains the entire laying + of one female. Count the cells and we shall have the total list of the + family. Their maximum number fluctuates round about fifteen. The most + luxuriant series will occasionally reach as many as eighteen, though these + are very scarce. + </p> + <p> + When the surface of the stone is regular all around the site of the first + cell, when the mason can add to her building with the same facility in + every direction, it is obvious that the groups of cells, when finished, + will have the oldest in the central portion and the more recent in the + surrounding portion. Because of this juxtaposition of the cells, which + serve partly as a wall to those which come next, it is possible to form + some estimate of the chronological order of the cells in the Chalicodoma's + nest and thus to discover the sequence of the two sexes. + </p> + <p> + In winter, by which time the Bee has long been in the perfect state, I + collect Chalicodoma-nests, removing them bodily from their support with a + few smart sideward taps of the hammer on the pebbles. At the base of the + mortar dome the cells are wide agape and display their contents. I take + the cocoon from its box, open it and take note of the sex of the insect + enclosed. + </p> + <p> + I should probably be accused of exaggeration if I mentioned the total + number of the nests which I have gathered and the cells which I have + inspected by this method during the last six or seven years. I will + content myself with saying that the harvest of a single morning sometimes + consisted of as many as sixty nests of the Mason-bee. I had to have help + in carrying home my spoils, even though the nests were removed from their + stones on the spot. + </p> + <p> + From the enormous number of nests which I have examined, I am able to + state that, when the cluster is regular, the female cells occupy the + centre and the male cells the edges. Where the irregularity of the pebble + has prevented an even distribution around the initial point, the same rule + has been observed. A male cell is never surrounded on every side by female + cells: either it occupies the edges of the nest, or else it adjoins, at + least on some sides, other male cells, of which the last form part of the + exterior of the cluster. As the surrounding cells are obviously of a later + date than the inner cells, it follows that the Mason-bee acts like the + Osmiae: she begins her laying with females and ends it with males, each of + the sexes forming a series of its own, independent of the other. + </p> + <p> + Some further circumstances add their testimony to that of the surrounded + and surrounding cells. When the pebble projects sharply and forms a sort + of dihedral angle, one of whose faces is more or less vertical and the + other horizontal, this angle is a favourite site with the Mason, who thus + finds greater stability for her edifice in the support given her by the + double plane. These sites appear to me to be in great request with the + Chalicodoma, considering the number of nests which I find thus doubly + supported. In nests of this kind, all the cells, as usual, have their + foundations fixed to the horizontal surface; but the first row, the row of + cells first built, stands with its back against the vertical surface. + </p> + <p> + Well, these older cells, which occupy the actual edge of the dihedral + angle, are always female, with the exception of those at either end of the + row, which, as they belong to the outside, may be male cells. In front of + this first row come others. The female cells occupy the middle portion and + the male the ends. Finally, the last row, closing in the remainder, + contains only male cells. The progress of the work is very visible here: + the Mason has begun by attending to the central group of female cells, the + first row of which occupies the dihedral angle, and has finished her task + by distributing the male cells round the outside. + </p> + <p> + If the perpendicular face of the dihedral angle be high enough, it + sometimes happens that a second row of cells is placed above the first row + backing on to that plane; a third row occurs less often. The nest is then + one of several storeys. The lower storeys, the older, contain only + females; the upper, the more recent storey, contains none but males. It + goes without saying that the surface layer, even of the lower storeys, can + contain males without invalidating the rule, for this layer may always be + looked upon as the Chalicodoma's last work. + </p> + <p> + Everything therefore contributes to show that, in the Mason-bee, the + females take the lead in the order of primogeniture. Theirs is the central + and best-protected part of the clay fortress; the outer part, that most + exposed to the inclemencies of the weather and to accidents, is for the + males. + </p> + <p> + The males' cells do not differ from the females' only by being placed at + the outside of the cluster; they differ also in their capacity, which is + much smaller. To estimate the respective capacities of the two sorts of + cells, I go to work as follows: I fill the empty cell with very fine sand + and pour this sand back into a glass tube measuring 5 millimetres (.195 + inch.—Translator's Note.) in diameter. From the height of the column + of sand we can estimate the comparative capacity of the two kinds of + cells. I will take one at random among my numerous examples of cells thus + gauged. + </p> + <p> + It comprises thirteen cells and occupies a dihedral angle. The female + cells give me the following figures, in millimetres, as the height of the + columns of sand: + </p> + <p> + 40, 44, 43, 48, 48, 46, 47 (1.56, 1.71, 1.67, 1.87, 1.87, 1.79, 1.83 + inches.—Translator's Note.), + </p> + <p> + averaging 45. (1.75 inches.—Translator's Note.) + </p> + <p> + The male cells give me: + </p> + <p> + 32, 35, 28, 30, 30, 31 (1.24, 1.36, 1.09, 1.17, 1.17, 1.21 inches.—Translator's + Note.), + </p> + <p> + averaging 31. (1.21 inches.—Translator's Note.) + </p> + <p> + The ratio of the capacity of the cells for the two sexes is therefore + roughly a ratio of 4 to 3. The actual contents of the cell being + proportionate to its capacity, the above ratio must also be more or less + the ratio of provisions and sizes between females and males. These figures + will assist us presently to tell whether an old cell, occupied for a + second or third time, belonged originally to a female or a male. + </p> + <p> + The Chalicodoma of the Sheds cannot give us any information on this + matter. She builds under the same eaves, in excessively populous colonies; + and it is impossible to follow the labours of any single Mason, whose + cells, distributed here and there, are soon covered up with the work of + her neighbours. All is muddle and confusion in the individual output of + the swarming throng. + </p> + <p> + I have not watched the work of the Chalicodoma of the Shrubs with close + enough attention to be able to state definitely that this Bee is a + solitary builder. Her nest is a ball of clay hanging from a bough. + Sometimes, this nest is the size of a large walnut and then appears to be + the work of one alone; sometimes, it is the size of a man's fist, in which + case I have no doubt that it is the work of several. Those bulky nests, + comprising more than fifty cells, can tell us nothing exact, as a number + of workers must certainly have collaborated to produce them. + </p> + <p> + The walnut-sized nests are more trustworthy, for everything seems to + indicate that they were built by a single Bee. Here females are found in + the centre of the group and males at the circumference, in somewhat + smaller cells, thus repeating what the Mason-bee of the Pebbles has told + us. + </p> + <p> + One clear and simple rule stands out from this collection of facts. Apart + from the strange exception of the Three-pronged Osmia, who mixes the sexes + without any order, the Bees whom I studied and probably a crowd of others + produce first a continuous series of females and then a continuous series + of males, the latter with less provisions and smaller cells. This + distribution of the sexes agrees with what we have long known of the + Hive-bee, who begins her laying with a long sequence of workers, or + sterile females, and ends it with a long sequence of males. The analogy + continues down to the capacity of the cells and the quantities of + provisions. The real females, the Queen-bees, have wax cells incomparably + more spacious than the cells of the males and receive a much larger amount + of food. Everything therefore demonstrates that we are here in the + presence of a general rule. + </p> + <p> + But does this rule express the whole truth? Is there nothing beyond a + laying in two series? Are the Osmiae, the Chalicodomae and the rest of + them fatally bound by this distribution of the sexes into two distinct + groups, the male group following upon the female group, without any mixing + of the two? Is the mother absolutely powerless to make a change in this + arrangement, should circumstances require it? + </p> + <p> + The Three-pronged Osmia already shows us that the problem is far from + being solved. In the same bramble-stump, the two sexes occur very + irregularly, as though at random. Why this mixture in the series of + cocoons of a Bee closely related to the Horned Osmia and the Three-horned + Osmia, who stack theirs methodically by separate sexes in the hollow of a + reed? What the Bee of the brambles does cannot her kinswomen of the reeds + do too? Nothing, so far as I know, can explain this difference in a + physiological act of primary importance. The three Bees belong to the same + genus; they resemble one another in general outline, internal structure + and habits; and, with this close similarity, we suddenly find a strange + dissimilarity. + </p> + <p> + There is just one thing that might possibly arouse a suspicion of the + cause of this irregularity in the Three-pronged Osmia's laying. If I open + a bramble-stump in the winter to examine the Osmia's nest, I find it + impossible, in the vast majority of cases, to distinguish positively + between a female and a male cocoon: the difference in size is so small. + The cells, moreover, have the same capacity: the diameter of the cylinder + is the same throughout and the partitions are almost always the same + distance apart. If I open it in July, the victualling-period, it is + impossible for me to distinguish between the provisions destined for the + males and those destined for the females. The measurement of the column of + honey gives practically the same depth in all the cells. We find an equal + quantity of space and food for both sexes. + </p> + <p> + This result makes us foresee what a direct examination of the two sexes in + the adult form tells us. The male does not differ materially from the + female in respect of size. If he is a trifle smaller, it is scarcely + noticeable, whereas, in the Horned Osmia and the Three-horned Osmia, the + male is only half or a third the size of the female, as we have seen from + the respective bulk of their cocoons. In the Mason-bee of the Walls there + is also a difference in size, though less pronounced. + </p> + <p> + The Three-pronged Osmia has not therefore to trouble about adjusting the + dimensions of the dwelling and the quantity of the food to the sex of the + egg which she is about to lay; the measure is the same from one end of the + series to the other. It does not matter if the sexes alternate without + order: one and all will find what they need, whatever their position in + the row. The two other Osmiae, with their great disparity in size between + the two sexes, have to be careful about the twofold consideration of board + and lodging. And that, I think, is why they begin with spacious cells and + generous rations for the homes of the females and end with narrow, + scantily-provisioned cells, the homes of the males. With this sequence, + sharply defined for the two sexes, there is less fear of mistakes which + might give to one what belongs to another. If this is not the explanation + of the facts, I see no other. + </p> + <p> + The more I thought about this curious question, the more probable it + appeared to me that the irregular series of the Three-pronged Osmia and + the regular series of the other Osmiae, of the Chalicodomae and of the + Bees in general were all traceable to a common law. It seemed to me that + the arrangement in a succession first of females and then of males did not + account for everything. There must be something more. And I was right: + that arrangement in series is only a tiny fraction of the reality, which + is remarkable in a very different way. This is what I am going to prove by + experiment. + </p> + <p> + <a name="link2HCH0004" id="link2HCH0004"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 4. THE MOTHER DECIDES THE SEX OF THE EGG. + </h2> + <p> + I will begin with the Mason-bee of the Pebbles. (This is the same insect + as the Mason-bee of the Walls. Cf. "The Mason-bees": passim.—Translator's + Note.) The old nests are often used, when they are in good enough repair. + Early in the season the mothers quarrel fiercely over them; and, when one + of the Bees has taken possession of the coveted dome, she drives any + stranger away from it. The old house is far from being a ruin, only it is + perforated with as many holes as it once had occupants. The work of + restoration is no great matter. The heap of earth due to the destruction + of the lid by the outgoing tenant is taken out of the cell and flung away + at a distance, atom by atom. The remnants of the cocoon are also thrown + away, but not always, for the delicate silken wrapper sometimes adheres + closely to the masonry. + </p> + <p> + The victualling of the renovated cell is now begun. Next comes the laying; + and lastly the orifice is sealed with a mortar plug. A second cell is + utilized in the same way, followed by a third and so on, one after the + other, as long as any remain unoccupied and the mother's ovaries are not + exhausted. Finally, the dome receives, mainly over the apertures already + plugged, a coat of plaster which makes the nest look like new. If she has + not finished her laying, the mother goes in search of other old nests to + complete it. Perhaps she does not decide to found a new establishment + except when she can find no second-hand dwellings, which mean a great + economy of time and labour. In short, among the countless number of nests + which I have collected, I find many more ancient than recent ones. + </p> + <p> + How shall we distinguish one from the other? The outward aspect tells you + nothing, owing to the great care taken by the Mason to restore the surface + of the old dwelling equal to new. To resist the rigours of the winter, + this surface must be impregnable. The mother knows that and therefore + repairs the dome. Inside, it is another matter: the old nest stands + revealed at once. There are cells whose provisions, at least a year old, + are intact, but dried up or musty, because the egg has never developed. + There are others containing a dead larva, reduced by time to a blackened, + curled-up cylinder. There are some whence the perfect insect was never + able to issue: the Chalicodoma wore herself out in trying to pierce the + ceiling of her chamber; her strength failed her and she perished in the + attempt. Others again and very many are occupied by ravagers, Leucopses + (Cf. "The Mason-bees": chapter 11.—Translator's Note.) and + Anthrax-flies, who will come out a good deal later, in July. Altogether, + the house is far from having every room vacant; there are nearly always a + considerable number occupied either by parasites that were still in the + egg-stage at the time when the Mason-bee was at work or by damaged + provisions, dried grubs or Chalicodomae in the perfect state who have died + without being able to effect their deliverance. + </p> + <p> + Should all the rooms be available, a rare occurrence, there still remains + a method of distinguishing between an ancient nest and a recent one. The + cocoon, as I have said, adheres pretty closely to the walls; and the + mother does not always take away this remnant, either because she is + unable to do so, or because she considers the removal unnecessary. Thus + the base of the new cocoon is set in the bottom of the old cocoon. This + double wrapper points very clearly to two generations, two separate years. + I have even found as many as three cocoons fitting one into another at + their bases. Consequently, the nests of the Mason-bee of the Pebbles are + able to do duty for three years, if not more. Eventually they become utter + ruins, abandoned to the Spiders and to various smaller Bees or Wasps, who + take up their quarters in the crumbling rooms. + </p> + <p> + As we see, an old nest is hardly ever capable of containing the + Mason-bee's entire laying, which calls for some fifteen apartments. The + number of rooms at her disposal is most unequal, but always very small. It + is saying much when there are enough to receive about half the laying. + Four or five cells, sometimes two or even one: that is what the Mason + usually finds in a nest that is not her own work. This large reduction is + explained when we remember the numerous parasites that live upon the + unfortunate Bee. + </p> + <p> + Now, how are the sexes distributed in those layings which are necessarily + broken up between one old nest and another? They are distributed in such a + way as utterly to upset the idea of an invariable succession first of + females and then of males, the idea which occurs to us on examining the + new nests. If this rule were a constant one, we should be bound to find in + the old domes at one time only females, at another only males, according + as the laying was at its first or at its second stage. The simultaneous + presence of the two sexes would then correspond with the transition period + between one stage and the next and should be very unusual. On the + contrary, it is very common; and, however few cells there may be, we + always find both females and males in the old nests, on the sole condition + that the compartments have the regulation holding-capacity, a large + capacity for the females, a lesser for the males, as we have seen. + </p> + <p> + The old male cells can be recognized by their position on the outer edges + and by their capacity, measuring on an average the same as a column of + sand 31 millimetres high in a glass tube 5 millimetres wide. (1.21 x.195 + inches.—Translator's Note.) These cells contain males of the second + or third generation and none but males. In the old female cells, those in + the middle, whose capacity is measured by a similar column of sand 45 + millimetres high (1.75 inches.—Translator's Note.), are females and + none but females. + </p> + <p> + This presence of both sexes at a time, even when there are but two cells + free, one spacious and the other small, proves in the plainest fashion + that the regular distribution observed in the complete nests of recent + production is here replaced by an irregular distribution, harmonizing with + the number and holding-capacity of the chambers to be stocked. The + Mason-bee has before her, let me suppose, only five vacant cells: two + larger and three smaller. The total space at her disposal would do for + about a third of the laying. Well, in the two large cells, she puts + females; in the three small cells, she puts males. + </p> + <p> + As we find the same sort of thing in all the old nests, we must needs + admit that the mother knows the sex of the egg which she is going to lay, + because that egg is placed in a cell of the proper capacity. We can go + further and admit that the mother alters the order of succession of the + sexes at her pleasure, because her layings, between one old nest and + another, are broken up into small groups of males and females according to + the exigencies of space in the actual nest which she happens to be + occupying. + </p> + <p> + Just now, in the new nest, we saw the Mason-bee arranging her total laying + into series first of females and next of males; and here she is, mistress + of an old nest of which she has not the power to alter the arrangement, + breaking up her laying into sections comprising both sexes just as + required by the conditions imposed upon her. She therefore decides the sex + of the egg at will, for, without this prerogative, she could not, in the + chambers of the nest which she owes to chance, deposit unerringly the sex + for which those chambers were originally built; and this happens however + small the number of chambers to be filled. + </p> + <p> + When the nest is new, I think I see a reason why the Mason-bee should + seriate her laying into females and then males. Her nest is a half-sphere. + That of the Mason-bee of the Shrubs is very nearly a sphere. Of all + shapes, the spherical shape is the strongest. Now these two nests require + an exceptional power of resistance. Without protection of any kind, they + have to brave the weather, one on its pebble, the other on its bough. + Their spherical configuration is therefore very practical. + </p> + <p> + The nest of the Mason-bee of the Walls consists of a cluster of upright + cells backing against one another. For the whole to take a spherical form, + the height of the chambers must diminish from the centre of the dome to + the circumference. Their elevation is the sine of the meridian arc + starting from the plane of the pebble. Therefore, if they are to have any + solidity, there must be large cells in the middle and small cells at the + edges. And, as the work begins with the central chambers and ends with + those on the circumference, the laying of the females, destined for the + large cells, must precede that of the males, destined for the small cells. + So the females come first and the males at the finish. + </p> + <p> + This is all very well when the mother herself founds the dwelling, when + she lays the first rows of bricks. But, when she is in the presence of an + old nest, of which she is quite unable to alter the general arrangement, + how is she to make use of the few vacant rooms, the large and the small + alike, if the sex of the egg be already irrevocably fixed? She can only do + so by abandoning the arrangement in two consecutive rows and accommodating + her laying to the varied exigencies of the home. Either she finds it + impossible to make an economical use of the old nest, a theory refuted by + the evidence, or else she determines at will the sex of the egg which she + is about to lay. + </p> + <p> + The Osmiae themselves will furnish the most conclusive evidence on the + latter point. We have seen that these Bees are not generally miners, who + themselves dig out the foundation of their cells. They make use of the old + structures of others, or else of natural retreats, such as hollow stems, + the spirals of empty shells and various hiding-places in walls, clay or + wood. Their work is confined to repairs to the house, such as partitions + and covers. There are plenty of these retreats; and the insect would + always find first-class ones if it thought of going any distance to look + for them. But the Osmia is a stay-at-home: she returns to her birth-place + and clings to it with a patience extremely difficult to exhaust. It is + here, in this little familiar corner, that she prefers to settle her + progeny. But then the apartments are few in number and of all shapes and + sizes. There are long and short ones, spacious ones and narrow. Short of + expatriating herself, a Spartan course, she has to use them all, from + first to last, for she has no choice. Guided by these considerations, I + embarked on the experiments which I will now describe. + </p> + <p> + I have said how my study, on two separate occasions, became a populous + hive, in which the Three-horned Osmia built her nests in the various + appliances which I had prepared for her. Among these appliances, tubes, + either of glass or reed, predominated. There were tubes of all lengths and + widths. In the long tubes, entire or almost entire layings, with a series + of females followed by a series of males, were deposited. As I have + already referred to this result, I will not discuss it again. The short + tubes were sufficiently varied in length to lodge one or other portion of + the total laying. Basing my calculations on the respective lengths of the + cocoons of the two sexes, on the thickness of the partitions and the final + lid, I shortened some of these to the exact dimensions required for two + cocoons only, of different sexes. + </p> + <p> + Well, these short tubes, whether of glass or reed, were seized upon as + eagerly as the long tubes. Moreover, they yielded this splendid result: + their contents, only a part of the total laying, always began with female + and ended with male cocoons. This order was invariable; what varied was + the number of cells in the long tubes and the proportion between the two + sorts of cocoons, sometimes males predominating and sometimes females. + </p> + <p> + The experiment is of paramount importance; and it will perhaps make the + result clearer if I quote one instance from among a multitude of similar + cases. I give the preference to this particular instance because of the + rather exceptional fertility of the laying. An Osmia marked on the thorax + is watched, day by day, from the commencement to the end of her work. From + the 1st to the 10th of May, she occupies a glass tube in which she lodges + seven females followed by a male, which ends the series. From the 10th to + the 17th of May, she colonizes a second tube, in which she lodges first + three females and then three males. From the 17th to the 25th of May, a + third tube, with three females and then two males. On the 26th of May, a + fourth tube, which she abandons, probably because of its excessive width, + after laying one female in it. Lastly, from the 26th to the 30th of May, a + fifth tube, which she colonizes with two females and three males. Total: + twenty-five Osmiae, including seventeen females and eight males. And it + will not be superfluous to observe that these unfinished series do not in + any way correspond with periods separated by intervals of rest. The laying + is continuous, in so far as the variable condition of the atmosphere + allows. As soon as one tube is full and closed, another is occupied by the + Osmia without delay. + </p> + <p> + The tubes reduced to the exact length of two cells fulfilled my + expectation in the great majority of cases: the lower cell was occupied by + a female and the upper by a male. There were a few exceptions. More + discerning than I in her estimate of what was strictly necessary, + better-versed in the economy of space, the Osmia had found a way of + lodging two females where I had only seen room for one female and a male. + </p> + <p> + This experiment speaks volumes. When confronted with tubes too small to + receive all her family, she is in the same plight as the Mason-bee in the + presence of an old nest. She thereupon acts exactly as the Chalicodoma + does. She breaks up her laying, divides it into series as short as the + room at her disposal demands; and each series begins with females and ends + with males. This breaking up, on the one hand, into sections in all of + which both sexes are represented and the division, on the other hand, of + the entire laying into just two groups, one female, the other male, when + the length of the tube permits, surely provide us with ample evidence of + the insect's power to regulate the sex of the egg according to the + exigencies of space. + </p> + <p> + And besides the exigencies of space one might perhaps venture to add those + connected with the earlier development of the males. These burst their + cocoons a couple of weeks or more before the females; they are the first + who hasten to the sweets of the almond-tree. In order to release + themselves and emerge into the glad sunlight without disturbing the string + of cocoons wherein their sisters are still sleeping, they must occupy the + upper end of the row; and this, no doubt, is the reason that makes the + Osmia end each of her broken layings with males. Being next to the door, + these impatient ones will leave the home without upsetting the shells that + are slower in hatching. + </p> + <p> + I experimented on Latreille's Osmia, using short and even very short + stumps of reed. All that I had to do was to lay them just beside the nests + of the Mason-bee of the Sheds, nests beloved by this particular Osmia. + Old, disused hurdles supplied me with reeds inhabited from end to end by + the Horned Osmia. In both cases I obtained the same results and the same + conclusions as with the Three-horned Osmia. + </p> + <p> + I return to the latter, nidifying under my eyes in some old nests of the + Mason-bee of the Walls, which I had placed within her reach, mixed up with + the tubes. Outside my study, I had never yet seen the Three-horned Osmia + adopt that domicile. This may be due to the fact that these nests are + isolated one by one in the fields; and the Osmia, who loves to feel + herself surrounded by her kin and to work in plenty of company, refuses + them because of this isolation. But on my table, finding them close to the + tubes in which the others are working, she adopts them without hesitation. + </p> + <p> + The chambers presented by those old nests are more or less spacious + according to the thickness of the coat of mortar which the Chalicodoma has + laid over the assembled chambers. To leave her cell, the Mason-bee has to + perforate not only the plug, the lid built at the mouth of the cell, but + also the thick plaster wherewith the dome is strengthened at the end of + the work. The perforation results in a vestibule which gives access to the + chamber itself. It is this vestibule which is sometimes longer and + sometimes shorter, whereas the corresponding chamber is of almost constant + dimensions, in the case of the same sex, of course. + </p> + <p> + We will first consider the short vestibule, at the most large enough to + receive the plug with which the Osmia will close up the lodging. There is + then nothing at her disposal except the cell proper, a spacious apartment + in which one of the Osmia's females will find ample accommodation, for she + is much smaller than the original occupant of the chamber, no matter the + sex; but there is not room for two cocoons at a time, especially in view + of the space taken up by the intervening partition. Well, in those large, + well-built chambers, formerly the homes of Chalicodomae, the Osmia settles + females and none but females. + </p> + <p> + Let us now consider the long vestibule. Here, a partition is constructed, + encroaching slightly on the cell proper, and the residence is divided into + two unequal storeys, a large room below, housing a female, and a narrow + cabin above, containing a male. + </p> + <p> + When the length of the vestibule permits, allowing for the space required + by the outer stopper, a third storey is built, smaller than the second; + and another male is lodged in this cramped corner. In this way the old + nest of the Mason-bee of the Pebbles is colonized, cell after cell, by a + single mother. + </p> + <p> + The Osmia, as we see, is very frugal of the lodging that has fallen to her + share; she makes the best possible use of it, giving to the females the + spacious chambers of the Mason-bee and to the males the narrow vestibules, + subdivided into storeys when this is feasible. Economy of space is the + chief consideration, since her stay-at-home tastes do not allow her to + indulge in distant quests. She has to employ the site which chance places + at her disposal just as it is, now for a male and now for a female. Here + we see displayed, more clearly than ever, her power of deciding the sex of + the egg, in order to adapt it judiciously to the conditions of the + house-room available. + </p> + <p> + I had offered at the same time to the Osmiae in my study some old nests of + the Mason-bee of the Shrubs, which are clay spheroids with cylindrical + cavities in them. These cavities are formed, as in the old nests of the + Mason-bee of the Pebbles, of the cell properly so-called and of the + exit-way which the perfect insect cut through the outer coating at the + time of its deliverance. Their diameter is about seven millimetres (.273 + inch.—Translator's Note.); their depth at the centre of the heap is + 23 millimetres (.897 inch.—Translator's Note.); and at the edge + averages 14 millimetres (.546 inch.—Translator's Note.) + </p> + <p> + The deep central cells receive only the females of the Osmia; sometimes + even the two sexes together, with a partition in the middle, the female + occupying the lower and the male the upper storey. True, in such cases + economy of space is strained to the utmost, the apartments provided by the + Mason-bee of the Shrubs being very small as it is, despite their + entrance-halls. Lastly, the deeper cavities on the circumference are + allotted to females and the shallower to males. + </p> + <p> + I will add that a single mother peoples each nest and also that she + proceeds from cell to cell without troubling to ascertain the depth. She + goes from the centre to the edges, from the edges to the centre, from a + deep cavity to a shallow cavity and vice versa, which she would not do if + the sexes were to follow upon each other in a settled order. For greater + certainty, I numbered the cells of one nest as each of them was closed. On + opening them later, I was able to see that the sexes were not subjected to + a chronological arrangement. Females were succeeded by males and these by + females without its being possible for me to make out any regular + sequence. Only—and this is the essential point—the deep + cavities were allotted to the females and the shallow ones to the males. + </p> + <p> + We know that the Three-horned Osmia prefers to haunt the habitations of + the Bees who nidify in populous colonies, such as the Mason-bee of the + Sheds and the Hairy-footed Anthophora. Exercising the very greatest care, + I broke up some great lumps of earth removed from the banks inhabited by + the Anthophora and sent to me from Carpentras by my dear friend and pupil + M. Devillario. I examined them conscientiously in the quiet of my study. I + found the Osmia's cocoons arranged in short series, in very irregular + passages, the original work of which is due to the Anthophora. Touched up + afterwards, made larger or smaller, lengthened or shortened, intersected + with a network of crossings by the numerous generations that had succeeded + one another in the same city, they formed an inextricable labyrinth. + </p> + <p> + Sometimes these corridors did not communicate with any adjoining + apartment; sometimes they gave access to the spacious chamber of the + Anthophora, which could be recognized, in spite of its age, by its oval + shape and its coating of glazed stucco. In the latter case, the bottom + cell, which once constituted, by itself, the chamber of the Anthophora, + was always occupied by a female Osmia. Beyond it, in the narrow corridor, + a male was lodged, not seldom two, or even three. Of course, clay + partitions, the work of the Osmia, separated the different inhabitants, + each of whom had his own storey, his own closed cell. + </p> + <p> + When the accommodation consisted of no more than a simple cylinder, with + no state-bedroom at the end of it—a bedroom always reserved for a + female—the contents varied with the diameter of the cylinder. The + series, of which the longest were series of four, included, with a wider + diameter, first one or two females, then one or two males. It also + happened, though rarely, that the series was reversed, that is to say, it + began with males and ended with females. Lastly, there were a good many + isolated cocoons, of one sex or the other. When the cocoon was alone and + occupied the Anthophora's cell, it invariably belonged to a female. + </p> + <p> + I have observed the same thing in the nests of the Mason-bee of the Sheds, + but not so easily. The series are shorter here, because the Mason-bee does + not bore galleries but builds cell upon cell. The work of the whole swarm + thus forms a stratum of cells that grows thicker from year to year. The + corridors occupied by the Osmia are the holes which the Mason-bee dug in + order to reach daylight from the deep layers. In these short series, both + sexes are usually present; and, if the Mason-bee's chamber is at the end + of the passage, it is inhabited by a female Osmia. + </p> + <p> + We come back to what the short tubes and the old nests of the Mason-bee of + the Pebbles have already taught us. The Osmia who, in tubes of sufficient + length, divides her whole laying into a continuous sequence of females and + a continuous sequence of males, now breaks it up into short series in + which both sexes are present. She adapts her sectional layings to the + exigencies of a chance lodging; she always places a female in the + sumptuous chamber which the Mason-bee or the Anthophora occupied + originally. + </p> + <p> + Facts even more striking are supplied by the old nests of the Masked + Anthophora (A. personata, ILLIG.), old nests which I have seen utilized by + the Horned Osmia and the Three-horned Osmia at the same time. Less + frequently, the same nests serve for Latreille's Osmia. Let us first + describe the Masked Anthophora's nests. + </p> + <p> + In a steep bank of sandy clay, we find a set of round, wide-open holes. + There are generally only a few of them, each about half an inch in + diameter. They are the entrance-doors leading to the Anthophora's abode, + doors always left open, even after the building is finished. Each of them + gives access to a short passage, sometimes straight, sometimes winding, + nearly horizontal, polished with minute care and varnished with a sort of + white glaze. It looks as if it had received a thin coat of whitewash. On + the inner surface of this passage, in the thickness of the earthy bank, + spacious oval niches have been excavated, communicating with the corridor + by means of a narrow bottle-neck, which is closed, when the work is done, + with a substantial mortar stopper. The Anthophora polishes the outside of + this stopper so well, smooths its surface so perfectly, bringing it to the + same level as that of the passage, is so careful to give it the white tint + of the rest of the wall that, when the job is finished, it becomes + absolutely impossible to distinguish the entrance-door corresponding with + each cell. + </p> + <p> + The cell is an oval cavity dug in the earthy mass. The wall has the same + polish, the same chalky whiteness as the general passage. But the + Anthophora does not limit herself to digging oval niches: to make her work + more solid, she pours over the walls of the chamber a salivary liquid + which not only whitens and varnishes but also penetrates to a depth of + some millimetres into the sandy earth, which it turns into a hard cement. + A similar precaution is taken with the passage; and therefore the whole is + a solid piece of work capable of remaining in excellent condition for + years. + </p> + <p> + Moreover, thanks to the wall hardened by the salivary fluid, the structure + can be removed from its matrix by chipping it carefully away. We thus + obtain, at least in fragments, a serpentine tube from which hangs a single + or double row of oval nodules that look like large grapes drawn out + lengthwise. Each of these nodules is a cell, the entrance to which, + carefully hidden, opens into the tube or passage. When she wishes to leave + her cell, in the spring, the Anthophora destroys the mortar disk that + closes the jar and thus reaches the general corridor, which is quite open + to the outer air. The abandoned nest provides a series of pear-shaped + cavities, of which the distended part is the old cell and the contracted + part the exit-neck, rid of its stopper. + </p> + <p> + These pear-shaped hollows form splendid lodgings, impregnable strongholds, + in which the Osmiae find a safe and commodious retreat for their families. + The Horned Osmia and the Three-horned Osmia establish themselves there at + the same time. Although it is a little too large for her, Latrielle's + Osmia also appears very well satisfied with it. + </p> + <p> + I have examined some forty of the superb cells utilized by each of the + first two. The great majority are divided into two storeys by means of a + transversal partition. The lower storey includes the larger portion of the + Anthophora's cell; the upper storey includes the rest of the cell and a + little of the bottle-neck that surmounts it. The two-roomed dwelling is + closed, in the passage, by a shapeless, bulky mass of dried mud. What a + clumsy artist the Osmia is, compared with the Anthophora! Against the + exquisite work of the Anthophora, partition and plug strike a note as + hideously incongruous as a lump of dirt on polished marble. + </p> + <p> + The two apartments thus obtained are of a very unequal capacity, which at + once strikes the observer. I measured them with my five-millimetre tube. + On an average, the bottom one is represented by a column of sand 50 + millimetres deep (1.95 inches.—Translator's Note.) and the top one + by a column of 15 millimetres (.585 inch.—Translator's Note.). The + holding-capacity of the one is therefore about three times as large as + that of the other. The cocoons enclosed present the same disparity. The + bottom one is big, the top one small. Lastly, the lower one belongs to a + female Osmia and the upper to a male Osmia. + </p> + <p> + Occasionally the length of the bottle-neck allows of a fresh arrangement + and the cavity is divided into three storeys. The bottom one, which is + always the most spacious, contains a female; the two above, both smaller + than the first and one smaller than the other, contain males. + </p> + <p> + Let us keep to the first case, which is always the most frequent. The + Osmia is in the presence of one of these pear-shaped hollows. It is a find + that must be employed to the best advantage: a prize of this sort is rare + and falls only to fortune's favourites. To lodge two females in it at once + is impossible; there is not sufficient room. To lodge two males in it + would be undue generosity to a sex that is entitled to but the smallest + consideration. Besides, the two sexes must be represented in almost equal + numbers. The Osmia decides upon one female, whose portion shall be the + better room, the lower one, which is larger, better-protected and more + nicely polished, and one male, whose portion shall be the upper storey, a + cramped attic, uneven and rugged in the part which encroaches on the + bottle-neck. This decision is proved by numerous undeniable facts. Both + Osmiae therefore can choose the sex of the egg about to be laid, seeing + that they are now breaking up the laying into groups of two, a female and + a male, as required by the conditions of the lodging. + </p> + <p> + I have only once found Latreille's Osmia established in the nest of the + Masked Anthophora. She had occupied but a small number of cells, because + the others were not free, being inhabited by the Anthophora. The cells in + question were divided into three storeys by partitions of green mortar; + the lower storey was occupied by a female, the two others by males, with + smaller cocoons. + </p> + <p> + I came to an even more remarkable example. Two Anthidia of my district, A. + septemdentatum, LATR., and A. bellicosum, LEP., adopt as the home of their + offspring the empty shells of different snails: Helix aspersa, H. algira, + H. nemoralis, H. caespitum. The first-named, the Common Snail, is the most + often used, under the stone-heaps and in the crevices of old walls. Both + Anthidia colonize only the second whorl of the spiral. The central part is + too small and remains unoccupied. Even so with the front whorl, the + largest, which is left completely empty, so much so that, on looking + through the opening, it is impossible to tell whether the shell does or + does not contain the Bee's nest. We have to break this last whorl if we + would perceive the curious nest tucked away in the spiral. + </p> + <p> + We then find first a transversal partition, formed of tiny bits of gravel + cemented by a putty made from resin, which is collected in fresh drops + from the oxycedrus and the Aleppo pine. Beyond this is a stout barricade + made up of rubbish of all kinds: bits of gravel, scraps of earth, + juniper-needles, the catkins of the conifers, small shells, dried + excretions of Snails. Next come a partition of pure resin, a large cocoon + in a roomy chamber, a second partition of pure resin and, lastly, a + smaller cocoon in a narrow chamber. The inequality of the two cells is the + necessary consequence of the shape of the shell, whose inner space gains + rapidly in width as the spiral gets nearer to the orifice. Thus, by the + mere general arrangement of the home and without any work on the Bee's + part beyond some slender partitions, a large room is marked out in front + and a much smaller room at the back. + </p> + <p> + By a very remarkable exception, which I have mentioned casually elsewhere, + the males of the genus Anthidium are generally larger than the females; + and this is the case with the two species in particular that divide the + Snail's spiral with resin partitions. I collected some dozens of nests of + both species. In at least half the cases, the two sexes were present + together; the female, the smaller, occupied the front cell and the male, + the bigger, the back cell. Other cells, which were smaller or too much + obstructed at the back by the dried-up remains of the Mollusc, contained + only one cell, occupied at one time by a female and at another by a male. + A few, lastly, had both cells inhabited now by two males and now by two + females. The most frequent arrangement was the simultaneous presence of + both sexes, with the female in front and the male behind. The Anthidia who + make resin-dough and live in Snail-shells can therefore alternate the + sexes regularly to meet the exigencies of the spiral dwelling-house. + </p> + <p> + One more thing and I have done. My apparatus of reeds, fixed against the + walls of the garden, supplied me with a remarkable nest of the Horned + Osmia. The nest is established in a bit of reed 11 millimetres wide + inside. (.429 inch—Translator's Note.) It comprises thirteen cells + and occupies only half the cylinder, although the orifice is plugged with + the usual stopper. The laying therefore seems here to be complete. + </p> + <p> + Well, this laying is arranged in a most singular fashion. There is first, + at a suitable distance from the bottom or the node of the reed, a + transversal partition, perpendicular to the axis of the tube. This marks + off a cell of unusual size, in which a female is lodged. After that, in + view of the excessive width of the tunnel, which is too great for a series + in single file, the Osmia appears to alter her mind. She therefore builds + a partition perpendicular to the transversal partition which she has just + constructed and thus divides the second storey into two rooms, a larger + room, in which she lodges a female, and a smaller, in which she lodges a + male. She next builds a second transversal partition and a second + longitudinal partition perpendicular to it. These once more give two + unequal chambers, stocked likewise, the large one with a female, the + smaller one with a male. + </p> + <p> + From this third storey onwards, the Osmia abandons geometrical accuracy; + the architect seems to be a little out in her reckoning. The transversal + partitions become more and more slanting and the work grows irregular, but + always with a sprinkling of large chambers for the females and small + chambers for the males. Three females and two males are housed in this + way, the sexes alternating. + </p> + <p> + By the time that the base of the eleventh cell is reached, the transversal + partition is once more almost perpendicular to the axis. Here what + happened at the bottom is repeated. There is no longitudinal partition; + and the spacious cell, covering the whole diameter of the cylinder, + receives a female. The edifice ends with two transversal partitions and + one longitudinal partition, which mark out, on the same level, chambers + twelve and thirteen, both of which contain males. + </p> + <p> + There is nothing more curious than this mixing of the two sexes, when we + know with what precision the Osmia separates them in a linear series, + where the narrow width of the cylinder demands that the cells shall be set + singly, one above the other. Here, the Bee is making use of a tube whose + diameter is not suited to her work; she is constructing a complex and + difficult edifice, which perhaps would not possess the necessary solidity + if the ceilings were too broad. The Osmia therefore supports these + ceilings with longitudinal partitions; and the unequal chambers resulting + from the introduction of these partitions receive females at one time and + males at another, according to their capacity. + </p> + <p> + <a name="link2HCH0005" id="link2HCH0005"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 5. PERMUTATIONS OF SEX. + </h2> + <p> + The sex of the egg is optional. The choice rests with the mother, who is + guided by considerations of space and, according to the accommodation at + her disposal, which is frequently fortuitous and incapable of + modification, places a female in this cell and a male in that, so that + both may have a dwelling of a size suited to their unequal development. + This is the unimpeachable evidence of the numerous and varied facts which + I have set forth. People unfamiliar with insect anatomy—the public + for whom I write—would probably give the following explanation of + this marvellous prerogative of the Bee: the mother has at her disposal a + certain number of eggs, some of which are irrevocably female and the + others irrevocably male: she is able to pick out of either group the one + which she wants at the actual moment; and her choice is decided by the + holding capacity of the cell that has to be stocked. Everything would then + be limited to a judicious selection from the heap of eggs. + </p> + <p> + Should this idea occur to him, the reader must hasten to reject it. + Nothing could be more false, as the merest reference to anatomy will show. + The female reproductive apparatus of the Hymenoptera consists generally of + six ovarian tubes, something like glove-fingers, divided into bunches of + three and ending in a common canal, the oviduct, which carries the eggs + outside. Each of these glove-fingers is fairly wide at the base, but + tapers sharply towards the tip, which is closed. It contains, arranged in + a row, one after the other, like beads on a string, a certain number of + eggs, five or six for instance, of which the lower ones are more or less + developed, the middle ones half-way towards maturity, and the upper ones + very rudimentary. Every stage of evolution is here represented, + distributed regularly from bottom to top, from the verge of maturity to + the vague outlines of the embryo. The sheath clasps its string of ovules + so closely that any inversion of the order is impossible. Besides, an + inversion would result in a gross absurdity: the replacing of a riper egg + by another in an earlier stage of development. + </p> + <p> + Therefore, in each ovarian tube, in each glove-finger, the emergence of + the eggs occurs according to the order governing their arrangement in the + common sheath; and any other sequence is absolutely impossible. Moreover, + at the nesting period, the six ovarian sheaths, one by one and each in its + turn, have at their base an egg which in a very short time swells + enormously. Some hours or even a day before the laying, that egg by itself + represents or even exceeds in bulk the whole of the ovigenous apparatus. + This is the egg which is on the point of being laid. It is about to + descend into the oviduct, in its proper order, at its proper time; and the + mother has no power to make another take its place. It is this egg, + necessarily this egg and no other, that will presently be laid upon the + provisions, whether these be a mess of honey or a live prey; it alone is + ripe, it alone is at the entrance to the oviduct; none of the others, + since they are farther back in the row and not at the right stage of + development, can be substituted at this crisis. Its birth is inevitable. + </p> + <p> + What will it yield, a male or a female? No lodging has been prepared, no + food collected for it; and yet both food and lodging have to be in keeping + with the sex that will proceed from it. And here is a much more puzzling + condition: the sex of that egg, whose advent is predestined, has to + correspond with the space which the mother happens to have found for a + cell. There is therefore no room for hesitation, strange though the + statement may appear: the egg, as it descends from its ovarian tube, has + no determined sex. It is perhaps during the few hours of its rapid + development at the base of its ovarian sheath, it is perhaps on its + passage through the oviduct that it receives, at the mother's pleasure, + the final impress that will produce, to match the cradle which it has to + fill, either a female or a male. + </p> + <p> + Thereupon the following question presents itself. Let us admit that, when + the normal conditions remain, a laying would have yielded m females and n + males. Then, if my conclusions are correct, it must be in the mother's + power, when the conditions are different, to take from the m group and + increase the n group to the same extent; it must be possible for her + laying to be represented as m-1, m-2, m-3, etc. females and by n+1, n+2, + n+3, etc. males, the sum of m+n remaining constant, but one of the sexes + being partly permuted into the other. The ultimate conclusion even cannot + be disregarded: we must admit a set of eggs represented by m-m, or zero, + females and of n+m males, one of the sexes being completely replaced by + the other. Conversely, it must be possible for the feminine series to be + augmented from the masculine series to the extent of absorbing it + entirely. It was to solve this question and some others connected with it + that I undertook, for the second time, to rear the Three-horned Osmia in + my study. + </p> + <p> + The problem on this occasion is a more delicate one; but I am also + better-equipped. My apparatus consists of two small, closed packing-cases, + with the front side of each pierced with forty holes, in which I can + insert my glass tubes and keep them in a horizontal position. I thus + obtain for the Bees the darkness and mystery which suit their work and for + myself the power of withdrawing from my hive, at any time, any tube that I + wish, with the Osmia inside, so as to carry it to the light and follow, if + need be with the aid of the lens, the operations of the busy worker. My + investigations, however frequent and minute, in no way hinder the + peaceable Bee, who remains absorbed in her maternal duties. + </p> + <p> + I mark a plentiful number of my guests with a variety of dots on the + thorax, which enables me to follow any one Osmia from the beginning to the + end of her laying. The tubes and their respective holes are numbered; a + list, always lying open on my desk, enables me to note from day to day, + sometimes from hour to hour, what happens in each tube and particularly + the actions of the Osmiae whose backs bear distinguishing marks. As soon + as one tube is filled, I replace it by another. Moreover, I have scattered + in front of either hive a few handfuls of empty Snail-shells, specially + chosen for the object which I have in view. Reasons which I will explain + later led me to prefer the shells of Helix caespitum. Each of the shells, + as and when stocked, received the date of the laying and the alphabetical + sign corresponding with the Osmia to whom it belonged. In this way, I + spent five or six weeks in continual observation. To succeed in an + enquiry, the first and foremost condition is patience. This condition I + fulfilled; and it was rewarded with the success which I was justified in + expecting. + </p> + <p> + The tubes employed are of two kinds. The first, which are cylindrical and + of the same width throughout, will be of use for confirming the facts + observed in the first year of my experiments in indoor rearing. The + others, the majority, consist of two cylinders which are of very different + diameters, set end to end. The front cylinder, the one which projects a + little way outside the hive and forms the entrance-hole, varies in width + between 8 and 12 millimetres. (Between.312 to .468 inch.—Translator's + Note.) The second, the back one, contained entirely within my + packing-case, is closed at its far end and is 5 to 6 millimetres (.195 + to.234 inch.—Translator's Note.) in diameter. Each of the two parts + of the double-galleried tunnel, one narrow and one wide, measures at most + a decimetre (3.9 inches.—Translator's Note.) in length. I thought it + advisable to have these short tubes, as the Osmia is thus compelled to + select different lodgings, each of them being insufficient in itself to + accommodate the total laying. In this way I shall obtain a greater variety + in the distribution of the sexes. Lastly, at the mouth of each tube, which + projects slightly outside the case, there is a little paper tongue, + forming a sort of perch on which the Osmia alights on her arrival and + giving easy access to the house. With these facilities, the swarm + colonized fifty-two double-galleried tubes, thirty-seven cylindrical + tubes, seventy-eight Snail-shells and a few old nests of the Mason-bee of + the Shrubs. From this rich mine of material I will take what I want to + prove my case. + </p> + <p> + Every series, even when incomplete, begins with females and ends with + males. To this rule I have not yet found an exception, at least in + galleries of normal diameter. In each new abode, the mother busies herself + first of all with the more important sex. Bearing this point in mind, + would it be possible for me, by manoeuvring, to obtain an inversion of + this order and make the laying begin with males? I think so, from the + results already ascertained and the irresistible conclusions to be drawn + from them. The double-galleried tubes are installed in order to put my + conjectures to the proof. + </p> + <p> + The back gallery, 5 or 6 millimetres (.195 to.234 inch.—Translator's + Note.) wide, is too narrow to serve as a lodging for normally developed + females. If, therefore, the Osmia, who is very economical of her space, + wishes to occupy them, she will be obliged to establish males there. And + her laying must necessarily begin here, because this corner is the + rear-most part of the tube. The foremost gallery is wide, with an + entrance-door on the front of the hive. Here, finding the conditions to + which she is accustomed, the mother will go on with her laying in the + order which she prefers. + </p> + <p> + Let us now see what has happened. Of the fifty-two double galleried tubes, + about a third did not have their narrow passage colonized. The Osmia + closed its aperture communicating with the large passage; and the latter + alone received the eggs. This waste of space was inevitable. The female + Osmiae, though nearly always larger than the males, present marked + differences among one another: some are bigger, some are smaller. I had to + adjust the width of the narrow galleries to Bees of average dimensions. It + may happen therefore that a gallery is too small to admit the large-sized + mothers to whom chance allots it. When the Osmia is unable to enter the + tube, obviously she will not colonize it. She then closes the entrance to + this space which she cannot use and does her laying beyond it, in the wide + tube. Had I tried to avoid these useless apparatus by choosing tubes of + larger calibre, I should have encountered another drawback: the + medium-sized mothers, finding themselves almost comfortable, would have + decided to lodge females there. I had to be prepared for it: as each + mother selected her house at will and as I was unable to interfere in her + choice, a narrow tube would be colonized or not, according as the Osmia + who owned it was or was not able to make her way inside. + </p> + <p> + There remain some forty pairs of tubes with both galleries colonized. In + these there are two things to take into consideration. The narrow rear + tubes of 5 or 5 1/2 millimetres (.195 to.214 inch.—Translator's + Note.)—and these are the most numerous—contain males and males + only, but in short series, between one and five. The mother is here so + much hampered in her work that they are rarely occupied from end to end; + the Osmia seems in a hurry to leave them and to go and colonize the front + tube, whose ample space will leave her the liberty of movement necessary + for her operations. The other rear tubes, the minority, whose diameter is + about 6 millimetres (.234 inch.—Translator's Note.), contain + sometimes only females and sometimes females at the back and males towards + the opening. One can see that a tube a trifle wider and a mother slightly + smaller would account for this difference in the results. Nevertheless, as + the necessary space for a female is barely provided in this case, we see + that the mother avoids as far as she can a two-sex arrangement beginning + with males and that she adopts it only in the last extremity. Finally, + whatever the contents of the small tube may be, those of the large one, + following upon it, never vary and consist of females at the back and males + in front. + </p> + <p> + Though incomplete, because of circumstances very difficult to control, the + result of the experiment is none the less very striking. Twenty-five + apparatus contain only males in their narrow gallery, in numbers varying + from a minimum of one to a maximum of five. After these comes the colony + of the large gallery, beginning with females and ending with males. And + the layings in these apparatus do not always belong to late summer or even + to the intermediate period: a few small tubes contain the earliest eggs of + the Osmiae. A couple of Osmiae, more forward than the others, set to work + on the 23rd of April. Both of them started their laying by placing males + in the narrow tubes. The meagre supply of provisions was enough in itself + to show the sex, which proved later to be in accordance with my + anticipations. We see then that, by my artifices, the whole swarm starts + with the converse of the normal order. This inversion is continued, at no + matter what period, from the beginning to the end of the operations. The + series which, according to rule, would begin with females now begins with + males. Once the larger gallery is reached, the laying is pursued in the + usual order. + </p> + <p> + We have advanced one step and that no small one: we have seen that the + Osmia, when circumstances require it, is capable of reversing the sequence + of the sexes. Would it be possible, provided that the tube were long + enough, to obtain a complete inversion, in which the entire series of the + males should occupy the narrow gallery at the back and the entire series + of the females the roomy gallery in front? I think not; and I will tell + you why. + </p> + <p> + Long and narrow cylinders are by no means to the Osmia's taste, not + because of their narrowness but because of their length. Remember that for + each load of honey brought the worker is obliged to move backwards twice. + She enters, head first, to begin by disgorging the honey-syrup from her + crop. Unable to turn in a passage which she blocks entirely, she goes out + backwards, crawling rather than walking, a laborious performance on the + polished surface of the glass and a performance which, with any other + surface, would still be very awkward, as the wings are bound to rub + against the wall with their free end and are liable to get rumpled or + bent. She goes out backwards, reaches the outside, turns round and goes in + again, but this time the opposite way, so as to brush off the load of + pollen from her abdomen on to the heap. If the gallery is at all long, + this crawling backwards becomes troublesome after a time; and the Osmia + soon abandons a passage that is too small to allow of free movement. I + have said that the narrow tubes of my apparatus are, for the most part, + only very incompletely colonized. The Bee, after lodging a small number of + males in them, hastens to leave them. In the wide front gallery, she can + stay where she is and still be able to turn round easily for her different + manipulations; she will avoid those two long journeys backwards, which are + so exhausting and so bad for her wings. + </p> + <p> + Another reason no doubt prompts her not to make too great a use of the + narrow passage, in which she would establish males, followed by females in + the part where the gallery widens. The males have to leave their cells a + couple of weeks or more before the females. If they occupy the back of the + house, they will die prisoners or else they will overturn everything on + their way out. This risk is avoided by the order which the Osmia adopts. + </p> + <p> + In my tubes with their unusual arrangement, the mother might well find the + dilemma perplexing: there is the narrowness of the space at her disposal + and there is the emergence later on. In the narrow tubes, the width is + insufficient for the females; on the other hand, if she lodges males + there, they are liable to perish, since they will be prevented from + issuing at the proper moment. This would perhaps explain the mother's + hesitation and her obstinacy in settling females in some of my apparatus + which looked as if they could suit none but males. + </p> + <p> + A suspicion occurs to me, a suspicion aroused by my attentive examination + of the narrow tubes. All, whatever the number of their inmates, are + carefully plugged at the opening, just as separate tubes would be. It + might therefore be the case that the narrow gallery at the back was looked + upon by the Osmia not as the prolongation of the large front gallery, but + as an independent tube. The facility with which the worker turns as soon + as she reaches the wide tube, her liberty of action, which is now as great + as in a doorway communicating with the outer air, might well be misleading + and cause the Osmia to treat the narrow passage at the back as though the + wide passage in front did not exist. This would account for the placing of + the female in the large tube above the males in the small tube, an + arrangement contrary to her custom. + </p> + <p> + I will not undertake to decide whether the mother really appreciates the + danger of my snares, or whether she makes a mistake in considering only + the space at her disposal and beginning with males. At any rate, I + perceive in her a tendency to deviate as little as possible from the order + which safeguards the emergence of the two sexes. This tendency is + demonstrated by her repugnance to colonizing my narrow tubes with long + series of males. However, so far as we are concerned, it does not matter + much what passes at such times in the Osmia's little brain. Enough for us + to know that she dislikes narrow and long tubes, not because they are + narrow, but because they are at the same time long. + </p> + <p> + And, in fact, she does very well with a short tube of the same diameter. + Such are the cells in the old nests of the Mason-bee of the Shrubs and the + empty shells of the Garden Snail. With the short tube, the two + disadvantages of the long tube are avoided. She has very little of that + crawling backwards to do when she has a Snail-shell for the home of her + eggs and scarcely any when the home is the cell of the Mason-bee. + Moreover, as the stack of cocoons numbers two or three at most, the + deliverance will be exempt from the difficulties attached to a long + series. To persuade the Osmia to nidify in a single tube long enough to + receive the whole of her laying and at the same time narrow enough to + leave her only just the possibility of admittance appears to me a project + without the slightest chance of success: the Bee would stubbornly refuse + such a dwelling or would content herself with entrusting only a very small + portion of her eggs to it. On the other hand, with narrow but short + cavities, success, without being easy, seems to me at least quite + possible. Guided by these considerations, I embarked upon the most arduous + part of my problem: to obtain the complete or almost complete permutation + of one sex with the other; to produce a laying consisting only of males by + offering the mother a series of lodgings suited only to males. + </p> + <p> + Let us in the first place consult the old nests of the Mason-bee of the + Shrubs. I have said that these mortar spheroids, pierced all over with + little cylindrical cavities, are adopted pretty eagerly by the + Three-horned Osmia, who colonizes them before my eyes with females in the + deep cells and males in the shallow cells. That is how things go when the + old nest remains in its natural state. With a grater, however, I scrape + the outside of another nest so as to reduce the depth of the cavities to + some ten millimetres. (About two-fifths of an inch.—Translator's + Note.) This leaves in each cell just room for one cocoon, surmounted by + the closing stopper. Of the fourteen cavities in the nests, I leave two + intact, measuring fifteen millimetres in depth. (.585 inch.—Translator's + Note.) Nothing could be more striking than the result of this experiment, + made in the first year of my home rearing. The twelve cavities whose depth + had been reduced all received males; the two cavities left untouched + received females. + </p> + <p> + A year passes and I repeat the experiment with a nest of fifteen cells; + but this time all the cells are reduced to the minimum depth with the + grater. Well, the fifteen cells, from first to last, are occupied by + males. It must be quite understood that, in each case, all the offspring + belonged to one mother, marked with her distinguishing spot and kept in + sight as long as her laying lasted. He would indeed be difficult to please + who refused to bow before the results of these two experiments. If, + however, he is not yet convinced, here is something to remove his last + doubts. + </p> + <p> + The Three-horned Osmia often settles her family in old shells, especially + those of the Common Snail (Helix aspersa), who is so common under the + stone-heaps and in the crevices of the little unmortared walls that + support our terraces. In this species, the spiral is wide open, so that + the Osmia, penetrating as far down as the helical passage permits, finds, + immediately above the point which is too narrow to pass, the space + necessary for the cell of a female. This cell is succeeded by others, + wider still, always for females, arranged in a line in the same way as in + a straight tube. In the last whorl of the spiral, the diameter would be + too great for a single row. Then longitudinal partitions are added to the + transverse partitions, the whole resulting in cells of unequal dimensions + in which males predominate, mixed with a few females in the lower storeys. + The sequence of the sexes is therefore what it would be in a straight tube + and especially in a tube with a wide bore, where the partitioning is + complicated by subdivisions on the same level. A single Snail-shell + contains room for six or eight cells. A large, rough earthen stopper + finishes the nest at the entrance to the shell. + </p> + <p> + As a dwelling of this sort could show us nothing new, I chose for my swarm + the Garden Snail (Helix caespitum), whose shell, shaped like a small, + swollen Ammonite, widens by slow degrees, the diameter of the usable + portion, right up to the mouth, being hardly greater than that required by + a male Osmia-cocoon. Moreover, the widest part, in which a female might + find room, has to receive a thick stopping-plug, below which there will + often be a free space. Under all these conditions, the house will hardly + suit any but males arranged one after the other. + </p> + <p> + The collection of shells placed at the foot of each hive includes + specimens of different sizes. The smallest are 18 millimetres (.7 inch.—Translator's + Note.) in diameter and the largest 24 millimetres (.936 inch.—Translator's + Note.) There is room for two cocoons, or three at most, according to their + dimensions. + </p> + <p> + Now these shells were used by my visitors without any hesitation, perhaps + even with more eagerness than the glass tubes, whose slippery sides might + easily be a little annoying to the Bee. Some of them were occupied on the + first few days of the laying; and the Osmia who had started with a home of + this sort would pass next to a second Snail-shell, in the immediate + neighbourhood of the first, to a third, a fourth and others still, always + close to one another, until her ovaries were emptied. The whole family of + one mother would thus be lodged in Snail-shells which were duly marked + with the date of the laying and a description of the worker. The faithful + adherents of the Snail-shell were in the minority. The greater number left + the tubes to come to the shells and then went back from the shells to the + tubes. All, after filling the spiral staircase with two or three cells, + closed the house with a thick earthen stopper on a level with the opening. + It was a long and troublesome task, in which the Osmia displayed all her + patience as a mother and all her talents as a plasterer. There were even + some who, scrupulous to excess, carefully cemented the umbilicus, a hole + which seemed to inspire them with distrust as being able to give access to + the interior of the dwelling. It was a dangerous-looking cavity, which for + the greater safety of the family it was prudent to block up. + </p> + <p> + When the pupae are sufficiently matured, I proceed to examine these + elegant abodes. The contents fill me with joy: they fulfil my + anticipations to the letter. The great, the very great majority of the + cocoons turn out to be males; here and there, in the bigger cells, a few + rare females appear. The smallness of the space has almost done away with + the sixty-eight Snail-shells colonized. But, of this total number, I must + use only those series which received an entire laying and were occupied by + the same Osmia from the beginning to the end of the egg-season. Here are a + few examples, taken from among the most conclusive. + </p> + <p> + From the 6th of May, when she started operations, to the 25th of May, the + date at which her laying ceased, the Osmia occupied seven Snail-shells in + succession. Her family consists of fourteen cocoons, a number very near + the average; and, of these fourteen cocoons, twelve belong to males and + only two to females. These occupy the seventh and thirteenth places in + chronological order. + </p> + <p> + Another, between the 9th and 27th of May, stocked six Snail-shells with a + family of thirteen, including ten males and three females. The places + occupied by the latter in the series were numbers 3, 4 and 5. + </p> + <p> + A third, between the 2nd and 29th of May, colonized eleven Snail-shells, a + prodigious task. This industrious one was also exceedingly prolific. She + supplied me with a family of twenty-six, the largest which I have ever + obtained from one Osmia. Well, this abnormal progeny consisted of + twenty-five males and one female, one alone, occupying place 17. + </p> + <p> + There is no need to go on, after this magnificent example, especially as + the other series would all, without exception, give us the same result. + Two facts are immediately obvious. The Osmia is able to reverse the order + of her laying and to start with a more or less long series of males before + producing any females. In the first case, the first female appears as + number 7; in the third, as number 17. There is something better still; and + this is the proposition which I was particularly anxious to prove: the + female sex can be permuted with the male sex and can be permuted to the + point of disappearing altogether. We see this especially in the third + case, where the presence of a solitary female in a family of twenty-six is + due to the somewhat larger diameter of the corresponding Snail-shell and + also, no doubt, to some mistake on the mother's part, for the female + cocoon, in a series of two, occupies the upper storey, the one next to the + orifice, an arrangement which the Osmia appears to me to dislike. + </p> + <p> + This result throws so much light on one of the darkest corners of biology + that I must attempt to corroborate it by means of even more conclusive + experiments. I propose next year to give the Osmiae nothing but + Snail-shells for a lodging, picked out one by one, and rigorously to + deprive the swarm of any other retreat in which the laying could be + effected. Under these conditions, I ought to obtain nothing but males, or + nearly, for the whole swarm. + </p> + <p> + There would still remain the inverse permutation: to obtain only females + and no males, or very few. The first permutation makes the second seem + very probable, although I cannot as yet conceive a means of realizing it. + The only condition which I can regulate is the dimensions of the home. + When the rooms are small, the males abound and the females tend to + disappear. With generous quarters, the converse would not take place. I + should obtain females and afterwards an equal number of males, confined in + small cells which, in case of need, would be bounded by numerous + partitions. The factor of space does not enter into the question here. + What artifice can we then employ to provoke this second permutation? So + far, I can think of nothing that is worth attempting. + </p> + <p> + It is time to conclude. Leading a retired life, in the solitude of a + village, having quite enough to do with patiently and obscurely ploughing + my humble furrow, I know little about modern scientific views. In my young + days I had a passionate longing for books and found it difficult to + procure them; to-day, when I could almost have them if I wanted, I am + ceasing to wish for them. It is what usually happens as life goes on. I do + not therefore know what may have been done in the direction whither this + study of the sexes has led us. If I am stating propositions that are + really new or at least more comprehensive than the propositions already + known, my words will perhaps sound heretical. No matter: as a simple + translator of facts, I do not hesitate to make my statement, being fully + persuaded that time will turn my heresy into orthodoxy. I will therefore + recapitulate my conclusions. + </p> + <p> + Bees lay their eggs in series of first females and then males, when the + two sexes are of different sizes and demand an unequal quantity of + nourishment. When the two sexes are alike in size, the same sequence may + occur, but less regularly. + </p> + <p> + This dual arrangement disappears when the place chosen for the nest is not + large enough to contain the entire laying. We then see broken layings, + beginning with females and ending with males. + </p> + <p> + The egg, as it issues from the ovary, has not yet a fixed sex. The final + impress that produces the sex is given at the moment of laying or a little + before. + </p> + <p> + So as to be able to give each larva the amount of space and food that + suits it according as it is male or female, the mother can choose the sex + of the egg which she is about to lay. To meet the conditions of the + building, which is often the work of another or else a natural retreat + that admits of little or no alteration, she lays either a male egg or a + female egg as she pleases. The distribution of the sexes depends upon + herself. Should circumstances require it, the order of the laying can be + reversed and begin with males; lastly, the entire laying can contain only + one sex. + </p> + <p> + The same privilege is possessed by the predatory Hymenoptera, the Wasps, + at least by those in whom the two sexes are of a different size and + consequently require an amount of nourishment that is larger in the one + case than in the other. The mother must know the sex of the egg which she + is going to lay; she must be able to choose the sex of that egg so that + each larva may obtain its proper portion of food. + </p> + <p> + Generally speaking, when the sexes are of different sizes, every insect + that collects food and prepares or selects a dwelling for its offspring + must be able to choose the sex of the egg in order to satisfy without + mistake the conditions imposed upon it. + </p> + <p> + The question remains how this optional assessment of the sexes is + effected. I know absolutely nothing about it. If I should ever learn + anything about this delicate point, I shall owe it to some happy chance + for which I must wait, or rather watch, patiently. Towards the end of my + investigations, I heard of a German theory which relates to the Hive-bee + and comes from Dzierzon, the apiarist. (Johann Dzierzon, author of + "Theorie und Praxis des neuen Bienenfreundes."—Translator's Note.) + If I understand it aright, according to the very incomplete documents + which I have before me, the egg, as it issues from the ovary, is said + already to possess a sex, which is always the same; it is originally male; + and it becomes female by fertilization. The males are supposed to proceed + from non-fertilized eggs, the females from fertilized eggs. The Queen-bee + would thus lay female eggs or male eggs according as she fertilized them + or not while they were passing into her oviduct. + </p> + <p> + Coming from Germany, this theory cannot but inspire me with profound + distrust. As it has been given acceptance, with rash precipitancy, in + standard works, I will overcome my reluctance to devoting my attention to + Teutonic ideas and will submit it not to the test of argument, which can + always be met by an opposite argument, but to the unanswerable test of + facts. + </p> + <p> + For this optional fertilization, determining the sex, the mother's + organism requires a seminal reservoir which distils its drop of sperm upon + the egg contained in the oviduct and thus gives it a feminine character, + or else leaves it its original character, the male character, by refusing + it that baptism. This reservoir exists in the Hive-bee. Do we find a + similar organ in the other Hymenoptera, whether honey-gatherers or + hunters? The anatomical treatises are either silent on this point or, + without further enquiry, apply to the order as a whole the data provided + by the Hive-bee, however much she differs from the mass of Hymenoptera + owing to her social habits, her sterile workers and especially her + tremendous fertility, extending over so long a period. + </p> + <p> + I at first doubted the universal presence of this spermatic receptacle, + having failed to find it under my scalpel in my former investigations into + the anatomy of the Sphex-wasps and some other game-hunters. But this organ + is so delicate and so small that it very easily escapes the eye, + especially when our attention is not specially directed in search of it; + and, even when we are looking for it and it only, we do not always succeed + in discovering it. We have to find a globule attaining in many cases + hardly as much as a millimetre (About one-fiftieth of an inch.—Translator's + Note.) in diameter, a globule headed amidst a tangle of air-ducts and + fatty patches, of which it shares the colour, a dull white. Then again, + the merest slip of the forceps is enough to destroy it. My first + investigations, therefore, which concerned the reproductive apparatus as a + whole, might very well have allowed it to pass unperceived. + </p> + <p> + In order to know the rights of the matter once and for all, as the + anatomical treatises taught me nothing, I once more fixed my microscope on + its stand and rearranged my old dissecting-tank, an ordinary tumbler with + a cork disk covered with black satin. This time, not without a certain + strain on my eyes, which are already growing tired, I succeeded in finding + the said organ in the Bembex-wasps, the Halicti (Cf. Chapters 12 to 14 of + the present volume.—Translator's Note.), the Carpenter-bees, the + Bumble-bees, the Andrenae (A species of Burrowing Bees.—Translator's + Note.) and the Megachiles. (Or Leaf-cutting Bees. Cf. Chapter 8 of the + present volume.—Translator's Note.) I failed in the case of the + Osmiae, the Chalicodomae and the Anthophorae. Is the organ really absent? + Or was there want of skill on my part? I lean towards want of skill and + admit that all the game-hunting and honey-gathering Hymenoptera possess a + seminal receptacle, which can be recognized by its contents, a quantity of + spiral spermatozoids whirling and twisting on the slide of the microscope. + </p> + <p> + This organ once accepted, the German theory becomes applicable to all the + Bees and all the Wasps. When copulating, the female receives the seminal + fluid and holds it stored in her receptacle. From that moment, the two + procreating elements are present in the mother at one and the same time: + the female element, the ovule; and the male element, the spermatozoid. At + the egg-layer's will, the receptacle bestows a tiny drop of its contents + upon the matured ovule, when it reaches the oviduct, and you have a female + egg; or else it withholds its spermatozoids and you have an egg that + remains male, as it was at first. I readily admit it: the theory is very + simple, lucid and seductive. But is it correct? That is another question. + </p> + <p> + One might begin by reproaching it with making a singular exception to one + of the most general rules. Which of us, casting his eyes over the whole + zoological progression, would dare to assert that the egg is originally + male and that it becomes female by fertilization? Do not the two sexes + both call for the assistance of the fertilizing element? If there be one + undoubted truth, it is certainly that. We are, it is true, told very + curious things about the Hive-bee. I will not discuss them: this Bee + stands too far outside the ordinary limits; and then the facts asserted + are far from being accepted by everybody. But the non-social Bees and the + predatory insects have nothing special about their laying. Then why should + they escape the common rule, which requires that every living creature, + male as well as female, should come from a fertilized ovule? In its most + solemn act, that of procreation, life is one and uniform; what it does + here it does there and there and everywhere. What! The sporule of a scrap + of moss requires an antherozoid before it is fit to germinate; and the + ovule of a Scolia, that proud huntress, can dispense with the equivalent + in order to hatch and produce a male? These new-fangled theories seem to + me to have very little value. + </p> + <p> + One might also bring forward the case of the Three-pronged Osmia, who + distributes the two sexes without any order in the hollow of her reed. + What singular whim is the mother obeying when, without decisive motive, + she opens her seminal phial at haphazard to anoint a female egg, or else + keeps it closed, also at haphazard, to allow a male egg to pass + unfertilized? I could imagine impregnation being given or withheld for + periods of some duration; but I cannot understand impregnation and + non-impregnation following upon each other anyhow, in any sort of order, + or rather with no order it all. The mother has just fertilized an egg. Why + should she refuse to fertilize the next, when neither the provisions nor + the lodgings differ in the smallest respect from the previous provisions + and lodgings? These capricious alternations, so unreasonable and so + exceedingly erratic, are scarcely appropriate to an act of such + importance. + </p> + <p> + But I promised not to argue and I find myself arguing. My reasoning is too + fine for dull wits. I will pass on and come to the brutal fact, the real + sledge-hammer blow. + </p> + <p> + Towards the end of the Bee's operations, in the first week of June, the + last acts of the Three-horned Osmia become so exceptionally interesting + that I made her the object of redoubled observation. The swarm at this + time is greatly reduced in numbers. I have still some thirty laggards, who + continue very busy, though their work is in vain. I see some very + conscientiously stopping up the entrance to a tube or a Snail-shell in + which they have laid nothing at all. Others are closing the home after + only building a few partitions, or even mere attempts at partitions. Some + are placing at the back of a new gallery a pinch of pollen which will + benefit nobody and then shutting up the house with an earthen stopper as + thick, as carefully made as though the safety of a family depended on it. + Born a worker, the Osmia must die working. When her ovaries are exhausted, + she spends the remainder of her strength on useless works: partitions, + plugs, pollen-heaps, all destined to be left unemployed. The little animal + machine cannot bring itself to be inactive even when there is nothing more + to be done. It goes on working so that its last vibrations of energy may + be used up in fruitless labour. I commend these aberrations to the staunch + supporters of reasoning-powers in the animal. + </p> + <p> + Before coming to these useless tasks, my laggards have laid their last + eggs, of which I know the exact cells, the exact dates. These eggs, as far + as the microscopes can tell, differ in no respect from the others, the + older ones. They have the same dimensions, the same shape, the same + glossiness, the same look of freshness. Nor are their provisions in any + way peculiar, being very well suited to the males, who conclude the + laying. And yet these last eggs do not hatch: they wrinkle, fade and + wither on the pile of food. In one case, I count three or four sterile + eggs among the last lot laid; in another, I find two or only one. + Elsewhere in the swarm, fertile eggs have been laid right up to the end. + </p> + <p> + Those sterile eggs, stricken with death at the moment of their birth, are + too numerous to be ignored. Why do they not hatch like the other eggs, + which outwardly they resemble in every respect? They have received the + same attention from the mother and the same portion of food. The searching + microscope shows me nothing in them to explain the fatal ending. + </p> + <p> + To the unprejudiced mind, the answer is obvious. Those eggs do not hatch + because they have not been fertilized. Any animal or vegetable egg that + had not received the life-giving impregnation would perish in the same + way. No other answer is possible. It is no use talking of the distant + period of the laying: eggs of the same period laid by other mothers, eggs + of the same date and likewise the final ones of a laying, are perfectly + fertile. Once more, they do not hatch because they were not fertilized. + </p> + <p> + And why were they not fertilized? Because the seminal receptacle, so tiny, + so difficult to see that it sometimes escaped me despite all my scrutiny, + had exhausted its contents. The mothers in whom this receptacle retained a + remnant of sperm to the end had their last eggs as fertile as the first; + the others, whose seminal reservoir was exhausted too soon, had their + last-born stricken with death. All this seems to me as clear as daylight. + </p> + <p> + If the unfertilized eggs perish without hatching, those which hatch and + produce males are therefore fertilized; and the German theory falls to the + ground. + </p> + <p> + Then what explanation shall I give of the wonderful facts which I have set + forth? Why, none, absolutely none. I do not explain facts, I relate them. + Growing daily more sceptical of the interpretations suggested to me and + more hesitating as to those which I may have to suggest myself, the more I + observe and experiment, the more clearly I see rising out of the black + mists of possibility an enormous note of interrogation. + </p> + <p> + Dear insects, my study of you has sustained me and continues to sustain me + in my heaviest trials. I must take leave of you for to-day. The ranks are + thinning around me and the long hopes have fled. Shall I be able to speak + to you again? (This is the closing paragraph of Volume 3 of the "Souvenirs + entomologiques," of which the author has lived to publish seven more + volumes, containing over 2,500 pages and nearly 850,000 words.—Translator's + Note.) + </p> + <p> + <a name="link2HCH0006" id="link2HCH0006"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 6. INSTINCT AND DISCERNMENT. + </h2> + <p> + The Pelopaeus (A Mason-wasp forming the subject of essays which have not + yet been published in English.—Translator's Note.) gives us a very + poor idea of her intellect when she plasters up the spot in the wall where + the nest which I have removed used to stand, when she persists in cramming + her cell with Spiders for the benefit of an egg no longer there and when + she dutifully closes a cell which my forceps has left empty, extracting + alike germ and provisions. The Mason-bees (Cf. "The Mason-bees": chapter + 7.—Translator's Note.), the caterpillar of the Great Peacock Moth + (Cf. "Social Life in the Insect World" by J.H. Fabre, translated by + Bernard Miall: chapter 14.—Translator's Note.) and many others, when + subjected to similar tests, are guilty of the same illogical behaviour: + they continue, in the normal order, their series of industrious actions, + though an accident has now rendered them all useless. Just like millstones + unable to cease revolving though there be no corn left to grind, let them + once be given the compelling power and they will continue to perform their + task despite its futility. Are they then machines? Far be it from me to + think anything so foolish. + </p> + <p> + It is impossible to make definite progress on the shifting sands of + contradictory facts: each step in our interpretation may find us embogged. + And yet these facts speak so loudly that I do not hesitate to translate + their evidence as I understand it. In insect mentality, we have to + distinguish two very different domains. One of these is INSTINCT properly + so called, the unconscious impulse that presides over the most wonderful + part of what the creature achieves. Where experience and imitation are of + absolutely no avail, instinct lays down its inflexible law. It is instinct + and instinct alone that makes the mother build for a family which she will + never see; that counsels the storing of provisions for the unknown + offspring; that directs the sting towards the nerve-centres of the prey + and skilfully paralyses it, so that the game may keep good; that + instigates, in fine, a host of actions wherein shrewd reason and + consummate science would have their part, were the creature acting through + discernment. + </p> + <p> + This faculty is perfect of its kind from the outset, otherwise the insect + would have no posterity. Time adds nothing to it and takes nothing from + it. Such as it was for a definite species, such it is to-day and such it + will remain, perhaps the most settled zoological characteristic of them + all. It is not free nor conscious in its practice, any more than is the + faculty of the stomach for digestion or that of the heart for pulsation. + The phases of its operations are predetermined, necessarily entailed one + by another; they suggest a system of clock-work wherein one wheel set in + motion brings about the movement of the next. This is the mechanical side + of the insect, the fatum, the only thing which is able to explain the + monstrous illogicality of a Pelopaeus when misled by my artifices. Is the + Lamb when it first grips the teat a free and conscious agent, capable of + improvement in its difficult art of taking nourishment? The insect is no + more capable of improvement in its art, more difficult still, of giving + nourishment. + </p> + <p> + But, with its hide-bound science ignorant of itself, pure insect, if it + stood alone, would leave the insect unarmed in the perpetual conflict of + circumstances. No two moments in time are identical; though the background + remain the same, the details change; the unexpected rises on every side. + In this bewildering confusion, a guide is needed to seek, accept, refuse + and select; to show preference for this and indifference to that; to turn + to account, in short, anything useful that occasion may offer. This guide + the insect undoubtedly possesses, to a very manifest degree. It is the + second province of its mentality. Here it is conscious and capable of + improvement by experience. I dare not speak of this rudimentary faculty as + intelligence, which is too exalted a title: I will call it DISCERNMENT. + The insect, in exercising its highest gifts, discerns, differentiates + between one thing and another, within the sphere of its business, of + course; and that is about all. + </p> + <p> + As long as we confound acts of pure instinct and acts of discernment under + the same head, we shall fall back into those endless discussions which + embitter controversy without bringing us one step nearer to the solution + of the problem. Is the insect conscious of what it does? Yes and no. No, + if its action is in the province of instinct; yes, if the action is in + that of discernment. Are the habits of an insect capable of modification? + No, decidedly not, if the habit in question belongs to the province of + instinct; yes, if it belongs to that of discernment. Let us state this + fundamental distinction more precisely by the aid of a few examples. + </p> + <p> + The Pelopaeus builds her cells with earth already softened, with mud. Here + we have instinct, the unalterable characteristic of the worker. She has + always built in this way and always will. The passing ages will never + teach her, neither the struggle for life nor the law of selection will + ever induce her to imitate the Mason-bee and collect dry dust for her + mortar. This mud nest needs a shelter against the rain. The hiding-place + under a stone suffices at first. But should she find something better, the + potter takes possession of that something better and instals herself in + the home of man. (The Pelopaeus builds in the fire-places of houses.—Translator's + Note.) There we have discernment, the source of some sort of capacity for + improvement. + </p> + <p> + The Pelopaeus supplies her larvae with provisions in the form of Spiders. + There you have instinct. The climate, the longitude or latitude, the + changing seasons, the abundance or scarcity of game introduce no + modification into this diet, though the larva shows itself satisfied with + other fare provided by myself. Its forebears were brought up on Spiders; + their descendants consumed similar food; and their posterity again will + know no other. Not a single circumstance, however favourable, will ever + persuade the Pelopaeus that young Crickets, for instance, are as good as + Spiders and that her family would accept them gladly. Instinct binds her + down to the national diet. + </p> + <p> + But, should the Epeira (The Weaving or Garden Spider. Cf. "The Life of the + Spider" by J. Henri Fabre translated by Alexander Teixeira de Mattos; + chapters 9 to 14 and appendix.—Translator's Note.), the favourite + prey, be lacking, must the Pelopaeus therefore give up foraging? She will + stock her warehouses all the same, because any Spider suits her. There you + have discernment, whose elasticity makes up, in certain circumstances, for + the too-great rigidity of instinct. Amid the innumerable variety of game, + the huntress is able to discern between what is Spider and what is not; + and, in this way, she is always prepared to supply her family, without + quitting the domain of her instinct. + </p> + <p> + The Hairy Ammophila gives her larva a single caterpillar, a large one, + paralysed by as many pricks of her sting as it has nervous centres in its + thorax and abdomen. Her surgical skill in subduing the monster is instinct + displayed in a form which makes short work of any inclination to see in it + an acquired habit. In an art that can leave no one to practise it in the + future unless that one be perfect at the outset, of what avail are happy + chances, atavistic tendencies, the mellowing hand of time? But the grey + caterpillar, sacrificed one day, may be succeeded on another day by a + green, yellow or striped caterpillar. There you have discernment, which is + quite capable of recognizing the regulation prey under very diverse garbs. + </p> + <p> + The Megachiles build their honey-jars with disks cut out of leaves; + certain Anthidia make felted cotton wallets; others fashion pots out of + resin. There you have instinct. Will any rash mind ever conceive the + singular idea that the Leaf-cutter might very well have started working in + cotton, that the cotton-wool-worker once thought or will one day think of + cutting disks out of the leaves of the lilac- and the rose-tree, that the + resin-kneader began with clay? Who would dare to indulge in any such + theories? Each Bee has her art, her medium, to which she strictly confines + herself. The first has her leaves; the second her wadding; the third her + resin. None of these guilds has ever changed trades with another; and none + ever will. There you have instinct, keeping the workers to their + specialities. There are no innovations in their workshops, no recipes + resulting from experiment, no ingenious devices, no progress from + indifferent to good, from good to excellent. To-day's method is the + facsimile of yesterday's; and to-morrow will know no other. + </p> + <p> + But, though the manufacturing-process is invariable, the raw material is + subject to change. The plant that supplies the cotton differs in species + according to the locality; the bush out of whose leaves the pieces will be + cut is not the same in the various fields of operation; the tree that + provides the resinous putty may be a pine, a cypress, a juniper, a cedar + or a spruce, all very different in appearance. What will guide the insect + in its gleaning? Discernment. + </p> + <p> + These, I think, are sufficient details of the fundamental distinction to + be drawn in the insect's mentality; the distinction, that is, between + instinct and discernment. If people confuse these two provinces, as they + nearly always do, any understanding becomes impossible; the last glimmer + of light disappears behind the clouds of interminable discussions. From an + industrial point of view, let us look upon the insect as a worker + thoroughly versed from birth in a craft whose essential principles never + vary; let us grant that unconscious worker a gleam of intelligence which + will permit it to extricate itself from the inevitable conflict of + attendant circumstances; and I think that we shall have come as near to + the truth as the state of our knowledge will allow for the moment. + </p> + <p> + Having thus assigned a due share both to instinct and the aberrations of + instinct when the course of its different phases is disturbed, let us see + what discernment is able to do in the selection of a site for the nest and + materials for building it; and, leaving the Pelopaeus, upon whom it is + useless to dwell any longer, let us consider other examples, picked from + among those richest in variations. + </p> + <p> + The Mason-bee of the Sheds (Chalicodoma rufitarsis, PEREZ) well deserves + the name which I have felt justified in giving her from her habits: she + settles in numerous colonies in our sheds, on the lower surface of the + tiles, where she builds huge nests which endanger the solidity of the + roof. Nowhere does the insect display a greater zeal for work than in one + of these colossal cities, an estate which is constantly increasing as it + passes down from one generation to another; nowhere does it find a better + workshop for the exercise of its industry. Here it has plenty of room: a + quiet resting-place, sheltered from damp and from excess of heat or cold. + </p> + <p> + But the spacious domain under the tiles is not within the reach of all: + sheds with free access and the proper sunny aspect are pretty rare. These + sites fall only to the favoured of fortune. Where will the others take up + their quarters? More or less everywhere. Without leaving the house in + which I live, I can enumerate stone, wood, glass, metal, paint and mortar + as forming the foundation of the nests. The green-house with its furnace + heat in the summer and its bright light, equalling that outside, is fairly + well-frequented. The Mason-bee hardly ever fails to build there each year, + in squads of a few dozen apiece, now on the glass panes, now on the iron + bars of the framework. Other little swarms settle in the window + embrasures, under the projecting ledge of the front door or in the cranny + between the wall and an open shutter. Others again, being perhaps of a + morose disposition, flee society and prefer to work in solitude, one in + the inside of a lock or of a pipe intended to carry the rain-water from + the leads; another in the mouldings of the doors and windows or in the + crude ornamentation of the stone-work. In short, the house is made use of + all round, provided that the shelter be an out-of-door one; for observe + that the enterprising invader, unlike the Pelopaeus, never penetrates + inside our dwellings. The case of the conservatory is an exception more + apparent than real: the glass building, standing wide open throughout the + summer, is to the Mason-bee but a shed a little lighter than the others. + There is nothing here to arouse the distrust with which anything indoors + or shut up inspires her. To build on the threshold of an outer door, or to + usurp its lock, a hiding-place to her fancy, is all that she allows + herself; to go any farther is an adventure repugnant to her taste. + </p> + <p> + Lastly, in the case of all these dwellings, the Mason-bee is man's free + tenant; her industry makes use of the products of our own industry. Can + she have no other establishments? She has, beyond a doubt; she possesses + some constructed on the ancient plan. On a stone the size of a man's fist, + protected by the shelter of a hedge, sometimes even on a pebble in the + open air, I see her building now groups of cells as large as a walnut, now + domes emulating in size, shape and solidity those of her rival, the + Mason-bee of the Walls. + </p> + <p> + The stone support is the most frequent, though not the only one. I have + found nests, but sparsely inhabited it is true, on the trunks of trees, in + the seams of the rough bark of oaks. Among those whose support was a + living plant, I will mention two that stand out above all the others. The + first was built in the lobe of a torch-thistle as thick as my leg; the + second rested on a stalk of the opuntia, the Indian fig. Had the fierce + armour of these two stout cactuses attracted the attention of the insect, + which looked upon their tufts of spikes as furnishing a system of defence + for its nest? Perhaps so. In any case, the attempt was not imitated; I + never saw another installation of the kind. There is one definite + conclusion to be drawn from my two discoveries. Despite the oddity of + their structure, which is unparalleled among the local flora, the two + American importations did not compel the insect to go through an + apprenticeship of groping and hesitation. The one which found itself in + the presence of those novel growths, and which was perhaps the first of + its race to do so, took possession of their lobes and stalks just as it + would have done of a familiar site. From the start, the fleshy plants from + the New World suited it as well as the trunk of a native tree. + </p> + <p> + The Mason-bee of the Pebbles (Chalicodoma parietina) has none of this + elasticity in the choice of a site. In her case, the smooth stone of the + parched uplands is the almost invariable foundation of her structures. + Elsewhere, under a less clement sky, she prefers the support of a wall, + which protects the nest against the prolonged snows. Lastly, the Mason-bee + of the Shrubs (Chalicodoma rufescens, PEREZ) fixes her ball of clay to a + twig of any ligneous plant, from the thyme, the rock-rose and the heath to + the oak, the elm and the pine. The list of the sites that suit her would + almost form a complete catalogue of the ligneous flora. + </p> + <p> + The variety of places wherein the insect instals itself, so eloquent of + the part played by discernment in their selection, becomes still more + remarkable when it is accompanied by a corresponding variety in the + architecture of the cells. This is more particularly the case with the + Three-horned Osmia, who, as she uses clayey materials very easily affected + by the rain, requires, like the Pelopaeus, a dry shelter for her cells, a + shelter which she finds ready-made and uses just as it is, after a few + touches by way of sweeping and cleansing. The homes which I see her adopt + are especially the shells of Snails that have died under the stone-heaps + and in the low, unmortared walls which support the cultivated earth of the + hills in shelves or terraces. The use of Snail-shells is accompanied by + the no less active use of the old cells of both the Mason-bee of the Sheds + and of certain Anthophorae (A. pilipes, A. parietina and A. personata). + </p> + <p> + We must not forget the reed, which is highly appreciated when—a rare + find—it appears under the requisite conditions. In its natural + state, the plant with the mighty hollow cylinders is of no possible use to + the Osmia, who knows nothing of the art of perforating a woody wall. The + gallery of an internode has to be wide open before the insect can take + possession of it. Also, the clean-cut stump must be horizontal, otherwise + the rain would soften the fragile edifice of clay and soon lay it low; + also, the stump must not be lying on the ground and must be kept at some + distance from the dampness of the soil. We see therefore that, without the + intervention of man, involuntary in the vast majority of cases and + deliberate only on the experimenter's part, the Osmia would hardly ever + find a reed-stump suited to the installation of her family. It is to her a + casual acquisition, a home unknown to her race before men took it into + their heads to cut reeds and make them into hurdles for drying figs in the + sun. + </p> + <p> + How did the work of man's pruning-knife bring about the abandonment of the + natural lodging? How was the spiral staircase of the Snail-shell replaced + by the cylindrical gallery of the reed? Was the change from one kind of + house to another effected by gradual transitions, by attempts made, + abandoned, resumed, becoming more and more definite in their results as + generation succeeded generation? Or did the Osmia, finding the cut reed + that answered her requirements, instal herself there straightway, scorning + her ancient dwelling, the Snail-shell? These questions called for a reply; + and they have received one. Let us describe how things happened. + </p> + <p> + Near Serignan are some great quarries of coarse limestone, characteristic + of the miocene formation of the Rhone valley. These have been worked for + many generations. The ancient public buildings of Orange, notably the + colossal frontage of the theatre whither all the intellectual world once + flocked to hear Sophocles' "Oedipus Tyrannus," derive most of their + material from these quarries. Other evidence confirms what the similarity + of the hewn stone tells us. Among the rubbish that fills up the spaces + between the tiers of seats, they occasionally discover the Marseilles + obol, a bit of silver stamped with the four-spoked wheel, or a few bronze + coins bearing the effigy of Augustus or Tiberius. Scattered also here and + there among the monuments of antiquity are heaps of refuse, accumulations + of broken stones in which various Hymenoptera, including the Three-horned + Osmia in particular, take possession of the dead Snail-shell. + </p> + <p> + The quarries form part of an extensive plateau which is so arid as to be + nearly deserted. In these conditions, the Osmia, at all times faithful to + her birth-place, has little or no need to emigrate from her heap of stones + and leave the shell for another dwelling which she would have to go and + seek at a distance. Since there are heaps of stone there, she probably has + no other dwelling than the Snail-shell. Nothing tells us that the + present-day generations are not descended in the direct line from the + generations contemporary with the quarryman who lost his as or his obol at + this spot. All the circumstances seem to point to it: the Osmia of the + quarries is an inveterate user of Snail-shells; so far as heredity is + concerned, she knows nothing whatever of reeds. Well, we must place her in + the presence of these new lodgings. + </p> + <p> + I collect during the winter about two dozen well-stocked Snail-shells and + instal them in a quiet corner of my study, as I did at the time of my + enquiries into the distribution of the sexes. The little hive with its + front pierced with forty holes has bits of reed fitted to it. At the foot + of the five rows of cylinders I place the inhabited shells and with these + I mix a few small stones, the better to imitate the natural conditions. I + add an assortment of empty Snail-shells, after carefully cleaning the + interior so as to make the Osmia's stay more pleasant. When the time comes + for nest-building, the stay-at-home insect will have, close beside the + house of its birth, a choice of two habitations: the cylinder, a novelty + unknown to its race; and the spiral staircase, the ancient ancestral home. + </p> + <p> + The nests were finished at the end of May and the Osmiae began to answer + my list of questions. Some, the great majority, settled exclusively in the + reeds; the others remained faithful to the Snail-shell or else entrusted + their eggs partly to the spirals and partly to the cylinders. With the + first, who were the pioneers of cylindrical architecture, there was no + hesitation that I could perceive: after exploring the stump of reed for a + time and recognizing it as serviceable, the insect instals itself there + and, an expert from the first touch, without apprenticeship, without + groping, without any tendencies bequeathed by the long practice of its + predecessors, builds its straight row of cells on a very different plan + from that demanded by the spiral cavity of the shell which increases in + size as it goes on. + </p> + <p> + The slow school of the ages, the gradual acquisitions of the past, the + legacies of heredity count for nothing therefore in the Osmia's education. + Without any novitiate on its own part or that of its forebears, the insect + is versed straight away in the calling which it has to pursue; it + possesses, inseparable from its nature, the qualities demanded by its + craft: some which are invariable and belong to the domain of instinct; + others, flexible, belonging to the province of discernment. To divide a + free lodging into chambers by means of mud partitions; to fill those + chambers with a heap of pollen-flour, with a few sups of honey in the + central part where the egg is to lie; in short, to prepare board and + lodging for the unknown, for a family which the mothers have never seen in + the past and will never see in the future: this, in its essential + features, is the function of the Osmia's instinct. Here, everything is + harmoniously, inflexibly, permanently preordained; the insect has but to + follow its blind impulse to attain the goal. But the free lodging offered + by chance varies exceedingly in hygienic conditions, in shape and in + capacity. Instinct, which does not choose, which does not contrive, would, + if it were alone, leave the insect's existence in peril. To help her out + of her predicament, in these complex circumstances, the Osmia possesses + her little stock of discernment, which distinguishes between the dry and + the wet, the solid and the fragile, the sheltered and the exposed; which + recognizes the worth or the worthlessness of a site and knows how to + sprinkle it with cells according to the size and shape of the space at + disposal. Here, slight industrial variations are necessary and inevitable; + and the insect excels in them without any apprenticeship, as the + experiment with the native Osmia of the quarries has just proved. + </p> + <p> + Animal resources have a certain elasticity, within narrow limits. What we + learn from the animals' industry at a given moment is not always the full + measure of their skill. They possess latent powers held in reserve for + certain emergencies. Long generations can succeed one another without + employing them; but, should some circumstance require it, suddenly those + powers burst forth, free of any previous attempts, even as the spark + potentially contained in the flint flashes forth independently of all + preceding gleams. Could one who knew nothing of the Sparrow but her nest + under the eaves suspect the ball-shaped nest at the top of a tree? Would + one who knew nothing of the Osmia save her home in the Snail-shell expect + to see her accept as her dwelling a stump of reed, a paper funnel, a glass + tube? My neighbour the Sparrow, impulsively taking it into her head to + leave the roof for the plane-tree, the Osmia of the quarries, rejecting + her natal cabin, the spiral of the shell, for my cylinder, alike show us + how sudden and spontaneous are the industrial variations of animals. + </p> + <p> + <a name="link2HCH0007" id="link2HCH0007"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 7. ECONOMY OF ENERGY. + </h2> + <p> + What stimulus does the insect obey when it employs the reserve powers that + slumber in its race? Of what use are its industrial variations? The Osmia + will yield us her secret with no great difficulty. Let us examine her work + in a cylindrical habitation. I have described in full detail, in the + foregoing pages, the structure of her nests when the dwelling adopted is a + reed-stump or any other cylinder; and I will content myself here with + recapitulating the essential features of that nest-building. + </p> + <p> + We must first distinguish three classes of reeds according to their + diameter: the small, the medium-sized and the large. I call small those + whose narrow width just allows the Osmia to go about her household duties + without discomfort. She must be able to turn where she stands in order to + brush her abdomen and rub off its load of pollen, after disgorging the + honey in the centre of the heap of flour already collected. If the width + of the tube does not admit of this operation, if the insect is obliged to + go out and then come in again backwards in order to place itself in a + favourable posture for the discharge of the pollen, then the reed is too + narrow and the Osmia is rather reluctant to accept it. The middle-sized + reeds and a fortiori the large ones leave the victualler entire liberty of + action; but the former do not exceed the width of a cell, a width agreeing + with the bulk of the future cocoon, whereas the latter, with their + excessive diameter, require more than one chamber on the same floor. + </p> + <p> + When free to choose, the Osmia settles by preference in the small reeds. + Here, the work of building is reduced to its simplest expression and + consists in dividing the tube by means of earthen partitions into a + straight row of cells. Against the partition forming the back wall of the + preceding cell the mother places first a heap of honey and pollen; next, + when the portion is seen to be enough, she lays an egg in the centre of + it. Then and then only she resumes her plasterer's work and marks out the + length of the new cell with a mud partition. This partition in its turn + serves as the rear-wall of another chamber, which is first victualled and + then closed; and so on until the cylinder is sufficiently colonized and + receives a thick terminal stopper at its orifice. In a word, the chief + characteristic of this method of nest-building, the roughest of all, is + that the partition in front is not undertaken so long as the victualling + is still incomplete, or, in other words, that the provisions and the egg + are deposited before the Bee sets to work on the partition. + </p> + <p> + At first sight, this latter detail hardly deserves attention: is it not + right to fill the pot before we put a lid on? The Osmia who owns a + medium-sized reed is not at all of this opinion; and other plasterers + share her views, as we shall see when we watch the Odynerus building her + nest. (A genus of Mason-wasps, the essays on which have not yet been + translated into English.—Translator's Note.) Here we have an + excellent illustration of one of those latent powers held in reserve for + exceptional occasions and suddenly brought into play, although often very + far removed from the insect's regular methods. If the reed, without being + of inordinate width from the point of view of the cocoon, is nevertheless + too spacious to afford the Bee a suitable purchase against the wall at the + moment when she is disgorging honey and brushing off her load of pollen; + the Osmia altogether changes the order of her work; she sets up the + partition first and then does the victualling. + </p> + <p> + All round the inside of the tube she places a ring of mud, which, as the + result of her constant visits to the mortar, ends by becoming a complete + diaphragm minus an orifice at the side, a sort of round dog-hole, just + large enough for the insect to pass through. When the cell is thus marked + out and almost wholly closed, the Osmia attends to the storing of her + provisions and the laying of her eggs. Steadying herself against the + margin of the hole at one time with her fore-legs and at another with her + hind-legs, she is able to empty her crop and to brush her abdomen; by + pressing against it, she obtains a foothold for her little efforts in + these various operations. When the tube was narrow, the outer wall + supplied this foothold and the earthen partition was postponed until the + heap of provisions was completed and surmounted by the egg; but in the + present case the passage is too wide and would leave the insect + floundering helplessly in space, so the partition with its serving-hatch + takes precedence of the victuals. This method is a little more expensive + than the other, first in materials, because of the diameter of the reed, + and secondly in time, if only because of the dog-hole, a delicate piece of + mortar-work which is too soft at first and cannot be used until it has + dried and become harder. Therefore the Osmia, who is sparing of her time + and strength, accepts medium-sized reeds only when there are no small ones + available. + </p> + <p> + The large tubes she will use only in grave emergencies and I am unable to + state exactly what these exceptional circumstances are. Perhaps she + decides to make use of those roomy dwellings when the eggs have to be laid + at once and there is no other shelter in the neighbourhood. While my + cylinder-hives gave me plenty of well-filled reeds of the first and second + class, they provided me with but half-a-dozen at most of the third, + notwithstanding my precaution to furnish the apparatus with a varied + assortment. + </p> + <p> + The Osmia's repugnance to big cylinders is quite justified. The work in + fact is longer and more costly when the tubes are wide. An inspection of a + nest constructed under these conditions is enough to convince us. It now + consists not of a string of chambers obtained by simple transverse + partitions, but of a confused heap of clumsy, many-sided compartments, + standing back to back, with a tendency to group themselves in storeys + without succeeding in doing so, because any regular arrangement would mean + that the ceilings possessed a span which it is not in the builder's power + to achieve. The edifice is not a geometrical masterpiece and it is even + less satisfactory from the point of view of economy. In the previous + constructions, the sides of the reed supplied the greater part of the + walls and the work was limited to one partition for each cell. Here, + except at the actual periphery, where the tube itself supplies a + foundation, everything has to be obtained by sheer building: the floor, + the ceiling, the walls of the many-sided compartment are one and all made + of mortar. The structure is almost as costly in materials as that of the + Chalicodoma or the Pelopaeus. + </p> + <p> + It must be pretty difficult, too, when one thinks of its irregularity. + Fitting as best she can the projecting angles of the new cell into the + recessed corners of the cell already built, the Osmia runs up walls more + or less curved, upright or slanting, which intersect one another at + various points, so that each compartment requires a new and complicated + plan of construction, which is very different from the circular-partition + style of architecture, with its row of parallel dividing-disks. Moreover, + in this composite arrangement, the size of the recesses left available by + the earlier work to some extent decides the assessment of the sexes, for, + according to the dimensions of those recesses, the walls erected take in + now a larger space, the home of a female, and now a smaller space, the + home of a male. Roomy quarters therefore have a double drawback for the + Osmia: they greatly increase the outlay in materials; and also they + establish in the lower layers, among the females, males who, because of + their earlier hatching, would be much better placed near the mouth of the + nest. I am convinced of it: if the Osmia refuses big reeds and accepts + them only in the last resort, when there are no others, it is because she + objects to additional labour and to the mixture of the sexes. + </p> + <p> + The Snail-shell, then, is but an indifferent home for her, which she is + quite ready to abandon should a better offer. Its expanding cavity + represents an average between the favourite small cylinder and the + unpopular large cylinder, which is accepted only when there is no other + obtainable. The first whorls of the spiral are too narrow to be of use to + the Osmia, but the middle ones have the right diameter for cocoons + arranged in single file. Here things happen as in a first-class reed, for + the helical curve in no way affects the method of structure employed for a + rectilinear series of cells. Circular partitions are erected at the + required distances, with or without a serving-hatch, according to the + diameter. These mark out the first cells, one after the other, which are + reserved solely for the females. Then comes the last whorl, which is much + too wide for a single row of cells; and here we once more find, exactly as + in a wide reed, a costly profusion of masonry, an irregular arrangement of + the cells and a mixture of the sexes. + </p> + <p> + Having said so much, let us go back to the Osmia of the quarries. Why, + when I offer them simultaneously Snail-shells and reeds of a suitable + size, do the old frequenters of the shells prefer the reeds, which in all + probability have never before been utilized by their race? Most of them + scorn the ancestral dwelling and enthusiastically accept my reeds. Some, + it is true, take up their quarters in the Snail-shell; but even among + these a goodly number refuse my new shells and return to their + birth-place, the old Snail-shell, in order to utilize the family property, + without much labour, at the cost of a few repairs. Whence, I ask, comes + this general preference for the cylinder, never used hitherto? The answer + can be only this: of two lodgings at her disposal the Osmia selects the + one that provides a comfortable home at a minimum outlay. She economizes + her strength when restoring an old nest; she economizes it when replacing + the Snail-shell by the reed. + </p> + <p> + Can animal industry, like our own, obey the law of economy, the sovran law + that governs our industrial machine even as it governs, at least to all + appearances, the sublime machine of the universe? Let us go deeper into + the question and bring other workers into evidence, those especially who, + better equipped perhaps and at any rate better fitted for hard work, + attack the difficulties of their trade boldly and look down upon alien + establishments with scorn. Of this number are the Chalicodomae, the + Mason-bees proper. + </p> + <p> + The Mason-bee of the Pebbles does not make up her mind to build a + brand-new dome unless there be a dearth of old and not quite dilapidated + nests. The mothers, sisters apparently and heirs-at-law to the domain, + dispute fiercely for the ancestral abode. The first who, by sheer brute + force, takes possession of the dome, perches upon it and, for long hours, + watches events while polishing her wings. If some claimant puts in an + appearance, forthwith the other turns her out with a volley of blows. In + this way the old nests are employed so long as they have not become + uninhabitable hovels. + </p> + <p> + Without being equally jealous of the maternal inheritance, the Mason-bee + of the Sheds eagerly uses the cells whence her generation issued. The work + in the huge city under the eaves begins thus: the old cells, of which, by + the way, the good-natured owner yields a portion to Latreille's Osmia and + to the Three-horned Osmia alike, are first made clean and wholesome and + cleared of broken plaster and then provisioned and shut. When all the + accessible chambers are occupied, the actual building begins with a new + stratum of cells upon the former edifice, which becomes more and more + massive from year to year. + </p> + <p> + The Mason-bee of the Shrubs, with her spherical nests hardly larger than + walnuts, puzzled me at first. Does she use the old buildings or does she + abandon them for good? To-day perplexity makes way for certainty: she uses + them very readily. I have several times surprised her lodging her family + in the empty rooms of a nest where she was doubtless born herself. Like + her kinswoman of the Pebbles, she returns to the native dwelling and + fights for its possession. Also, like the dome-builder, she is an + anchorite and prefers to cultivate the lean inheritance alone. Sometimes, + however, the nest is of exceptional size and harbours a crowd of + occupants, who live in peace, each attending to her business, as in the + colossal hives in the sheds. Should the colony be at all numerous and the + estate descend to two or three generations in succession, with a fresh + layer of masonry each year, the normal walnut-sized nest becomes a ball as + large as a man's two fists. I have gathered on a pine-tree a nest of the + Mason-bee of the Shrubs that weighed a kilogram (2.205 pounds avoirdupois.—Translator's + Note.) and was the size of a child's head. A twig hardly thicker than a + straw served as its support. The casual sight of that lump swinging over + the spot on which I had sat down made me think of the mishap that befell + Garo. (The hero of La Fontaine's fable, "Le Gland et la Citrouille," who + wondered why acorns grew on such tall trees and pumpkins on such low + vines, until he fell asleep under one of the latter and a pumpkin dropped + upon his nose.—Translator's Note.) If such nests were plentiful in + the trees, any one seeking the shade would run a serious risk of having + his head smashed. + </p> + <p> + After the Masons, the Carpenters. Among the guild of wood-workers, the + most powerful is the Carpenter-bee (Xylocopa violacea (Cf. "The Life of + the Spider": chapter 1.—Translator's Note.)), a very large Bee of + formidable appearance, clad in black velvet with violet-coloured wings. + The mother gives her larvae as a dwelling a cylindrical gallery which she + digs in rotten wood. Useless timber lying exposed to the air, vine-poles, + large logs of fire-wood seasoning out of doors, heaped up in front of the + farmhouse porch, stumps of trees, vine-stocks and big branches of all + kinds are her favourite building-yards. A solitary and industrious worker, + she bores, bit by bit, circular passages the width of one's thumb, as + clear-cut as though they were made with an auger. A heap of saw-dust + accumulates on the ground and bears witness to the severity of the task. + Usually, the same aperture is the entrance to two or three parallel + corridors. With several galleries there is accommodation for the entire + laying, though each gallery is quite short; and the Bee thus avoids those + long series which always create difficulties when the moment of hatching + arrives. The laggards and the insects eager to emerge are less likely to + get in each other's way. + </p> + <p> + After obtaining the dwelling, the Carpenter-bee behaves like the Osmia who + is in possession of a reed. Provisions are collected, the egg is laid and + the chamber is walled in front with a saw-dust partition. The work is + pursued in this way until the two or three passages composing the house + are completely stocked. Heaping up provisions and erecting partitions are + an invariable feature of the Xylocopa's programme; no circumstance can + release the mother from the duty of providing for the future of her + family, in the matter both of ready-prepared food and of separate + compartments for the rearing of each larva. It is only in the boring of + the galleries, the most laborious part of the work, that economy can + occasionally be exercised by a piece of luck. Well, is the powerful + Carpenter, all unheeding of fatigue, able to take advantage of such + fortunate occasions? Does she know how to make use of houses which she has + not tunnelled herself? Why, yes: a free lodging suits her just as much as + it does the various Mason-bees. She knows as well as they the economic + advantages of an old nest that is still in good condition: she settles + down, as far as possible, in her predecessors' galleries, after freshening + up the sides with a superficial scraping. And she does better still. She + readily accepts lodgings which have never known a drill, no matter whose. + The stout reeds used in the trellis-work that supports the vines are + valuable discoveries, providing as they do sumptuous galleries free of + cost. No preliminary work or next to none is required with these. Indeed, + the insect does not even trouble to make a side-opening, which would + enable it to occupy the cavity contained within two nodes; it prefers the + opening at the end cut by man's pruning-knife. If the next partition be + too near to give a chamber of sufficient length, the Xylocopa destroys it, + which is easy work, not to be compared with the labour of cutting an + entrance through the side. In this way, a spacious gallery, following on + the short vestibule made by the pruning-knife, is obtained with the least + possible expenditure of energy. + </p> + <p> + Guided by what was happening on the trellises, I offered the black Bee the + hospitality of my reed-hives. From the very beginning, the insect gladly + welcomed my advances; each spring, I see it inspect my rows of cylinders, + pick out the best ones and instal itself there. Its work, reduced to a + minimum by my intervention, is limited to the partitions, the materials + for which are obtained by scraping the inner sides of the reed. + </p> + <p> + As first-rate joiners, next to the Carpenter-bees come the Lithurgi, of + whom my district possesses two species: L. cornutus, FAB., and L. + chrysurus, BOY. By what aberration of nomenclature was the name of + Lithurgus, a worker in stone, given to insects which work solely in wood? + I have caught the first, the stronger of the two, digging galleries in a + large block of oak that served as an arch for a stable-door; I have always + found the second, who is more widely distributed, settling in dead wood—mulberry, + cherry, almond, poplar—that was still standing. Her work is exactly + the same as the Xylocopa's, on a smaller scale. A single entrance-hole + gives access to three or four parallel galleries, assembled in a serried + group; and these galleries are subdivided into cells by means of saw-dust + partitions. Following the example of the big Carpenter-bee, Lithurgus + chrysurus knows how to avoid the laborious work of boring, when occasion + offers: I find her cocoons lodged almost as often in old dormitories as in + new ones. She too has the tendency to economize her strength by turning + the work of her predecessors to account. I do not despair of seeing her + adopt the reed if, one day, when I possess a large enough colony, I decide + to try this experiment on her. I will say nothing about L. cornutus, whom + I only once surprised at her carpentering. + </p> + <p> + The Anthophorae, those children of the precipitous earthy banks, show the + same thrifty spirit as the other members of the mining corporation. Three + species, A. parietina, A. personata and A. pilipes, dig long corridors + leading to the cells, which are scattered here and there and one by one. + These passages remain open at all seasons of the year. When spring comes, + the new colony uses them just as they are, provided that they are well + preserved in the clayey mass baked by the sun; it increases their length + if necessary, runs out a few more branches, but does not decide to start + boring in new ground until the old city, which, with its many labyrinths, + resembles some monstrous sponge, is too much undermined for safety. The + oval niches, the cells that open on those corridors, are also profitably + employed. The Anthophora restores their entrance, which has been destroyed + by the insect's recent emergence; she smooths their walls with a fresh + coat of whitewash, after which the lodging is fit to receive the heap of + honey and the egg. When the old cells, insufficient in number and moreover + partly inhabited by diverse intruders, are all occupied, the boring of new + cells begins, in the extended sections of the galleries, and the rest of + the eggs are housed. In this way, the swarm is settled at a minimum of + expense. + </p> + <p> + To conclude this brief account, let us change the zoological setting and, + as we have already spoken of the Sparrow, see what he can do as a builder. + The simplest form of his nest is the great round ball of straw, dead + leaves and feathers, in the fork of a few branches. It is costly in + material, but can be set up anywhere, when the hole in the wall or the + shelter of a tile are lacking. What reasons induced him to give up the + spherical edifice? To all seeming, the same reasons that led the Osmia to + abandon the Snail-shell's spiral, which requires a fatiguing expenditure + of clay, in favour of the economical cylinder of the reed. By making his + home in a hole in the wall, the Sparrow escapes the greater part of his + work. Here, the dome that serves as a protection from the rain and the + thick walls that offer resistance to the wind both become superfluous. A + mere mattress is sufficient; the cavity in the wall provides the rest. The + saving is great; and the Sparrow appreciates it quite as much as the + Osmia. + </p> + <p> + This does not mean that the primitive art has disappeared, lost through + neglect; it remains an ineffaceable characteristic of the species, ever + ready to declare itself should circumstances demand it. The generations of + to-day are as much endowed with it as the generations of yore; without + apprenticeship, without the example of others, they have within + themselves, in the potential state, the industrial aptitude of their + ancestors. If aroused by the stimulus of necessity, this aptitude will + pass suddenly from inaction to action. When, therefore, the Sparrow still + from time to time indulges in spherical building, this is not progress on + his part, as is sometimes contended; it is, on the contrary, a + retrogression, a return to the ancient customs, so prodigal of labour. He + is behaving like the Osmia who, in default of a reed, makes shift with a + Snail-shell, which is more difficult to utilize but easier to find. The + cylinder and the hole in the wall stand for progress; the spiral of the + Snail-shell and the ball-shaped nest represent the starting-point. + </p> + <p> + I have, I think, sufficiently illustrated the inference which is borne out + by the whole mass of analogous facts. Animal industry manifests a tendency + to achieve the essential with a minimum of expenditure; after its own + fashion, the insect bears witness to the economy of energy. On the one + hand, instinct imposes upon it a craft that is unchangeable in its + fundamental features; on the other hand, it is left a certain latitude in + the details, so as to take advantage of favourable circumstances and + attain the object aimed at with the least possible expenditure of time, + materials and work, the three elements of mechanical labour. The problem + in higher geometry solved by the Hive-bee is only a particular case—true, + a magnificent case,—of this general law of economy which seems to + govern the whole animal world. The wax cells, with their maximum capacity + as against a minimum wall-space, are the equivalent, with the + superaddition of a marvellous scientific skill, of the Osmia's + compartments in which the stonework is reduced to a minimum through the + selection of a reed. The artificer in mud and the artificer in wax obey + the same tendency: they economize. Do they know what they are doing? Who + would venture to suggest it in the case of the Bee grappling with her + transcendental problem? The others, pursuing their rustic art, are no + wiser. With all of them, there is no calculation, no premeditation, but + simply blind obedience to the law of general harmony. + </p> + <p> + <a name="link2HCH0008" id="link2HCH0008"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 8. THE LEAF-CUTTERS. + </h2> + <p> + It is not enough that animal industry should be able, to a certain extent, + to adapt itself to casual exigencies when choosing the site of a nest; if + the race is to thrive, something else is required, something which + hide-bound instinct is unable to provide. The Chaffinch, for instance, + introduces a great quantity of lichen into the outer layer of his nest. + This is his method of strengthening the edifice and making a stout + framework in which to place first the bottom mattress of moss, fine straw + and rootlets and then the soft bed of feathers, wool and down. But, should + the time-honoured lichen be lacking, will the bird refrain from building + its nest? Will it forgo the delight of hatching its brood because it has + not the wherewithal to settle its family in the orthodox fashion? + </p> + <p> + No, the chaffinch is not perplexed by so small a matter; he is an expert + in materials, he understands botanical equivalents. In the absence of the + branches of the evernias, he picks the long beards of the usneas, the + wartlike rosettes of the parmelias, the membranes of the stictises torn + away in shreds; if he can find nothing better, he makes shift with the + bushy tufts of the cladonias. As a practical lichenologist, when one + species is rare or lacking in the neighbourhood, he is able to fall back + on others, varying greatly in shape, colour and texture. And, if the + impossible happened and lichen failed entirely, I credit the Chaffinch + with sufficient talent to be able to dispense with it and to build the + foundations of his nest with some coarse moss or other. + </p> + <p> + What the worker in lichens tells us the other weavers of textile materials + confirm. Each has his favourite flora, which hardly ever varies when the + plant is easily accessible and which can be supplemented by plenty of + others when it is not. The bird's botany would be worth examining; it + would be interesting to draw up the industrial herbal of each species. In + this connection, I will quote just one instance, so as not to stray too + far from the subject in hand. + </p> + <p> + The Red-backed Shrike (Lanius collurio), the commonest variety in my + district, is noteworthy because of his savage mania for forked gibbets, + the thorns in the hedgerows whereon he impales the voluminous contents of + his game-bag—little half-fledged birds, small Lizards, Grasshoppers, + caterpillars, Beetles—and leaves them to get high. To this passion + for the gallows, which has passed unnoticed by the country-folk, at least + in my part, he adds another, an innocent botanical passion, which is so + much in evidence that everybody, down to the youngest bird's-nester, knows + all about it. His nest, a massive structure, is made of hardly any other + materials than a greyish and very fluffy plant, which is found everywhere + among the corn. This is the Filago spathulata of the botanists; and the + bird also makes use, though less frequently, of the Filago germanica, or + common cotton-rose. Both are known in Provencal by the name herbo dou + tarnagas, or Shrike-herb. This popular designation tells us plainly how + faithful the bird is to its plant. To have struck the agricultural + labourer, a very indifferent observer, the Shrike's choice of materials + must be remarkably persistent. + </p> + <p> + Have we here a taste that is exclusive? Not in the least. Though + cotton-roses of all species are plentiful on level ground, they become + scarce and impossible to find on the parched hills. The bird, on its side, + is not given to journeys of exploration and takes what it finds to suit it + in the neighbourhood of its tree or hedge. But on arid ground, the + Micropus erectus, or upright micropus, abounds and is a satisfactory + substitute for the Filago so far as its tiny, cottony leaves and its + little fluffy balls of flowers are concerned. True, it is short and does + not lend itself well to weaver's work. A few long sprigs of another + cottony plant, the Helichrysum staechas, or wild everlasting, inserted + here and there, will give body to the structure. Thus does the Shrike + manage when hard up for his favourite materials: keeping to the same + botanical family, he is able to find and employ substitutes among the fine + cotton-clad stalks. + </p> + <p> + He is even able to leave the family of the Compositae and to go gleaning + more or less everywhere. Here is the result of my botanizings at the + expense of his nests. We must distinguish between two genera in the + Shrike's rough classification: the cottony plants and the smooth plants. + Among the first, my notes mention the following: Convolvulus cantabrica, + or flax-leaved bindweed; Lotus symmetricus, or bird's-foot trefoil; + Teucrium polium, or poly; and the flowery heads of the Phragmites + communis, or common reed. Among the second are these: Medicago lupulina, + or nonesuch; Trifolium repens, or white clover; Lathyrus pratensis, or + meadow lathyrus; Capsella bursa pastoris, or shepherd's purse; Vicia + peregrina, or broad-podded vetch; Convolvulus arvensis, or small bindweed; + Pterotheca nemausensis, a sort of hawkweed; and Poa pratensis, or + smooth-stalked meadow-grass. When it is downy, the plant forms almost the + whole nest, as is the case with the flax-leaved bindweed; when smooth, it + forms only the framework, destined to support a crumbling mass of + micropus, as is the case with the small bindweed. When making this + collection, which I am far from giving as the birds' complete herbarium, I + was struck by a wholly unexpected detail: of the various plants, I found + only the heads still in bud; moreover, all the sprigs, though dry, + possessed the green colouring of the growing plant, a sign of swift + desiccation in the sun. Save in a few cases, therefore, the Shrike does + not collect the dead and withered remains: it is from the growing plants + that he reaps his harvest, mowing them down with his beak and leaving the + sheaves to dry in the sun before using them. I caught him one day hopping + about and pecking at the twigs of a Biscayan bindweed. He was getting in + his hay, strewing the ground with it. + </p> + <p> + The evidence of the Shrike, confirmed by that of all the other workers—weavers, + basket-makers or woodcutters—whom we may care to call as witnesses, + shows us what a large part must be assigned to discernment in the bird's + choice of materials for its nest. Is the insect as highly gifted? When it + works with vegetable matter, is it exclusive in its tastes? Does it know + only one definite plant, its special province? Or has it, for employment + in its manufactures, a varied flora, in which its discernment exercises a + free choice? For answers to these questions we may look, above all, to the + Leaf-cutting Bees, the Megachiles. Reaumur has told the story of their + industry in detail; and I refer the reader who wishes for further + particulars to the master's Memoirs. + </p> + <p> + The man who knows how to use his eyes in his garden will observe, some day + or other, a number of curious holes in the leaves of his lilac- and + rose-trees, some of them round, some oval, as if idle but skilful hands + had been at work with the pinking-iron. In some places, there is scarcely + anything but the veins of the leaves left. The author of the mischief is a + grey-clad Bee, a Megachile. For scissors, she has her mandibles; for + compasses, producing now an oval and anon a circle, she has her eye and + the pivot of her body. The pieces cut out are made into thimble-shaped + wallets, destined to contain the honey and the egg: the larger, oval + pieces supply the floor and sides; the smaller, round pieces are reserved + for the lid. A row of these thimbles, placed one on top of the other, up + to a dozen or more, though often there are less: that is, roughly, the + structure of the Leaf-cutter's nest. + </p> + <p> + When taken out of the recess in which the mother has manufactured it, the + cylinder of cells seems to be an indivisible whole, a sort of tunnel + obtained by lining with leaves some gallery dug underground. The real + thing does not correspond with its appearance: under the least pressure of + the fingers, the cylinder breaks up into equal sections, which are so many + compartments independent of their neighbours as regards both floor and + lid. This spontaneous break up shows us how the work is done. The method + agrees with those adopted by the other Bees. Instead of a general scabbard + of leaves, afterwards subdivided into compartments by transverse + partitions, the Megachile constructs a string of separate wallets, each of + which is finished before the next is begun. + </p> + <p> + A structure of this sort needs a sheath to keep the pieces in place while + giving them the proper shape. The bag of leaves, in fact, as turned out by + the worker, lacks stability; its numerous pieces, not glued together, but + simply placed one after the other, come apart and give way as soon as they + lose the support of the tunnel that keeps them united. Later, when it + spins its cocoon, the larva infuses a little of its fluid silk into the + gaps and solders the pieces to one another, especially the inner ones, so + much so that the insecure bag in due course becomes a solid casket whose + component parts it is no longer possible to separate entirely. + </p> + <p> + The protective sheath, which is also a framework, is not the work of the + mother. Like the great majority of the Osmiae, the Megachiles do not + understand the art of making themselves a home straight away: they want a + borrowed lodging, which may vary considerably in character. The deserted + galleries of the Anthophorae, the burrows of the fat Earth-worms, the + tunnels bored in the trunks of trees by the larva of the Cerambyx-beetle + (The Capricorn, the essay on which has not yet been published in English.—Translator's + Note.), the ruined dwellings of the Mason-bee of the Pebbles, the + Snail-shell nests of the Three-horned Osmia, reed-stumps, when these are + handy, and crevices in the walls are all so many homes for the + Leaf-cutters, who choose this or that establishment according to the + tastes of their particular genus. + </p> + <p> + For the sake of clearness, let us cease generalizing and direct our + attention to a definite species. I first selected the White-girdled + Leaf-cutter (Megachile albocincta, PEREZ), not on account of any + exceptional peculiarities, but solely because this is the Bee most often + mentioned in my notes. Her customary dwelling is the tunnel of an + Earth-worm opening on some clay bank. Whether perpendicular or slanting, + this tunnel runs down to an indefinite depth, where the climate would be + too damp for the Bee. Besides, when the time comes for the hatching of the + adult insect, its emergence would be fraught with peril if it had to climb + up from a deep pit through crumbling rubbish. The Leaf-cutter, therefore, + uses only the front portion of the Worm's gallery, two decimetres at most. + (7.8 inches.—Translator's Note.) What is to be done with the rest of + the tunnel? It is an ascending shaft, tempting to an enemy; and some + underground ravager might come this way and destroy the nest by attacking + the row of cells at the back. + </p> + <p> + The danger is foreseen. Before fashioning her first honey-bag, the Bee + blocks the passage with a strong barricade composed of the only materials + used in the Leaf-cutter's guild. Fragments of leaves are piled up in no + particular order, but in sufficient quantities to make a serious obstacle. + It is not unusual to find in the leafy rampart some dozens of pieces + rolled into screws and fitting into one another like a stack of + cylindrical wafers. For this work of fortification, artistic refinement + seems superfluous; at any rate, the pieces of leaves are for the most part + irregular. You can see that the insect has cut them out hurriedly, + unmethodically and on a different pattern from that of the pieces intended + for the cells. + </p> + <p> + I am struck with another detail in the barricade. Its constituents are + taken from stout, thick, strong-veined leaves. I recognize young + vine-leaves, pale-coloured and velvety; the leaves of the whitish + rock-rose (Cistus albidus), lined with a hairy felt; those of the + holm-oak, selected among the young and bristly ones; those of the + hawthorn, smooth but tough; those of the cultivated reed, the only one of + the Monocotyledones exploited, as far as I know, by the Megachiles. In the + construction of cells, on the other hand, I see smooth leaves + predominating, notably those of the wild briar and of the common acacia, + the robinia. It would appear, therefore, that the insect distinguishes + between two kinds of materials, without being an absolute purist and + sternly excluding any sort of blending. The very much indented leaves, + whose projections can be completely removed with a dexterous snip of the + scissors, generally furnish the various layers of the barricade; the + little robinia-leaves, with their fine texture and their unbroken edges, + are better suited to the more delicate work of the cells. + </p> + <p> + A rampart at the back of the Earth-worm's shaft is a wise precaution and + the Leaf-cutter deserves all credit for it; only it is a pity for the + Megachiles' reputation that this protective barrier often protects nothing + at all. Here we see, under a new guise, that aberration of instinct of + which I gave some examples in an earlier chapter. My notes contain + memoranda of various galleries crammed with pieces of leaves right up to + the orifice, which is on a level with the ground, and entirely devoid of + cells, even of an unfinished one. These were ridiculous fortifications, of + no use whatever; and yet the Bee treated the matter with the utmost + seriousness and took infinite pains over her futile task. One of these + uselessly barricaded galleries furnished me with some hundred pieces of + leaves arranged like a stack of wafers; another gave me as many as a + hundred and fifty. For the defence of a tenanted nest, two dozen and even + fewer are ample. Then what was the object of the Leaf-cutter's ridiculous + pile? + </p> + <p> + I wish I could believe that, seeing that the place was dangerous, she made + her heap bigger so that the rampart might be in proportion to the danger. + Then, perhaps, at the moment of starting on the cells, she disappeared, + the victim of an accident, blown out of her course by a gust of wind. But + this line of defence is not admissible in the Megachile's case. The proof + is palpable: the galleries aforesaid are barricaded up to the level of the + ground; there is no room, absolutely none, to lodge even a single egg. + What was her object, I ask again, when she persisted in obstinately piling + up her wafers? Has she really an object? + </p> + <p> + I do not hesitate to say no. And my answer is based upon what the Osmiae + taught me. I have described above how the Three-horned Osmia, towards the + end of her life, when her ovaries are depleted, expends on useless + operations such energy as remains to her. Born a worker, she is bored by + the inactivity of retirement; her leisure requires an occupation. Having + nothing better to do, she sets up partitions; she divides a tunnel into + cells that will remain empty; she closes with a thick plug reeds + containing nothing. Thus is the modicum of strength of her decline + exhausted in vain labours. The other Builder-bees behave likewise. I see + Anthidia laboriously provide numerous bales of cotton to stop galleries + wherein never an egg was laid; I see Mason-bees build and then religiously + close cells that will remain unvictualled and uncolonized. + </p> + <p> + The long and useless barricades then belong to the last hours of the + Megachile's life, when the eggs are all laid; the mother, whose ovaries + are exhausted, persists in building. Her instinct is to cut out and heap + up pieces of leaves; obeying this impulse, she cuts out and heaps up even + when the supreme reason for this labour ceases. The eggs are no longer + there, but some strength remains; and that strength is expended as the + safety of the species demanded in the beginning. The wheels of action go + on turning in the absence of the motives for action; they continue their + movement as though by a sort of acquired velocity. What clearer proof can + we hope to find of the unconsciousness of the animal stimulated by + instinct? + </p> + <p> + Let us return to the Leaf-cutter's work under normal conditions. + Immediately after a protective barrier comes the row of cells, which vary + considerably in number, like those of the Osmia in her reed. Strings of + about a dozen are rare; the most frequent consist of five or six. No less + subject to variation is the number of pieces joined to make a cell: pieces + of two kinds, some, the oval ones, forming the honey-pot; others, the + round ones, serving as a lid. I count, on an average, eight to ten pieces + of the first kind. Though all cut on the pattern of an ellipse, they are + not equal in dimensions and come under two categories. The larger, outside + ones are each of them almost a third of the circumference and overlap one + another slightly. Their lower end bends into a concave curve to form the + bottom of the bag. Those inside, which are considerably smaller, increase + the thickness of the sides and fill up the gaps left by the first. + </p> + <p> + The Leaf-cutter therefore is able to use her scissors according to the + task before her: first, the large pieces, which help the work forward, but + leave empty spaces; next, the small pieces, which fit into the defective + portions. The bottom of the cell particularly comes in for after-touches. + As the natural curve of the larger pieces is not enough to provide a cup + without cracks in it, the Bee does not fail to improve the work with two + or three small oval pieces applied to the imperfect joins. + </p> + <p> + Another advantage results from the snippets of unequal size. The three or + four outer pieces, which are the first placed in position, being the + longest of all, project beyond the mouth, whereas the next, being shorter, + do not come quite up to it. A brim is thus obtained, a ledge on which the + round disks of the lid rest and are prevented from touching the honey when + the Bee presses them into a concave cover. In other words, at the mouth + the circumference comprises only one row of leaves; lower down it takes + two or three, thus restricting the diameter and securing an hermetic + closing. + </p> + <p> + The cover of the pot consists solely of round pieces, very nearly alike + and more or less numerous. Sometimes I find only two, sometimes I count as + many as ten, closely stacked. At times, the diameter of these pieces is of + an almost mathematical precision, so much so that the edges of the disk + rest upon the ledge. No better result would be obtained had they been cut + out with the aid of compasses. At times, again, the piece projects + slightly beyond the mouth, so that, to enter, it has to be pressed down + and curved cupwise. There is no variation in the diameter of the first + pieces placed in position, those nearest to the honey. They are all of the + same size and thus form a flat cover which does not encroach on the cell + and will not afterwards interfere with the larva, as a convex ceiling + would. The subsequent disks, when the pile is numerous, are a little + larger; they only fit the mouth by yielding to pressure and becoming + concave. The Bee seems to make a point of this concavity, for it serves as + a mould to receive the curved bottom of the next cell. + </p> + <p> + When the row of cells is finished, the task still remains of blocking up + the entrance to the gallery with a safety-stopper similar to the earthen + plug with which the Osmia closes her reeds. The Bee then returns to the + free and easy use of the scissors which we noticed at the beginning when + she was fencing off the back part of the Earth-worm's too deep burrow; she + cuts out of the foliage irregular pieces of different shapes and sizes and + often retaining their original deeply-indented margins; and with all these + pieces, very few of which fit at all closely the orifice to be blocked, + she succeeds in making an inviolable door, thanks to the huge number of + layers. + </p> + <p> + Let us leave the Leaf-cutter to finish depositing her eggs in other + galleries, which will be colonized in the same manner, and consider for a + moment her skill as a cutter. Her edifices consist of a multitude of + fragments belonging to three categories: oval pieces for the sides of the + cells; round pieces for the lids; and irregular pieces for the barricades + at the front and back. The last present no difficulty: the Bee obtains + them by removing from the leaf some projecting portion, as it stands, a + serrate lobe which, owing to its notches, shortens the insect's task and + lends itself better to scissor-work. So far, there is nothing to deserve + attention: it is unskilled labour, in which an inexperienced apprentice + might excel. + </p> + <p> + With the oval pieces, it becomes another matter. What model has the + Megachile when cutting her neat ellipses out of the delicate material for + her wallets, the robinia-leaves? What mental pattern guides her scissors? + What system of measurement tells her the dimensions? One would like to + picture the insect as a living pair of compasses, capable of tracing an + elliptic curve by a certain natural inflexion of its body, even as our arm + traces a circle by swinging from the shoulder. A blind mechanism, the mere + outcome of its organization, would alone be responsible for its geometry. + This explanation would tempt me if the large oval pieces were not + accompanied by much smaller ones, also oval, which are used to fill the + empty spaces. A pair of compasses which changes its radius of its own + accord and alters the curve according to the plan before it appears to me + an instrument somewhat difficult to believe in. There must be something + better than that. The circular pieces of the lid suggest it to us. + </p> + <p> + If, by the mere flexion inherent in her structure, the Leaf-cutter + succeeds in cutting out ovals, how does she succeed in cutting out rounds? + Can we admit the presence of other wheels in the machinery for the new + pattern, so different in shape and size? Besides, the real point of the + difficulty does not lie there. These rounds, for the most part, fit the + mouth of the jar with almost exact precision. When the cell is finished, + the Bee flies hundreds of yards away to make the lid. She arrives at the + leaf from which the disk is to be cut. What picture, what recollection has + she of the pot to be covered? Why, none at all: she has never seen it; she + does her work underground, in utter darkness! At the utmost, she can have + the indications of touch: not actual indications, of course, for the pot + is not there, but past indications, useless in a work of precision. And + yet the disk to be cut out must have a fixed diameter: if it were too + large, it would not go in; if too small, it would close badly, it would + slip down on the honey and suffocate the egg. How shall it be given its + correct dimensions without a pattern? The Bee does not hesitate for a + moment. She cuts out her disk with the same celerity which she would + display in detaching any shapeless lobe that might do for a stopper; and + that disk, without further measurement, is of the right size to fit the + pot. Let whoso will explain this geometry, which in my opinion is + inexplicable, even when we allow for memory begotten of touch and sight. + </p> + <p> + One winter evening, as we were sitting round the fire, whose cheerful + blaze unloosed our tongues, I put the problem of the Leaf-cutter to my + family: + </p> + <p> + 'Among your kitchen-utensils,' I said, 'you have a pot in daily use; but + it has lost its lid, which was knocked over and broken by the Tomcat + playing among the shelves. To-morrow is market-day and one of you will be + going to Orange to buy the week's provisions. Would she undertake, without + a measure of any kind, with the sole aid of memory, which we would allow + her to refresh before starting by a careful examination of the object, to + bring back exactly what the pot wants, a lid neither too large nor too + small, in short the same size as the top?' + </p> + <p> + It was admitted with one accord that nobody would accept such a commission + without taking a measure with her, or at least a bit of string giving the + width. Our memory for sizes is not accurate enough. She would come back + from the town with something that 'might do'; and it would be the merest + chance if this turned out to be the right size. + </p> + <p> + Well, the Leaf-cutter is even less well-off than ourselves. She has no + mental picture of her pot, because she has never seen it; she is not able + to pick and choose in the crockery-dealer's heap, which acts as something + of a guide to our memory by comparison; she must, without hesitation, far + away from her home, cut out a disk that fits the top of her jar. What is + impossible to us is child's-play to her. Where we could not do without a + measure of some kind, a bit of string, a pattern or a scrap of paper with + figures upon it, the little Bee needs nothing at all. In housekeeping + matters she is cleverer than we are. + </p> + <p> + One objection was raised. Was it not possible that the Bee, when at work + on the shrub, should first cut a round piece of an approximate diameter, + larger than that of the neck of the jar, and that afterwards, on returning + home, she should gnaw away the superfluous part until the lid exactly + fitted the pot? These alterations made with the model in front of her + would explain everything. + </p> + <p> + That is perfectly true; but are there any alterations? To begin with, it + seems to me hardly possible that the insect can go back to the cutting + once the piece is detached from the leaf: it lacks the necessary support + to gnaw the flimsy disk with any precision. A tailor would spoil his cloth + if he had not the support of a table when cutting out the pieces for a + coat. The Megachile's scissors, so difficult to wield on anything not + firmly held, would do equally bad work. + </p> + <p> + Besides, I have better evidence than this for my refusal to believe in the + existence of alterations when the Bee has the cell in front of her. The + lid is composed of a pile of disks whose number sometimes reaches half a + score. Now the bottom part of all these disks is the under surface of the + leaf, which is paler and more strongly veined; the top part is the upper + surface, which is smooth and greener. In other words, the insect places + them in the position which they occupy when gathered. Let me explain. In + order to cut out a piece, the Bee stands on the upper surface of the leaf. + The piece detached is held in the feet and is therefore laid with its top + surface against the insect's chest at the moment of departure. There is no + possibility of its being turned over on the journey. Consequently, the + piece is laid as the Bee has just picked it, with the lower surface + towards the inside of the cell and the upper surface towards the outside. + If alterations were necessary to reduce the lid to the diameter of the + pot, the disk would be bound to get turned over: the piece, manipulated, + set upright, turned round, tried this way and that, would, when finally + laid in position, have its top or bottom surface inside just as it + happened to come. But this is exactly what does not take place. Therefore, + as the order of stacking never changes, the disks are cut, from the first + clip of the scissors, with their proper dimensions. The insect excels us + in practical geometry. I look upon the Leaf-cutter's pot and lid as an + addition to the many other marvels of instinct that cannot be explained by + mechanics; I submit it to the consideration of science; and I pass on. + </p> + <p> + The Silky Leaf-cutter (Megachile sericans, FONSCOL.; M. Dufourii, LEP.) + makes her nests in the disused galleries of the Anthophorae. I know her to + occupy another dwelling which is more elegant and affords a more roomy + installation: I mean the old dwelling of the fat Capricorn, the denizen of + the oaks. The metamorphosis is effected in a spacious chamber lined with + soft felt. When the long-horned Beetle reaches the adult stage, he + releases himself and emerges from the tree by following a vestibule which + the larva's powerful tools have prepared beforehand. When the deserted + cabin, owing to its position, remains wholesome and there is no sign of + any running from its walls, no brown stuff smelling of the tan-yard, it is + soon visited by the Silky Megachile, who finds in it the most sumptuous of + the apartments inhabited by the Leaf-cutters. It combines every condition + of comfort: perfect safety, an even temperature, freedom from damp, ample + room; and so the mother who is fortunate enough to become the possessor of + such a lodging uses it entirely, vestibule and drawing-room alike. + Accommodation is found for all her family of eggs; at least, I have + nowhere seen nests as populous as here. + </p> + <p> + One of them provides me with seventeen cells, the highest number appearing + in my census of the Megachile clan. Most of them are lodged in the nymphal + chamber of the Capricorn; and, as the spacious recess is too wide for a + single row, the cells are arranged in three parallel series. The + remainder, in a single string, occupy the vestibule, which is completed + and filled up by the terminal barricade. In the materials employed, + hawthorn-and paliurus-leaves predominate. The pieces, both in the cells + and in the barrier, vary in size. It is true that the hawthorn-leaves, + with their deep indentations, do not lend themselves to the cutting of + neat oval pieces. The insect seems to have detached each morsel without + troubling overmuch about the shape of the piece, so long as it was big + enough. Nor has it been very particular about arranging the pieces + according to the nature of the leaf: after a few bits of paliurus come + bits of vine and hawthorn; and these again are followed by bits of bramble + and paliurus. The Bee has collected her pieces anyhow, taking a bit here + and there, just as her fancy dictated. Nevertheless, paliurus is the + commonest, perhaps for economical reasons. + </p> + <p> + I notice, in fact, that the leaves of this shrub, instead of being used + piecemeal, are employed whole, when they do not exceed the proper + dimensions. Their oval form and their moderate size suit the insect's + requirements; and there is therefore no necessity to cut them into pieces. + The leaf-stalk is clipped with the scissors and, without more ado, the + Megachile retires the richer by a first-rate bit of material. + </p> + <p> + Split up into their component parts, two cells give me altogether + eighty-three pieces of leaves, whereof eighteen are smaller than the + others and of a round shape. The last-named come from the lids. If they + average forty-two each, the seventeen cells of the nest represent seven + hundred and fourteen pieces. These are not all: the nest ends, in the + Capricorn's vestibule, with a stout barricade in which I count three + hundred and fifty pieces. The total therefore amounts to one thousand and + sixty-four. All those journeys and all that work with the scissors to + furnish the deserted chamber of the Cerambyx! If I did not know the + Leaf-cutter's solitary and jealous disposition, I should attribute the + huge structure to the collaboration of several mothers; but there is no + question of communism in this case. One dauntless creature and one alone, + one solitary, inveterate worker, has produced the whole of the prodigious + mass. If work is the best way to enjoy life, this one certainly has not + been bored during the few weeks of her existence. + </p> + <p> + I gladly award her the most honourable of eulogies, that due to the + industrious; and I also compliment her on her talent for closing the + honey-pots. The pieces stacked into lids are round and have nothing to + suggest those of which the cells and the final barricade are made. + Excepting the first, those nearest the honey, they are perhaps cut a + little less neatly than the disks of the White-girdled Leaf-cutter; no + matter: they stop the jar perfectly, especially when there are some ten of + them one above the other. When cutting them, the Bee was as sure of her + scissors as a dressmaker guided by a pattern laid on the stuff; and yet + she was cutting without a model, without having in front of her the mouth + to be closed. To enlarge on this interesting subject would mean to repeat + oneself. All the Leaf-cutters have the same talent for making the lids of + their pots. + </p> + <p> + A less mysterious question than this geometrical problem is that of the + materials. Does each species of Megachile keep to a single plant, or has + it a definite botanical domain wherein to exercise its liberty of choice? + The little that I have already said is enough to make us suspect that the + insect is not restricted to one plant; and this is confirmed by an + examination of the separate cells, piece by piece, when we find a variety + which we were far from imagining at first. Here is the flora of the + Megachiles in my neighbourhood, a very incomplete flora and doubtless + capable of considerable amplification by future researches. + </p> + <p> + The Silky Leaf-cutter gathers the materials for her pots, her lids and her + barricades from the following plants: paliurus, hawthorn, vine, wild + briar, bramble, holm-oak, amelanchier, terebinthus, sage-leaved rock-rose. + The first three supply the greater part of the leaf-work; the last three + are represented only by rare fragments. + </p> + <p> + The Hare-footed Leaf-cutter (Megachile lagopoda, LIN.) which I see very + busy in my enclosure, though she only collects her materials there, + exploits the lilac and the rose-tree by preference. From time to time, I + see her also cutting bits out of the robinia, the quince-tree and the + cherry-tree. In the open country, I have found her building with the + leaves of the vine alone. + </p> + <p> + The Silvery Leaf-cutter (Megachile argentata, FAB.), another of my guests, + shares the taste of the aforesaid for the lilac and the rose, but her + domain includes in addition the pomegranate-tree, the bramble, the vine, + the common dogwood and the cornelian cherry. + </p> + <p> + The White-girdled Leaf-cutter likes the robinia, to which she adds, in + lavish proportions, the vine, the rose and the hawthorn and sometimes, in + moderation, the reed and the whitish-leaved rock-rose. + </p> + <p> + The Black-tipped Leaf-cutter (Megachile apicalis, SPIN.) has for her abode + the cells of the Mason-bee of the Pebbles and the ruined nests of the + Osmiae and Anthidia in the Snail-shells. I have not known her to use any + other materials than the wild briar and the hawthorn. + </p> + <p> + Incomplete though it be, this list tells us that the Megachiles do not + have exclusive botanical tastes. Each species manages extremely well with + several plants differing greatly in appearance. The first condition to be + fulfilled by the shrub exploited is that it be near the nest. Frugal of + her time, the Leaf-cutter declines to go on distant expeditions. Whenever + I come upon a recent Megachile-nest, I am not long in finding in the + neighbourhood, without much searching, the tree or shrub from which the + Bee has cut her pieces. + </p> + <p> + Another main condition is a fine and supple texture, especially for the + first disks used in the lid and for the pieces which form the lining of + the wallet. The rest, less carefully executed, allows of coarser stuff; + but even then the piece must be flexible and lend itself to the + cylindrical configuration of the tunnel. The leaves of the rock-roses, + thick and roughly fluted, fulfil this condition unsatisfactorily, for + which reason I see them occurring only at very rare intervals. The insect + has gathered pieces of them by mistake and, not finding them good to use, + has ceased to visit the unprofitable shrub. Stiffer still, the leaf of the + holm-oak in its full maturity is never employed: the Silky Leaf-cutter + uses it only in the young state and then in moderation; she can get her + velvety pieces better from the vine. In the lilac-bushes so zealously + exploited before my eyes by the Hare-footed Leaf-cutter occur a medley of + different shrubs which, from their size and the lustre of their leaves, + should apparently suit that sturdy pinker. They are the shrubby + hare's-ear, the honeysuckle, the prickly butcher's-broom, the box. What + magnificent disks ought to come from the hare's-ear and the honeysuckle! + One could get an excellent piece, without further labour, by merely + cutting the leaf-stalk of the box, as Megachile sericans does with her + paliurus. The lilac-lover disdains them absolutely. For what reason? I + fancy that she finds them too stiff. Would she think differently if the + lilac-bush were not there? Perhaps so. + </p> + <p> + In short, apart from the questions of texture and proximity to the nest, + the Megachile's choice, it seems to me, must depend upon whether a + particular shrub is plentiful or not. This would explain the lavish use of + the vine, an object of widespread cultivation, and of the hawthorn and the + wild briar, which form part of all our hedges. As these are to be found + everywhere, the fact that the different Leaf-cutters make use of them is + no reflection upon a host of equivalents varying according to the + locality. + </p> + <p> + If we had to believe what people tell us about the effects of heredity, + which is said to hand down from generation to generation, ever more firmly + established, the individual habits of those who come before, the + Megachiles of these parts, experienced in the local flora by the long + training of the centuries, but complete novices in the presence of plants + which their race encounters for the first time, ought to refuse as unusual + and suspicious any exotic leaves, especially when they have at hand plenty + of the leaves made familiar by hereditary custom. The question was + deserving of separate study. + </p> + <p> + Two subjects of my observations, the Hare-footed and the Silvery + Leaf-cutter, both of them inmates of my open-air laboratory, gave me a + definite answer. Knowing the points frequented by the two Megachiles, I + planted in their work-yard, overgrown with briar and lilac, two outlandish + plants which seemed to me to fulfil the required conditions of suppleness + of texture, namely, the ailantus, a native of Japan, and the Virginian + physostegia. Events justified the selection: both Bees exploited the + foreign flora with the same assiduity as the local flora, passing from the + lilac to the ailantus, from the briar to the physostegia, leaving the one, + going back to the other, without drawing distinctions between the known + and the unknown. Inveterate habit could not have given greater certainty, + greater ease to their scissors, though this was their first experience of + such a material. + </p> + <p> + The Silvery Leaf-cutter lent herself to an even more conclusive test. As + she readily makes her nest in the reeds of my apparatus, I was able, up to + a certain point, to create a landscape for her and select its vegetation + myself. I therefore moved the reed-hive to a part of the enclosure stocked + chiefly with rosemary, whose scanty foliage is not adapted for the Bee's + work, and near the apparatus I arranged an exotic shrubbery in pots, + including notably the smooth lopezia, from Mexico, and the long-fruited + capsicum, an Indian annual. Finding close at hand the wherewithal to build + her nest, the Leaf-cutter went no further afield. The lopezia suited her + especially, so much so that almost the whole nest was composed of it. The + rest had been gathered from the capsicum. + </p> + <p> + Another recruit, whose co-operation I had in no way engineered, came + spontaneously to offer me her evidence. This was the Feeble Leaf-cutter + (Megachile imbecilla, GERST.). Nearly a quarter of a century ago, I saw + her, all through the month of July, cutting out her rounds and ellipses at + the expense of the petals of the Pelargonium zonale, the common geranium. + Her perseverance devastated—there is no other word for it—my + modest array of pots. Hardly was a blossom out, when the ardent Megachiles + came and scalloped it into crescents. The colour was indifferent to her: + red, white or pink, all the petals underwent the disastrous operation. A + few captures, ancient relics of my collecting-boxes by this time, + indemnified me for the pillage. I have not seen this unpleasant Bee since. + With what does she build when there are no geranium-flowers handy? I do + not know; but the fact remains that the fragile tailoress used to attack + the foreign flower, a fairly recent acquisition from the Cape, as though + all her race had never done anything else. + </p> + <p> + These details leave us with one obvious conclusion, which is contrary to + our original ideas, based on the unvarying character of insect industry. + In constructing their jars, the Leaf-cutters, each following the taste + peculiar to her species, do not make use of this or that plant to the + exclusion of the others; they have no definite flora, no domain faithfully + transmitted by heredity. Their pieces of leaves vary according to the + surrounding vegetation; they vary in different layers of the same cell. + Everything suits them, exotic or native, rare or common, provided that the + bit cut out be easy to employ. It is not the general aspect of the shrub, + with its fragile or bushy branches, its large or small, green or grey, + dull or glossy leaves, that guides the insect: such advanced botanical + knowledge does not enter into the question at all. In the thicket chosen + as a pinking-establishment, the Megachile sees but one thing: leaves + useful for her work. The Shrike, with his passion for plants with long, + woolly sprigs, knows where to find nicely-wadded substitutes when his + favourite growth, the cotton-rose, is lacking; the Megachile has much + wider resources: indifferent to the plant itself, she looks only into the + foliage. If she finds leaves of the proper size, of a dry texture capable + of defying the damp and of a suppleness favourable to cylindrical curving, + that is all she asks; and the rest does not matter. She has therefore an + almost unlimited field for her labour. + </p> + <p> + These sudden and wholly unprovoked changes give cause for reflection. When + my geranium-flowers were devastated, how had the obtrusive Bee, untroubled + by the profound dissimilarity between the petals, snow-white here, bright + scarlet there, how had she learnt her trade? Nothing tells us that she + herself was not for the first time exploiting the plant from the Cape; + and, if she really did have predecessors, the habit had not had time to + become inveterate, considering the modern importation of the geranium. + Where again did the Silvery Megachile, for whom I created an exotic + shrubbery, make the acquaintance of the lopezia, which comes from Mexico? + She certainly is making a first start. Never did her village or mine + possess a stalk of that chilly denizen of our hot-houses. She is making a + first start; and behold her straightway a graduate, versed in the art of + carving unfamiliar foliage. + </p> + <p> + People often talk of the long apprenticeships served by instinct, of its + gradual acquirements, of its talents, the laborious work of the ages. The + Megachiles affirm the exact opposite. They tell me that the animal, though + invariable in the essence of its art, is capable of innovation in the + details; but at the same time they assure me that any such innovation is + sudden and not gradual. Nothing prepares the innovations, nothing improves + them or hands them down; otherwise a selection would long ago have been + made amid the diversity of foliage; and the shrub recognized as the most + serviceable, especially when it is also plentiful, would alone supply all + the building-materials needed. If heredity transmitted industrial + discoveries, a Megachile who thought of cutting her disks out of + pomegranate-leaves and found them satisfactory ought to have instilled a + liking for similar materials into her descendants; and we should this day + find Leaf-cutters faithful to the pomegranate-leaves, workers who remained + exclusive in their choice of the raw material. The facts refute these + theories. + </p> + <p> + People also say: + </p> + <p> + 'Grant us a variation, however small, in the insect's industry; and that + variation, accentuated more and more, will produce a new race and finally + a fixed species.' + </p> + <p> + This trifling variation is the fulcrum for which Archimedes clamoured in + order to lift the world with his system of levers. The Megachiles offer us + one and a very great one: the indefinite variation of their materials. + What will the theorists' levers lift with this fulcrum? Why, nothing at + all! Whether they cut the delicate petals of the geranium or the tough + leaves of the lilac-bushes, the Leaf-cutters are and will be what they + were. This is what we learn from the persistence of each species in its + structural details, despite the great variety of the foliage employed. + </p> + <p> + <a name="link2HCH0009" id="link2HCH0009"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 9. THE COTTON-BEES. + </h2> + <p> + The evidence of the Leaf-cutters proves that a certain latitude is left to + the insect in its choice of materials for the nest; and this is confirmed + by the testimony of the Anthidia, the cotton-manufacturers. My district + possesses five: A. Florentinum, LATR., A. diadema, LATR., A. manicatum, + LATR., A. cingulatum, LATR., A. scapulare, LATR. None of them creates the + refuge in which the cotton goods are manufactured. Like the Osmiae and the + Leaf-cutters, they are homeless vagrants, adopting, each to her own taste, + such shelter as the work of others affords. The Scapular Anthidium is + loyal to the dry bramble, deprived of its pith and turned into a hollow + tube by the industry of various mining Bees, among which figure, in the + front rank, the Ceratinae, dwarf rivals of the Xylocopa, or Carpenter-bee, + that mighty driller of rotten wood. The spacious galleries of the Masked + Anthophora suit the Florentine Anthidium, the foremost member of the genus + so far as size is concerned. The Diadem Anthidium considers that she has + done very well if she inherits the vestibule of the Hairy-footed + Anthophora, or even the ordinary burrow of the Earth-worm. Failing + anything better, she may establish herself in the dilapidated dome of the + Mason-bee of the Pebbles. The Manicate Anthidium shares her tastes. I have + surprised the Girdled Anthidium cohabiting with a Bembex-wasp. The two + occupants of the cave dug in the sand, the owner and the stranger, were + living in peace, both intent upon their business. Her usual habitation is + some hole or other in the crevices of a ruined wall. To these refuges, the + work of others, we can add the stumps of reeds, which are as popular with + the various cotton-gatherers as with the Osmiae; and, after we have + mentioned a few most unexpected retreats, such as the sheath provided by a + hollow brick or the labyrinth furnished by the lock of a gate, we shall + have almost exhausted the list of domiciles. + </p> + <p> + Like the Osmiae and the Leaf-cutters, the Anthidium shows an urgent need + of a ready-made home. She never houses herself at her own expense. Can we + discover the reason? Let us first consult a few hard workers who are + artificers of their own dwellings. The Anthophora digs corridors and cells + in the road-side banks hardened by the sun; she does not erect, she + excavates; she does not build, she clears. Toiling away with her + mandibles, atom by atom, she manages to contrive the passages and chambers + necessary for her eggs; and a huge business it is. She has, in addition, + to polish and glaze the rough sides of her tunnels. What would happen if, + after obtaining a home by dint of long-continued toil, she had next to + line it with wadding, to gather the fibrous down from cottony plants and + to felt it into bags suitable for the honey-paste? The hard-working Bee + would not be equal to producing all these refinements. Her mining calls + for too great an expenditure of time and strength to leave her the leisure + for luxurious furnishing. Chambers and corridors, therefore, will remain + bare. + </p> + <p> + The Carpenter-bee gives us the same answer. When with her joiner's wimble + she has patiently bored the beam to a depth of nine inches, would she be + able to cut out and place in position the thousand and one pieces which + the Silky Leaf-cutter employs for her nest? Time would fail her, even as + it would fail a Megachile who, lacking the Capricorn's chamber, had + herself to dig a home in the trunk of the oak. Therefore the + Carpenter-bee, after the tedious work of boring, gets the installation + done in the most summary fashion, simply running up a sawdust partition. + </p> + <p> + The two things, the laborious business of obtaining a lodging and the + artistic work of furnishing, seem unable to go together. With the insect + as with man, he who builds the house does not furnish it, he who furnishes + it does not build it. To each his share, because of lack of time. Division + of labour, the mother of the arts, makes the workman excel in his + department; one man for the whole work would mean stagnation, the worker + never getting beyond his first crude attempts. Animal industry is a little + like our own: it does not attain its perfection save with the aid of + obscure toilers, who, without knowing it, prepare the final masterpiece. I + see no other reason for this need of a gratuitous lodging for the + Megachile's leafy basket or the Anthidia's cotton purses. In the case of + other artists who handle delicate things that require protection, I do not + hesitate to assume the existence of a ready-made home. Thus Reaumur tells + us of the Upholsterer-bee, Anthocopa papaveris, who fashions her cells + with poppy-petals. I do not know the flower-cutter, I have never seen her; + but her art tells me plainly enough that she must establish herself in + some gallery wrought by others, as, for instance, in an Earth-worm's + burrow. + </p> + <p> + We have but to see the nest of a Cotton-bee to convince ourselves that its + builder cannot at the same time be an indefatigable navvy. When and + newly-felted and not yet made sticky with honey, the wadded purse is by + far the most elegant known specimen of entomological nest-building, + especially where the cotton is of a brilliant white, as is frequently the + case in the manufacturers of the Girdled Anthidium. No bird's-nest, + however deserving of our admiration, can vie in fineness of flock, in + gracefulness of form, in delicacy of felting with this wonderful bag, + which our fingers, even with the aid of tools, could hardly imitate, for + all their dexterity. I abandon the attempt to understand how, with its + little bales of cotton brought up one by one, the insect, no otherwise + gifted than the kneaders of mud and the makers of leafy baskets, manages + to felt what it has collected into a homogeneous whole and then to work + the product into a thimble-shaped wallet. Its tools as a master-fuller are + its legs and its mandibles, which are just like those possessed by the + mortar-kneaders and Leaf-cutters; and yet, despite this similarity of + outfit, what a vast difference in the results obtained! + </p> + <p> + To see the Cotton-bees' talents in action seems an undertaking fraught + with innumerable difficulties: things happen at a depth inaccessible to + the eye; and to persuade the insect to work in the open does not lie in + our power. One resource remained and I did not fail to turn to it, though + hitherto I have been wholly unsuccessful. Three species, Anthidium + diadema, A. manicatum and A. florentinum—the first-named in + particular—show themselves quite ready to take up their abode in my + reed-apparatus. All that I had to do was to replace the reeds by glass + tubes, which would allow me to watch the work without disturbing the + insect. This stratagem had answered perfectly with the Three-horned Osmia + and Latreille's Osmia, whose little housekeeping-secrets I had learnt + thanks to the transparent dwelling-house. Why should it not answer for its + Cotton-bees and, in the same way, with the Leaf-cutters? I almost counted + on success. Events betrayed my confidence. For four years I supplied my + hives with glass tubes and not once did the Cotton-weavers or the + Leaf-cutters condescend to take up their quarters in the crystal palaces. + They always preferred the hovel provided by the reed. Shall I persuade + them one day? I do not abandon all hope. + </p> + <p> + Meanwhile, let me describe the little that I saw. More or less stocked + with cells, the reed is at last closed, right at the orifice, with a thick + plug of cotton, usually coarser than the wadding of the honey-satchels. It + is the equivalent of the Three-horned Osmia's barricade of mud, of the + leaf-putty of Latreille's Osmia, of the Megachiles' barrier of leaves cut + into disks. All these free tenants are careful to shut tight the door of + the dwelling, of which they have often utilized only a portion. To watch + the building of this barricade, which is almost external work, demands but + a little patience in waiting for the favourable moment. + </p> + <p> + The Anthidium arrives at last, carrying the bale of cotton for the + plugging. With her fore-legs she tears it apart and spreads it out; with + her mandibles, which go in closed and come out open, she loosens the hard + lumps of flock; with her forehead she presses each new layer upon the one + below. And that is all. The insect flies off, returns the richer by + another bale and repeats the performance until the cotton barrier reaches + the level of the opening. We have here, remember, a rough task, in no way + to be compared with the delicate manufacturer of the bags; nevertheless, + it may perhaps tell us something of the general procedure of the finer + work. The legs do the carding, the mandibles the dividing, the forehead + the pressing; and the play of these implements produces the wonderful + cushioned wallet. That is the mechanism in the lump; but what of the + artistry? + </p> + <p> + Let us leave the unknown for facts within the scope of observation. I will + question the Diadem Anthidium in particular, a frequent inmate of my + reeds. I open a reed-stump about two decimetres long by twelve millimetres + in diameter. (About seven and three-quarter inches by half an inch.—Translator's + Note.) The end is occupied by a column of cotton-wool comprising ten + cells, without any demarcation between them on the outside, so that their + whole forms a continuous cylinder. Moreover, thanks to a close felting, + the different compartments are soldered together, so much so that, when + pulled by the end, the cotton edifice does not break into sections, but + comes out all in one piece. One would take it for a single cylinder, + whereas in reality the work is composed of a series of chambers, each of + which has been constructed separately, independently of the one before, + except perhaps at the base. + </p> + <p> + For this reason, short of ripping up the soft dwelling, still full of + honey, it is impossible to ascertain the number of storeys; we must wait + until the cocoons are woven. Then our fingers can tell the cells by + counting the knots that resist pressure under the cover of wadding. This + general structure is easily explained. A cotton bag is made, with the + sheath of the reed as a mould. If this guiding sheath were lacking, the + thimble shape would be obtained all the same, with no less elegance, as is + proved by the Girdled Anthidium, who makes her nest in some hiding-place + or other in the walls or the ground. When the purse is finished, the + provisions come and the egg, followed by the closing of the cell. We do + not here find the geometrical lid of the Leaf-cutters, the pile of disks + tight-set in the mouth of the jar. The bag is closed with a cotton sheet + whose edges are soldered by a felting-process to the edges of the opening. + The soldering is so well done that the honey-pouch and its cover form an + indivisible whole. Immediately above it, the second cell is constructed, + having its own base. At the beginning of this work, the insect takes care + to join the two storeys by felting the ceiling of the first to the floor + of the second. Thus continued to the end, the work, with its inner + solderings, becomes an unbroken cylinder, in which the beauties of the + separate wallets disappear from view. In very much the same fashion, but + with less adhesion among the different cells, do the Leaf-cutters act when + stacking their jars in a column without any external division into + storeys. + </p> + <p> + Let us return to the reed-stump which gives us these details. Beyond the + cotton-wool cylinder wherein ten cocoons are lodged in a row comes an + empty space of half a decimetre or more. (About two inches.—Translator's + Note.) The Osmiae and the Leaf-cutters are also accustomed to leave these + long, deserted vestibules. The nest ends, at the orifice of the reed, with + a strong plug of flock coarser and less white than that of the cells. This + use of closing-materials which are less delicate in texture but of greater + resisting-power, while not an invariable characteristic, occurs frequently + enough to make us suspect that the insect knows how to distinguish what is + best suited now to the snug sleeping-berth of the larvae, anon to the + defensive barricade of the home. Sometimes the choice is an exceedingly + judicious one, as is shown by the nest of the Diadem Anthidium. Time after + time, whereas the cells were composed of the finest grade of white cotton, + gathered from Centaurea solsticialis, or St. Barnaby's thistle, the + barrier at the entrance, differing from the rest of the work in its yellow + colouring, was a heap of close-set bristles supplied by the scallop-leaved + mullein. The two functions of the wadding are here plainly marked. The + delicate skin of the larvae needs a well-padded cradle; and the mother + collects the softest materials that the cottony plants provide. Rivalling + the bird, which furnishes the inside of the nest with wool and strengthens + the outside with sticks, she reserves for the grubs' mattress the finest + down, so hard to find and collected with such patience. But, when it + becomes a matter of shutting the door against the foe, then the entrance + bristles with forbidding caltrops, with stiff, prickly hairs. + </p> + <p> + This ingenious system of defence is not the only one known to the + Anthidia. More distrustful still, the Manicate Anthidium leaves no space + in the front part of the reed. Immediately after the column of cells, she + heaps up, in the uninhabited vestibule, a conglomeration of rubbish, + whatever chance may offer in the neighbourhood of the nest: little pieces + of gravel, bits of earth, grains of sawdust, particles of mortar, + cypress-catkins, broken leaves, dry Snail-droppings and any other material + that comes her way. The pile, a real barricade this time, blocks the reed + completely to the end, except about two centimetres (About three-quarters + of an inch.—Translator's Note.) left for the final cotton plug. + Certainly no foe will break in through the double rampart; but he will + make an insidious attack from the rear. The Leucopsis will come and, with + her long probe, thanks to some imperceptible fissure in the tube, will + insert her dread eggs and destroy every single inhabitant of the fortress. + Thus are the Manicate Anthidium's anxious precautions outwitted. + </p> + <p> + If we had not already seen the same thing with the Leaf-cutters, this + would be the place to enlarge upon the useless tasks undertaken by the + insect when, with its ovaries apparently depleted, it goes on spending its + strength with no maternal object in view and for the sole pleasure of + work. I have come across several reeds stopped up with flock though + containing nothing at all, or else furnished with one, two or three cells + devoid of provisions or eggs. The ever-imperious instinct for gathering + cotton and felting it into purses and heaping it into barricades persists, + fruitlessly, until life fails. The Lizard's tail wriggles, curls and + uncurls after it is detached from the animal's body. In these reflex + movements, I seem to see not an explanation, certainly, but a rough image + of the industrious persistency of the insect, still toiling away at its + business, even when there is nothing useful left to do. This worker knows + no rest but death. + </p> + <p> + I have said enough about the dwelling of the Diadem Anthidium; let us look + at the inhabitant and her provisions. The honey is pale-yellow, + homogeneous and of a semifluid consistency, which prevents it from + trickling through the porous cotton bag. The egg floats on the surface of + the heap, with the end containing the head dipped into the paste. To + follow the larva through its progressive stages is not without interest, + especially on account of the cocoon, which is one of the most singular + that I know. With this object in view, I prepare a few cells that lend + themselves to observation. I take a pair of scissors, slice a piece off + the side of the cotton-wool purse, so as to lay bare both the victuals and + the consumer, and place the ripped cell in a short glass tube. During the + first few days, nothing striking happens. The little grub, with its head + still plunged in the honey, slakes its thirst with long draughts and waxes + fat. A moment comes...But let us go back a little farther, before + broaching this question of sanitation. + </p> + <p> + Every grub, of whatever kind, fed on provisions collected by the mother + and placed in a narrow cell is subject to conditions of health unknown to + the roving grub that goes where it likes and feeds itself on what it can + pick up. The first, the recluse, is no more able than the second, the + gadabout, to solve the problem of a food which can be entirely + assimilated, without leaving an unclean residue. The second gives no + thought to these sordid matters: any place suits it for getting rid of + that difficulty. But what will the other do with its waste matter, cooped + up as it is in a tiny cell stuffed full of provisions? A most unpleasant + mixture seems inevitable. Picture the honey-eating grub floating on liquid + provisions and fouling them at intervals with its excretions! The least + movement of the hinder-part would cause the whole to amalgamate; and what + a broth that would make for the delicate nursling! No, it cannot be; those + dainty epicures must have some method of escaping these horrors. + </p> + <p> + They all have, in fact, and most original methods at that. Some take the + bull by the horns, so to speak, and, in order not to soil things, refrain + from uncleanliness until the end of the meal: they keep the dropping-trap + closed as long as the victuals are unfinished. This is a radical scheme, + but not in every one's power, it appears. It is the course adopted, for + instance, by the Sphex-wasps and the Anthophora-bees, who, when the whole + of the food is consumed, expel at one shot the residues amassed in the + intestines since the commencement of the repast. + </p> + <p> + Others, the Osmiae in particular, accept a compromise and begin to relieve + the digestive tract when a suitable space has been made in the cell + through the gradual disappearance of the victuals. Others again—more + hurried these—find means of obeying the common law pretty early by + engaging in stercoral manufactures. By a stroke of genius, they make the + unpleasant obstruction into building-bricks. We already know the art of + the Lily-beetle (Crioceris merdigera. Fabre's essay on this insect has not + yet been translated into English; but readers interested in the matter + will find a full description in "An Introduction to Entomology," by + William Kirby, Rector of Barham, and William Spence: letter 21.—Translator's + Note.), who, with her soft excrement, makes herself a coat wherein to keep + cool in spite of the sun. It is a very crude and revolting art, disgusting + to the eye. The Diadem Anthidium belongs to another school. With her + droppings she fashions masterpieces of marquetry and mosaic, which wholly + conceal their base origin from the onlooker. Let us watch her labours + through the windows of my tubes. + </p> + <p> + When the portion of food is nearly half consumed, there begins and goes on + to the end a frequent defecation of yellowish droppings, each hardly the + size of a pin's head. As these are ejected, the grub pushes them back to + the circumference of the cell with a movement of its hinder-part and keeps + them there by means of a few threads of silk. The work of the spinnerets, + therefore, which is deferred in the others until the provisions are + finished, starts earlier here and alternates with the feeding. In this + way, the excretions are kept at a distance, away from the honey and + without any danger of getting mixed with it. They end by becoming so + numerous as to form an almost continuous screen around the larva. This + excremental awning, made half of silk and half of droppings, is the rough + draft of the cocoon, or rather a sort of scaffolding on which the stones + are deposited until they are definitely placed in position. Pending the + piecing together of the mosaic, the scaffolding keeps the victuals free + from all contamination. + </p> + <p> + To get rid of what cannot be flung outside, by hanging it on the ceiling, + is not bad to begin with; but to use it for making a work of art is better + still. The honey has disappeared. Now commences the final weaving of the + cocoon. The grub surrounds itself with a wall of silk, first pure white, + then tinted reddish-brown by means of an adhesive varnish. Through its + loose-meshed stuff, it seizes one by one the droppings hanging from the + scaffold and inlays them firmly in the tissue. The same mode of work is + employed by the Bembex-, Stizus-and Tachytes-wasps and other inlayers, who + strengthen the inadequate woof of their cocoons with grains of sand; only, + in their cotton-wool purses, the Anthidium's grubs substitute for the + mineral particles the only solid materials at their disposal. For them, + excrement takes the place of pebbles. + </p> + <p> + And the work goes none the worse for it. On the contrary: when the cocoon + is finished, any one who had not witnessed the process of manufacture + would be greatly puzzled to state the nature of the workmanship. The + colouring and the elegant regularity of the outer wrapper of the cocoon + suggest some kind of basket-work made with tiny bits of bamboo, or a + marquetry of exotic granules. I too let myself be caught by it in my early + days and wondered in vain what the hermit of the cotton wallet had used to + inlay her nymphal dwelling so prettily withal. To-day, when the secret is + known to me, I admire the ingenuity of the insect capable of obtaining the + useful and the beautiful out of the basest materials. + </p> + <p> + The cocoon has another surprise in store for us. The end containing the + head finishes with a short conical nipple, an apex, pierced by a narrow + shaft that establishes a communication between the inside and the out. + This architectural feature is common to all the Anthidia, to the + resin-workers who will occupy our attention presently, as well as to the + cotton-workers. It is found nowhere outside the Anthidium group. + </p> + <p> + What is the use of this point which the larva leaves bare instead of + inlaying it like the rest of the shell? What is the use of that hole, left + quite open or, at most, closed at the bottom with a feeble grating of + silk? The insect appears to attach great importance to it, from what I + see. In point of fact, I watch the careful work of the apex. The grub, + whose movements the hole enables me to follow, patiently perfects the + lower end of the conical channel, polishes it and gives it an exactly + circular shape; from time to time, it inserts into the passage its two + closed mandibles, whose points project a little way outside; then, opening + them to a definite radius, like a pair of compasses, it widens the + aperture and makes it regular. + </p> + <p> + I imagine, without venturing, however, to make a categorical statement, + that the perforated apex is a chimney to admit the air required for + breathing. Every pupa breathes in its shell, however compact this may be, + even as the unhatched bird breathes inside the egg. The thousands of pores + with which the shell is pierced allow the inside moisture to evaporate and + the outer air to penetrate as and when needed. The stony caskets of the + Bembex- and Stizus-wasps are endowed, notwithstanding their hardness, with + similar means of exchange between the vitiated and the pure atmosphere. + Can the shells of the Anthidia be air-proof, owing to some modification + that escapes me? In any case, this impermeability cannot be attributed to + the excremental mosaic, which the cocoons of the resin-working Anthidia do + not possess, though endowed with an apex of the very best. + </p> + <p> + Shall we find an answer to the question in the varnish with which the + silken fabric is impregnated? I hesitate to say yes and I hesitate to say + no, for a host of cocoons are coated with a similar lacquer though + deprived of communication with the outside air. All said, without being + able at present to account for its necessity, I admit that the apex of the + Anthidia is a breathing-aperture. I bequeath to the future the task of + telling us for what reasons the collectors of both cotton and resin leave + a large pore in their shells, whereas all the other weavers close theirs + completely. + </p> + <p> + After these biological curiosities, it remains for me to discuss the + principal subject of this chapter: the botanical origin of the materials + of the nest. By watching the insect when busy at its harvesting, or else + by examining its manufactured flock under the microscope, I was able to + learn, not without a great expenditure of time and patience, that the + different Anthidia of my neighbourhood have recourse without distinction + to any cottony plant. Most of the wadding is supplied by the Compositae, + particularly the following: Centaurea solsticialis, or St. Barnaby's + thistle; C. paniculata, or panicled centaury; Echinops ritro, or small + globe-thistle; Onopordon illyricum, or Illyrian cotton-thistle; + Helichrysum staechas, or wild everlasting; Filago germanica, or common + cotton-rose. Next come the Labiatae: Marrubium vulgare, or common white + horehound; Ballota fetida, or stinking horehound; Calamintha nepeta, or + lesser calamint; Salvia aethiopis, or woolly sage. Lastly, the Solanaceae: + Verbascum thapsus, or shepherd's club; V. sinuatum, or scollop-leaved + mullein. + </p> + <p> + The Cotton-bees' flora, we see, incomplete as it is in my notes, embraces + plants of very different aspect. There is no resemblance in appearance + between the proud candelabrum of the cotton-thistle, with its red tufts, + and the humble stalk of the globe-thistle, with its sky-blue capitula; + between the plentiful leaves of the mullein and the scanty foliage of the + St. Barnaby's thistle; between the rich silvery fleece of the woolly sage + and the short hairs of the everlasting. With the Anthidium, these clumsy + botanical characteristics do not count; one thing alone guides her: the + presence of cotton. Provided that the plant be more or less well-covered + with soft wadding, the rest is immaterial to her. + </p> + <p> + Another condition, however, has to be fulfilled, apart from the fineness + of the cotton-wool. The plant, to be worth shearing, must be dead and dry. + I have never seen the harvesting done on fresh plants. In this way, the + Bee avoids mildew, which would make its appearance in a mass of hairs + still filled with sap. + </p> + <p> + Faithful to the plant recognized as yielding good results, the Anthidium + arrives and resumes her gleaning on the edges of the parts denuded by + earlier harvests. Her mandibles scrape away and pass the tiny fluffs, one + by one, to the hind-legs, which hold the pellet pressed against the chest, + mix with it the rapidly-increasing store of down and make the whole into a + little ball. When this is the size of a pea, it goes back into the + mandibles; and the insect flies off, with its bale of cotton in its mouth. + If we have the patience to wait, we shall see it return to the same point, + at intervals of a few minutes, so long as the bag is not made. The + foraging for provisions will suspend the collecting of cotton; then, next + day or the day after, the scraping will be resumed on the same stalk, on + the same leaf, if the fleece be not exhausted. The owner of a rich crop + appears to keep to it until the closing-plug calls for coarser materials; + and even then this plug is often manufactured with the same fine flock as + the cells. + </p> + <p> + After ascertaining the diversity of cotton-fields among our native plants, + I naturally had to enquire whether the Cotton-bee would also put up with + exotic plants, unknown to her race; whether the insect would show any + hesitation in the presence of woolly plants offered for the first time to + the rakes of her mandibles. The common clary and the Babylonian centaury, + with which I have stocked the harmas, shall be the harvest-fields; the + reaper shall be the Diadem Anthidium, the inmate of my reeds. + </p> + <p> + The common clary, or toute-bonne, forms part, I know, of our French flora + to-day; but it is an acclimatized foreigner. They say that a gallant + crusader, returning from Palestine with his share of glory and bruises, + brought back the toute-bonne from the Levant to help him cure his + rheumatism and dress his wounds. From the lordly manor, the plant + propagated itself in all directions, while remaining faithful to the walls + under whose shelter the noble dames of yore used to grow it for their + unguents. To this day, feudal ruins are its favourite resorts. Crusaders + and manors disappeared; the plant remained. In this case, the origin of + the clary, whether historical or legendary, is of secondary importance. + Even if it were of spontaneous growth in certain parts of France, the + toute-bonne is undoubtedly a stranger in the Vaucluse district. Only once + in the course of my long botanizing-expeditions across the department have + I come upon this plant. It was at Caromb, in some ruins, nearly thirty + years ago. I took a cutting of it; and since then the crusaders' sage has + accompanied me on all my peregrinations. My present hermitage possesses + several tufts of it: but, outside the enclosure, except at the foot of the + walls, it would be impossible to find one. We have, therefore, a plant + that is new to the country for many miles around, a cotton-field which the + Serignan Cotton-bees had never utilized before I came and sowed it. + </p> + <p> + Nor had they ever made use of the Babylonian centaury, which I was the + first to introduce in order to cover my ungrateful stony soil with some + little vegetation. They had never seen anything like the colossal centaury + imported from the region of the Euphrates. Nothing in the local flora, not + even the cotton-thistle, had prepared them for this stalk as thick as a + child's wrist, crowned at a height of nine feet with a multitude of yellow + balls, nor for those great leaves spreading over the ground in an enormous + rosette. What will they do in the presence of such a find? They will take + possession of it with no more hesitation than if it were the humble St. + Barnaby's thistle, the usual purveyor. + </p> + <p> + In fact, I place a few stalks of clary and Babylonian centaury, duly + dried, near the reed-hives. The Diadem Anthidium is not long in + discovering the rich harvest. Straight away the wool is recognized as + being of excellent quality, so much so that, during the three or four + weeks of nest-building, I can daily witness the gleaning, now on the + clary, now on the centaury. Nevertheless the Babylonian plant appears to + be preferred, no doubt because of its whiter, finer and more plentiful + down. I keep a watchful eye on the scraping of the mandibles and the work + of the legs as they prepare the pellet; and I see nothing that differs + from the operations of the insect when gleaning on the globe-thistle and + the St. Barnaby's thistle. The plant from the Euphrates and the plant from + Palestine are treated like those of the district. + </p> + <p> + Thus we find what the Leaf-cutters taught us proved, in another way, by + the cotton-gatherers. In the local flora, the insect has no precise + domain; it reaps its harvest readily now from one species, now from + another, provided that it find the materials for its manufactures. The + exotic plant is accepted quite as easily as that of indigenous growth. + Lastly, the change from one plant to another, from the common to the rare, + from the habitual to the exceptional, from the known to the unknown, is + made suddenly, without gradual initiations. There is no novitiate, no + training by habit in the choice of the materials for the nest. The + insect's industry, variable in its details by sudden, individual and + non-transmissible innovations, gives the lie to the two great factors of + evolution: time and heredity. + </p> + <p> + <a name="link2HCH0010" id="link2HCH0010"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 10. THE RESIN-BEES. + </h2> + <p> + At the time when Fabricius (Johann Christian Fabricius (1745-1808), a + noted Danish entomologist, author of "Systema entomologiae" (1775).—Translator's + Note.) gave the genus Anthidium its name, a name still used in our + classifications, entomologists troubled very little about the live animal; + they worked on corpses, a dissecting-room method which does not yet seem + to be drawing to an end. They would examine with a conscientious eye the + antenna, the mandible, the wing, the leg, without asking themselves what + use the insect had made of those organs in the exercise of its calling. + The animal was classified very nearly after the manner adopted in + crystallography. Structure was everything; life, with its highest + prerogatives, intellect, instinct, did not count, was not worthy of + admission into the zoological scheme. + </p> + <p> + It is true that an almost exclusively necrological study is obligatory at + first. To fill one's boxes with insects stuck on pins is an operation + within the reach of all; to watch those same insects in their mode of + life, their work, their habits and customs is quite a different thing. The + nomenclator who lacks the time—and sometimes also the inclination—takes + his magnifying-glass, analyzes the dead body and names the worker without + knowing its work. Hence the number of appellations the least of whose + faults is that they are unpleasant to the ear, certain of them, indeed, + being gross misnomers. Have we not, for instance, seen the name of + Lithurgus, or stone-worker, given to a Bee who works in wood and nothing + but wood? Such absurdities will be inevitable until the animal's + profession is sufficiently familiar to lend its aid in the compiling of + diagnoses. I trust that the future will see this magnificent advance in + entomological science: men will reflect that the impaled specimens in our + collections once lived and followed a trade; and anatomy will be kept in + its proper place and made to leave due room for biology. + </p> + <p> + Fabricius did not commit himself with his expression Anthidium, which + alludes to the love of flowers, but neither did he mention anything + characteristic: as all Bees have the same passion in a very high degree, I + see no reason to treat the Anthidia as more zealous looters than the + others. If he had known their cotton nests, perhaps the Scandinavian + naturalist would have given them a more logical denomination. As for me, + in a language wherein technical parade is out of place, I will call them + the Cotton-bees. + </p> + <p> + The term requires some limiting. To judge by my finds, in fact, the old + genus Anthidium, that of the classifying entomologists, comprises in my + district two very different corporations. One is known to us and works + exclusively in wadding; the other, which we are about to study, works in + resin, without ever having recourse to cotton. Faithful to my extremely + simple principle of defining the worker, as far as possible, by his work, + I will call the members of this guild the Resin-bees. Thus confining + myself to the data supplied by my observations, I divide the Anthidium + group into equal sections, of equal importance, for which I demand special + generic titles; for it is highly illogical to call the carders of wool and + the kneaders of resin by the same name. I surrender to those whom it + concerns the honour of effecting this reform in the orthodox fashion. + </p> + <p> + Good luck, the friend of the persevering, made me acquainted in different + parts of Vaucluse with four Resin-bees whose singular trade no one had yet + suspected. To-day, I find them all four again in my own neighbourhood. + They are the following: Anthidium septemdentatum, LATR., A. bellicosum, + LEP., A. quadrilobum, LEP., and A. Latreillii, LEP. The first two make + their nests in deserted Snail-shells; the other two shelter their groups + of cells sometimes in the ground, sometimes under a large stone. We will + first discuss the inhabitants of the Snail-shell. I made a brief reference + to them in an earlier chapter, when speaking of the distribution of the + sexes. This mere allusion, suggested by a study of a different kind, must + now be amplified. I return to it with fuller particulars. + </p> + <p> + The stone-heaps in the Roman quarries near Serignan, which I have so often + visited in search of the nests of the Osmia who takes up her abode in + Snail-shells, supply me also with the two Resin-bees installed in similar + quarters. When the Field-mouse has left behind him a rich collection of + empty shells scattered all round his hay mattress under the slab, there is + always a hope of finding some Snail-shells plugged with mud and, here and + there, mixed with them, a few Snail-shells closed with resin. The two Bees + work next door to each other, one using clay, the other gum. The + excellence of the locality is responsible for this frequent cohabitation, + shelter being provided by the broken stone from the quarry and lodgings by + the shells which the Mouse has left behind. + </p> + <p> + At places where dead Snail-shells are few and far between, as in the + crevices of rustic walls, each Bee occupies by herself the shells which + she has found. But here, in the quarries, our crop will certainly be a + double or even a treble one, for both Resin-bees frequent the same heaps. + Let us, therefore, lift the stones and dig into the mound until the + excessive dampness of the subsoil tells us that it is useless to look + lower down. Sometimes at the moment of removing the first layer, sometimes + at a depth of eighteen inches, we shall find the Osmia's Snail-shell and, + much more rarely, the Resin-bee's. Above all, patience! The job is none of + the most fruitful; nor is it exactly an agreeable one. By dint of turning + over uncommonly jagged stones, our fingertips get hurt, lose their skin + and become as smooth as though we had held them on a grindstone. After a + whole afternoon of this work, our back will be aching, our fingers will be + itching and smarting and we shall possess a dozen Osmia-nests and perhaps + two or three Resin-bees' nests. Let us be content with that. + </p> + <p> + The Osmia's shells can be recognized at once, as being closed at the + orifice with a clay cover. The Anthidium's call for a special examination, + without which we should run a great risk of filling our pockets with + cumbersome rubbish. We find a dead Snail-shell among the stones. Is it + inhabited by the Resin-bee or not? The outside tells us nothing. The + Anthidium's work comes at the bottom of the spiral, a long way from the + mouth; and, though this is wide open, the eye cannot travel far enough + along the winding stair. I hold up the doubtful shell to the light. If it + is completely transparent, I know that it is empty and I put it back to + serve for future nests. If the second whorl is opaque, the spiral contains + something. What does it contain? Earth washed in by the rain? Remnants of + the putrefied Snail? That remains to be seen. With a little pocket-trowel, + the inquisitorial implement which always accompanies me, I make a wide + window in the middle of the final whorl. If I see a gleaming resin floor, + with incrustations of gravel, the thing is settled: I possess an + Anthidium's nest. But, oh the number of failures that go to one success! + The number of windows vainly opened in shells whose bottom is stuffed with + clay or with noisome corpses! Thus picking shells among the overturned + stone-heaps, inspecting them in the sun, breaking into them with the + trowel and nearly always rejecting them, I manage, after repeated + attempts, to obtain my materials for this chapter. + </p> + <p> + The first to hatch is the Seven-pronged Resin-bee (Anthidium + septemdentatum). We see her, in the month of April, lumbering along to the + rubbish-heaps in the quarries and the low boundary-walls, in search of her + Snail-shell. She is a contemporary of the Three-horned Osmia, who begins + operations in the last week of April, and often occupies the same + stone-heap, settling in the next shell. She is well-advised to start work + early and to be on neighbourly terms with the Osmia when the latter is + building; in fact, we shall soon see the terrible dangers to which that + same proximity exposes her dilatory rival in resin-work, Anthidium + bellicosum. + </p> + <p> + The shell adopted in the great majority of cases is that of the Common + Snail, Helix aspersa. It is sometimes of full size, sometimes + half-developed. Helix nemoralis and H. caespitum, which are much smaller, + also supply suitable lodgings; and this would as surely apply to any shell + of sufficient capacity, if the places which I explore possessed others, as + witness a nest which my son Emile has sent me from somewhere near + Marseilles. This time, the Resin-bee is settled in Helix algira, the most + remarkable of our land-shells because of the width and regularity of its + spiral, which is copied from that of the Ammonites. This magnificent nest, + a perfect specimen of both the Snail's work and the Bee's, deserves + description before any other. + </p> + <p> + For a distance of three centimetres (1.17 inches.—Translator's + Note.) from the mouth, the last spiral whorl contains nothing. At this + inconsiderable depth, a partition is clearly seen. The moderate diameter + of the passage accounts for the Anthidium's choice of this site to which + our eye can penetrate. In the common Snail-shell, whose cavity widens + rapidly, the insect establishes itself much farther back, so that, in + order to see the terminal partition, we must, as I have said, make a + lateral inlet. The position of this boundary-ceiling, which may come + farther forward or farther back, depends on the variable diameter of the + passage. The cells of the cocoons require a certain length and a certain + breadth, which the mother finds by going higher up or lower down in the + spiral, according to the shape of the shell. When the diameter is + suitable, the last whorl is occupied up to the orifice, where the final + lid appears, absolutely exposed to view. This is the case with the adult + Helix nemoralis and H. caespitum, and also with the young Common Snail. We + will not linger at present over this peculiarity, the importance of which + will become manifest shortly. + </p> + <p> + Whether in the front or at the back of the spiral slope, the insect's work + ends in a facade of coarse mosaic, formed of small, angular bits of + gravel, firmly cemented with a gum the nature of which has to be + ascertained. It is an amber-coloured material, semi-transparent, brittle, + soluble in spirits of wine and burning with a sooty flame and a strong + smell of resin. From these characteristics it is evident that the Bee + prepares her gum with the resinous drops exuded by the Coniferae. + </p> + <p> + I think that I am even able to name the particular plant, though I have + never caught the insect in the act of gathering its materials. Hard by the + stone-heaps which I turn over for my collections there is a plentiful + supply of brown-berried junipers. Pines are totally absent; and the + cypress only appears occasionally near the houses. Moreover, among the + vegetable remains which we shall see assisting in the protection of the + nest, we often find the juniper's catkins and needles. As the resin-insect + is economical of its time and does not fly far from the quarters familiar + to it, the gum must have been collected on the shrub at whose foot the + materials for the barricade have been gathered. Nor is this merely a local + circumstance, for the Marseilles nest abounds in similar remnants. I + therefore regard the juniper as the regular resin-purveyor, without, + however, excluding the pine, the cypress and other Coniferae when the + favourite shrub is absent. + </p> + <p> + The bits of gravel in the lid are angular and chalky in the Marseilles + nest; they are round and flinty in most of the Serignan nests. In making + her mosaic, the worker pays no heed to the form or colour of its component + parts; she collects indiscriminately anything that is hard enough and not + too large. Sometimes she lights upon treasures that give her work a more + original character. The Marseilles nest shows me, neatly encrusted amid + the bits of gravel, a tiny whole landshell, Pupa cineres. A nest in my own + neighbourhood provides me with a pretty Snail-shell, Helix striata, + forming a rose-pattern in the middle of the mosaic. These little artistic + details remind me of a certain nest of Eumenes Amadei (A Mason-wasp, + forming the subject of an essay which has not yet been published in + English.—Translator's Note.) which abounds in small shells. + Ornamental shell-work appears to number its lovers among the insects. + </p> + <p> + After the lid of resin and gravel, an entire whorl of the spiral is + occupied by a barricade of incongruous remnants, similar to that which, in + the reeds, protects the row of cocoons of the Manicate Cotton-bee. It is + curious to see exactly the same defensive methods employed by two builders + of such different talents, one of whom handles flock, the other gum. The + nest from Marseilles has for its barricade bits of chalky gravel, + particles of earth, fragments of sticks, a few scraps of moss and + especially juniper-catkins and needles. The Serignan nests, installed in + Helix aspersa, have almost the same protective materials. I see bits of + gravel, the size of a lentil, and the catkins and needles of the + brown-berried juniper predominating. Next come the dry excretions of the + Snail and a few rare little land-shells. A similar jumble of more or less + everything found near the nest forms, as we know, the barricade of the + Manicate Cotton-bee, who is also an adept at using the Snail's stercoral + droppings after these have been dried in the sun. Let us observe finally + that these dissimilar materials are heaped together without any cementing, + just as the insect has picked them up. Resin plays no part in the mass; + and we have only to pierce the lid and turn the shell upside down for the + barricade to come dribbling to the ground. To glue the whole thing + together does not enter into the Resin-bee's scheme. Perhaps such an + expenditure of gum is beyond her means; perhaps the barricade, if hardened + into a solid block, would afterwards form an invincible obstacle to the + escape of the youngsters; perhaps again the mass of gravel is an accessory + rampart, run up roughly as a work of secondary importance. + </p> + <p> + Amid these doubtful matters, I see at least that the insect does not look + upon its barricade as indispensable. It employs it regularly in the large + shells, whose last whorl, too spacious to be used, forms an unoccupied + vestibule; it neglects it in the moderate shells, such as Helix nemoralis, + in which the resin lid is level with the orifice. My excavations in the + stone-heaps supply me with an almost equal number of nests with and + without defensive embankments. Among the Cotton-bees, the Manicate + Anthidium is not faithful either to her fort of little sticks and stones; + I know some of her nests in which cotton serves every purpose. With both + of them, the gravel rampart seems useful only in certain circumstances, + which I am unable to specify. + </p> + <p> + On the other side of the outworks of the fortification, the lid and + barricade, are the cells set more or less far down in the spiral, + according to the diameter of the shell. They are bounded back and front by + partitions of pure resin, without any encrustations of mineral particles. + Their number is exceedingly restricted and is usually limited to two. The + front room, which is larger because the width of the passage goes on + increasing, is the abode of a male, superior in size to the other sex; the + less spacious back room contains a female. I have already drawn attention + in an earlier chapter to the wonderful problem submitted for our + consideration by this breaking up of the laying into couples and this + alternation of the males and females. Without calling for other work than + the transverse partitions, the broadening stairway of the Snail-shell thus + furnishes both sexes with house-room suited to their size. + </p> + <p> + The second Resin-bee that inhabits shells, Anthidium bellicosum, hatches + in July and works during the fierce heat of August. Her architecture + differs in no wise from that of her kinswoman of the springtime, so much + so that, when we find a tenanted Snail-shell in a hole in the wall or + under the stones, it is impossible to decide to which of the two species + the nest belongs. The only way to obtain exact information is to break the + shell and split the cocoons in February, at which time the nests of the + summer Resin-bee are occupied by larvae and those of the spring Resin-bee + by the perfect insect. If we shrink from this brutal method, we are still + in doubt until the cocoons open, so great is the resemblance between the + two pieces of work. + </p> + <p> + In both cases, we find the same lodging, Snail-shells of every size and + every kind, just as they happen to come; the same resin lid, the inside + gritty with tiny bits of stone, the outside almost smooth and sometimes + ornamented with little shells; the same barricade—not always present—of + various kinds of rubbish; the same division into two rooms of unequal size + occupied by the two sexes. Everything is identical, down to the purveyor + of the gum, the brown-berried juniper. To say more about the nest of the + summer Resin-bee would be to repeat oneself. + </p> + <p> + There is only one thing that requires further investigation. I do not see + the reason that prompts the two insects to leave the greater part of their + shell empty in front, instead of occupying it entirely up to the orifice + as the Osmia habitually does. As the mother's laying is broken up into + intermittent shifts of a couple of eggs apiece, is it necessary that there + should be a new home for each shift? Is the half-fluid resin unsuitable + for the wide-spanned roofs which would have to be constructed when the + diameter of the helical passage exceeded certain limits? Is the gathering + of the cement too wearisome a task to leave the Bee any strength for + making the numerous partitions which she would need if she utilized the + spacious final whorl? I find no answer to these questions. I note the fact + without interpreting it: when the shell is a large one, the front part, + almost the whole of the last whorl, remains an empty vestibule. + </p> + <p> + To the spring Resin-bee, Anthidium septemdentatum, this less than half + occupied lodging presents no drawbacks. A contemporary of the Osmia, often + her neighbour under the same stone, the gum-worker builds her nest at the + same period as the mud-worker; but there is no fear of mutual + encroachments, for the two Bees, working next door to each other, watch + their respective properties with a jealous eye. If attempts at usurpation + were to be made, the owner of the Snail-shell would know how to enforce + her rights as the first occupant. + </p> + <p> + For the summer Resin-bee, A. bellicosum, the conditions are very + different. At the moment when the Osmia is building, she is still in the + larval, or at most in the nymphal stage. Her abode, which would not be + more absolutely silent if deserted, her shell, with its vast untenanted + porch, will not tempt the earlier Resin-bee, who herself wants apartments + right at the far end of the spiral, but it might suit the Osmia, who knows + how to fill the shell with cells up to the mouth. The last whorl left + vacant by the Anthidium is a magnificent lodging which nothing prevents + the mason from occupying. The Osmia does seize upon it, in fact, and does + so too often for the welfare of the unfortunate late-comer. The final + resin lid takes the place, for the Osmia, of the mud stopper with which + she cuts off at the back the portion of the spiral too narrow for her + labours. Upon this lid she builds her mass of cells in so many storeys, + after which she covers the whole with a thick defensive plug. In short, + the work is conducted as though the Snail-shell contained nothing. + </p> + <p> + When July arrives, this doubly-tenanted house becomes the scene of a + tragic conflict. Those below, on attaining the adult state, burst their + swaddling-bands, demolish their resin partitions, pass through the gravel + barricade and try to release themselves; those above, larvae still or + budding pupae, prisoners in their shells until the following spring, + completely block the way. To force a passage from the far-end of those + catacombs is beyond the strength of the Resin-bee, already weakened by the + effort of breaking out of her own nest. A few of the Osmia's partitions + are damaged, a few cocoons receive slight injuries; and then, worn out + with vain struggles, the captives abandon hope and perish behind the + impregnable wall of earth. And with them perish also certain parasites, + even less fit for the prodigious work of clearance: Zonites and Chryses + (Chrysis flammea), of whom the first are consumers of provisions and the + second of grubs. + </p> + <p> + This lamentable ending of the Resin-bee, buried alive under the Osmia's + walls, is not a rare accident to be passed over in silence or mentioned in + a few words; on the contrary, it happens very often; and its frequency + suggests this thought: the school which sees in instinct an acquired habit + treats the slightest favourable occurrence in the course of animal + industry as the starting-point of an improvement which, transmitted by + heredity and becoming in time more and more accentuated, at last grows + into a settled characteristic common to the whole race. There is, it is + true, a total absence of positive proofs in support of this theory; but it + is stated with a wealth of hypothesis that leaves a thousand loopholes: + 'Granting that...Supposing that...It may be...nothing need prevent us from + believing... It is quite possible...' Thus argued the master; and the + disciples have not yet hit upon anything better. + </p> + <p> + 'If the sky were to fall,' said Rabelais, 'the larks would all be caught.' + </p> + <p> + Yes, but the sky stays up; and the larks go on flying. + </p> + <p> + 'If things happened in such and such a way,' says our friend, 'instinct + may have undergone variations and modifications.' + </p> + <p> + Yes, but are you quite sure that things happened as you say? + </p> + <p> + I banish the word 'if' from my vocabulary. I suppose nothing, I take + nothing for granted; I pluck the brutal fact, the only thing that can be + trusted; I record it and then ask myself what conclusion rests upon its + solid framework. From the fact which I have related we may draw the + following inference: + </p> + <p> + 'You say that any modification profitable to the animal is transmitted + throughout a series of favoured ones who, better equipped with tools, + better endowed with aptitudes, abandon the ancient usages and replace the + primitive species, the victim of the struggle for life. You declare that + once, in the dim distance of the ages, a Bee found herself by accident in + possession of a dead Snail-shell. The safe and peaceful lodging pleased + her fancy. On and on went the hereditary liking; and the Snail-shell + proved more and more agreeable to the insect's descendants, who began to + look for it under the stones, so that later generations, with the aid of + habit, ended by adopting it as the ancestral dwelling. Again by accident, + the Bee happened upon a drop of resin. It was soft, plastic, well-suited + for the partitioning of the Snail-shell; it soon hardened into a solid + ceiling. The Bee tried the resinous gum and benefited by it. Her + successors also benefited by it, especially after improving it. Little by + little, the rubble-work of the lid and of the gravel barricade was + invented: an enormous improvement, of which the race did not fail to take + advantage. The defensive fortification was the finishing-touch to the + original structure. Here we have the origin and development of the + instinct of the Resin-bees who make their home in Snail-shells.' + </p> + <p> + This glorious genesis of insect ways and means lacks just one little + thing: probability. Life everywhere, even among the humble, has two + phases: its share of good and its share of evil. Avoiding the latter and + seeking the former is the rough balance-sheet of life's actions. Animals, + like ourselves, have their portion of the sweet and the bitter: they are + just as anxious to reduce the second as to increase the first; for, with + them as with us, + </p> +<pre xml:space="preserve"> + De malheurs evites le bonheur se compose. + (Bad luck missed is good luck gained.) +</pre> + <p> + If the Bee has so faithfully handed down her casual invention of a resin + nest built inside a Snail-shell, then there is no denying that she must + have just as faithfully handed down the means of averting the terrible + danger of belated hatchings. A few mothers, escaping at rare intervals + from the catacombs blocked by the Osmiae, must have retained a lively + memory, a powerful impression of their desperate struggle through the mass + of earth; they must have inspired their descendants with a dread of those + vast dwellings where the stranger comes afterwards and builds; they must + have taught them by habit the means of safety, the use of the medium-sized + shell, which the nest fills to the mouth. So far as the prosperity of the + race was concerned, the discontinuance of the system of empty vestibules + was far more important than the invention of the barricade, which is not + altogether indispensable: it would have saved them from perishing + miserably, behind impenetrable walls, and would have considerably + increased the numbers of their posterity. + </p> + <p> + Thousands and thousands of experiments have been made throughout the ages + with Snail-shells of average dimensions: the thing is certain, because I + find many of them to-day. Well, have these life-saving experiments, with + their immense importance to the race, become general by hereditary + bequest? Not at all: the Resin-bee persists in using big Snail-shells just + as though her ancestors had never known the danger of the Osmia-blocked + vestibule. Once these facts are duly recognized, the conclusion is + irresistible: it is obvious that, as the insect does not hand down the + casual modification tending towards the avoidance of what is to its + disadvantage, neither does it hand down the modification leading to the + adoption of what is to its advantage. However lively the impression made + upon the mother, the accidental leaves no trace in the offspring. Chance + plays no part in the genesis of the instincts. + </p> + <p> + Next to these tenants of the Snail-shells we have two other Resin-bees who + never come to the shells for a cabin for their nests. They are Anthidium + quadrilobum, LEP., and A. Latreillii, LEP., both exceedingly uncommon in + my district. If we meet them very rarely, however, this may well be due to + the difficulty of seeing them; for they lead extremely solitary and wary + lives. A warm nook under some stone or other; the deserted streets of an + Ant-hill in a sun-baked bank; a Beetle's vacant burrow a few inches below + the ground; in short, a cavity of some sort, perhaps arranged by the Bee's + own care: these are the only establishments which I know them to occupy. + And here, with no other shelter than the cover of the refuge, they build a + mass of cells joined together and grouped into a sphere, which, in the + case of the Four-lobed Resin-bee, attains the size of a man's fist and, in + that of Latreille's Resin-bee, the size of a small apple. + </p> + <p> + At first sight, we remain very uncertain as to the nature of the strange + ball. It is brown, rather hard, slightly sticky, with a bituminous smell. + Outside are encrusted a few bits of gravel, particles of earth, heads of + large-sized Ants. This cannibal trophy is not a sign of barbarous customs: + the Bee does not decapitate Ants to adorn her hut. An inlayer, like her + colleagues of the Snail-shell, she gathers any hard granule near at hand + capable of strengthening her work; and the dried skulls of Ants, which are + frequent around about her abode, are in her eyes building-stones of equal + value to the pebbles. One and all employ whatever they can find without + much seeking. The inhabitant of the shell, in order to construct her + barricade, makes shift with the dry excrement of the nearest Snail; the + denizen of the flat stones and of the roadside banks frequented by the + Ants does what she can with the heads of the defunct and, should these be + lacking, is ready to replace them with something else. Moreover, the + defensive inlaying is slight; we see that the insect attaches no great + importance to it and has every confidence in the stout wall of the home. + </p> + <p> + The material of which the work is made at first suggests some rustic wax, + much coarser than that of the Bumble-bees, or rather some tar of unknown + origin. We think again and then recognize in the puzzling substance the + semitransparent fracture, the quality of becoming soft when exposed to + heat and of burning with a smoky flame, the solubility in spirits of wine—in + short, all the distinguishing characteristics of resin. Here then are two + more collectors of the exudations of the Coniferae. At the points where I + find their nests are Aleppo pines, cypresses, brown-berried junipers and + common junipers. Which of the four supplies the mastic? There is nothing + to tell us. Nor is there anything to explain how the native amber-colour + of the resin is replaced in the work of both Bees by a dark-brown hue + resembling that of pitch. Does the insect collect resin impaired by the + weather, soiled by the sanies of rotten wood? When kneading it, does it + mix some dark ingredient with it? I look upon this as possible, but not as + proved, since I have never seen the Bee collecting her resin. + </p> + <p> + While this point escapes me, another of higher interest appears most + plainly; and that is the large amount of resinous material used in a + single nest, especially in that of Anthidium quadrilobum, in which I have + counted as many as twelve cells. The nest of the Mason-bee of the Pebbles + is hardly more massive. For so costly an establishment, therefore, the + Resin-bee collects her pitch on the dead pine as copiously as the + Mason-bee collects her mortar on the macadamized road. Her workshop no + longer shows us the niggardly partitioning of a Snail-shell with two or + three drops of resin; what we see is the whole building of the house, from + the basement to the roof, from the thick outer walls to the partitions of + the rooms. The cement expended would be enough to divide hundreds of + Snail-shells, wherefore the title of Resin-bee is due first and foremost + to this master-builder in pitch. Honourable mention should be awarded to + A. Latreillii, who rivals her fellow-worker as far as her smaller stature + permits. The other manipulators of resin, those who build partitions in + Snail-shells, come third, a very long way behind. + </p> + <p> + And now, with the facts to support us, let us philosophize a little. We + have here, recognized as of excellent standard by all the expert + classifiers, so fastidious in the arrangement of their lists, a generic + group, called Anthidium, containing two guilds of workers entirely + dissimilar in character: the cotton-fullers and the resin-kneaders. It is + even possible that other species, when their habits are better known, will + come and increase this variety of manufactures. I confine myself to the + little that I know and ask myself in what the manipulator of cotton + differs from the manipulator of resin as regards tools, that is to say, + organs. Certainly, when the genus Anthidium was set down by the + classifiers, they were not wanting in scientific precision: they + consulted, under the lens of the microscope, the wings, the mandibles, the + legs, the harvesting-brush, in short, all the details calculated to assist + the proper delimitation of the group. After this minute examination by the + experts, if no organic differences stand revealed, the reason is that they + do not exist. Any dissimilarity of structure could not escape the accurate + eyes of our learned taxonomists. The genus, therefore, is indeed + organically homogeneous; but industrially it is thoroughly heterogeneous. + The implements are the same and the work is different. + </p> + <p> + That eminent Bordeaux entomologist, Professor Jean Perez, to whom I + communicated the misgivings aroused in my mind by the contradictory nature + of my discoveries, thinks that he has found the solution of the difficulty + in the conformation of the mandibles. I extract the following passage from + his volume, "Les Abeilles": + </p> + <p> + 'The cotton-pressing females have the edge of their mandibles cut out into + five or six little teeth, which make an instrument admirably suited for + scraping and removing the hairs from the epidermis of the plants. It is a + sort of comb or teasel. The resin-kneading females have the edge of the + mandible not toothed, but simply curved; the tip alone, preceded by a + notch which is pretty clearly marked in some species, forms a real tooth; + but this tooth is blunt and does not project. The mandible, in short, is a + kind of spoon perfectly fitted to remove the sticky matter and to shape it + into a ball.' + </p> + <p> + Nothing better could be said to explain the two sorts of industry: in the + one case, a rake which gathers the wool; in the other, a spoon which + scoops up the resin. I should have left it at that and felt quite content + without further investigation, if I had not had the curiosity to open my + boxes and, in my turn, to take a good look, side by side, at the workers + in cement and the workers in cotton. Allow me, my learned master, to + whisper in your ear what I saw. + </p> + <p> + The first that I examine is Anthidium septemdentatum. A spoon: yes, it is + just that. Powerful mandibles, shaped like an isosceles triangle, flat + above, hollowed out below; and no indentations, none whatsoever. A + splendid tool, as you say, for gathering the viscous pellet; quite as + efficacious in its kind of work as is the rake of the toothed mandibles + for gathering cotton. Here certainly is a creature potently-gifted, even + though it be for a poor little task, the scooping up of two or three drops + of glue. + </p> + <p> + Things are not quite so satisfactory with the second Resin-bee of the + Snail-shells, A. bellicosum. I find that she has three teeth to her + mandibles. Still, they are slight and project very little. Let us say that + this does not count, even though the work is exactly the same. With A. + quadrilobum the whole thing breaks down. She, the queen of Resin-bees; + she, who collects a lump of mastic the size of one's fist, enough to + subdivide hundreds of her kinswomen's Snail-shells: well, she, by way of a + spoon, carries a rake! On the wide edges of her mandibles stand four + teeth, as long and pointed as those of the most zealous cotton-gleaner. A. + florentinum, that mighty manufacturer of cotton-goods, can hardly rival + her in respect of combing-tools. And nevertheless, with her toothed + implement, a sort of saw, the Resin-bee collects her great heap of pitch, + load by load; and the material is carried not rigid, but sticky, + half-fluid, so that it may amalgamate with the previous lots and be + fashioned into cells. + </p> + <p> + A. Latreillii, without having a very large implement, also bears witness + to the possibility of heaping up soft resin with a rake; she arms her + mandibles with three or four sharply-cut teeth. In short, out of four + Resin-bees, the only four that I know, one is armed with a spoon, if this + expression be really suited to the tool's function; the three others are + armed with a rake; and it so happens that the most copious heap of resin + is just the work of the rake with the most teeth to it, a tool suited to + the cotton-reapers, according to the views of the Bordeaux entomological + expert. + </p> + <p> + No, the explanation that appealed to me so much at first is not + admissible. The mandible, whether supplied with teeth or not, does not + account at all for the two manufactures. May we, in this predicament, have + recourse to the general structure of the insect, although this is not + distinctive enough to be of much use to us? Not so either; for, in the + same stone-heaps where the Osmia and the two Resin-bees of the + Snail-shells work, I find from time to time another manipulator of mastic + who bears no structural relationship whatever to the genus Anthidium. It + is a small-sized Mason-wasp, Odynerus alpestris, SAUSS. She builds a very + pretty nest with resin and gravel in the shells of the young Common Snail, + of Helix nemoralis and sometimes of Bulimulus radiatus. I will describe + her masterpiece on some other occasion. To one acquainted with the genus + Odynerus, any comparison with the Anthidia would be an inexcusable error. + In larval diet, in shape, in habits, they form two dissimilar groups, very + far removed one from the other. The Anthidia feed their offspring on + honey-bread; the Odyneri feed it on live prey. Well, with her slender + form, her weakly frame, in which the most clear-seeing eye would seek in + vain for a clue to the trade practised, the Alpine Odynerus, the + game-lover, uses pitch in the same way as the stout and massive Resin-bee, + the honey-lover. She even uses it better, for her mosaic of tiny pebbles + is much prettier than the Bee's and no less solid. With her mandibles, + this time neither spoon nor rake, but rather a long forceps slightly + notched at the tip, she gathers her drop of sticky matter as dexterously + as do her rivals with their very different outfit. Her case will, I think, + persuade us that neither the shape of the tool nor the shape of the worker + can explain the work done. + </p> + <p> + I will go further: I ask myself in vain the reason of this or that trade + in the case of a fixed species. The Osmiae make their partitions with mud + or with a paste of chewed leaves; the Mason-bees build with cement; the + Pelopaeus-wasps fashion clay pots; the Megachiles made disks cut from + leaves into urns; the Anthidia felt cotton into purses; the Resin-bees + cement together little bits of gravel with gum; the Carpenter-bees and the + Lithurgi bore holes in timber; the Anthophorae tunnel the roadside slopes. + Why all these different trades, to say nothing of the others? How are they + prescribed for the insect, this one rather than that? + </p> + <p> + I foresee the answer: they are prescribed by the organization. An insect + excellently equipped for gathering and felting cotton is ill-equipped for + cutting leaves, kneading mud or mixing resin. The tool in its possession + decides its trade. + </p> + <p> + This is a very simple explanation, I admit, and one within the scope of + everybody: in itself a sufficient recommendation for any one who has + neither the inclination nor the time to undertake a more thorough + investigation. The popularity of certain speculative views is due entirely + to the easy food which they provide for our curiosity. They save us much + long and often irksome study; they impart a veneer of general knowledge. + There is nothing that achieves such immediate success as an explanation of + the riddle of the universe in a word or two. The thinker does not travel + so fast: content to know little so that he may know something, he limits + his field of search and is satisfied with a scanty harvest, provided that + the grain be of good quality. Before agreeing that the tool determines the + trade, he wants to see things with his own eyes; and what he observes is + far from confirming the sweeping statement. Let us share his doubts for a + moment and look into matters more closely. + </p> + <p> + Franklin left us a maxim which is much to the point here. He said that a + good workman should be able to plane with a saw and to saw with a plane. + The insect is too good a workman not to follow the advice of the sage of + Boston. Its industry abounds in instances where the plane takes the place + of the saw, or the saw of the plane; its dexterity makes good the + inadequacy of the implement. To go no further, have we not just seen + different artisans collecting and using pitch, some with spoons, others + with rakes, others again with pincers? Therefore, with such equipment as + it possesses, the insect would be capable of abandoning cotton for leaves, + leaves for resin, resin for mortar, if some predisposition of talent did + not make it keep to its speciality. + </p> + <p> + These few lines, which are the outcome not of a heedless pen but of mature + reflection, will set people talking of hateful paradoxes. We will let them + talk and we will submit the following proposition to our adversaries: take + an entomologist of the highest merit, a Latreille (Pierre Andre Latreille + (1762-1833), one of the founders of modern entomological science.—Translator's + Note.), for instance, versed in all the details of the structure of + insects but utterly unacquainted with their habits. He knows the dead + insect better than anybody, but he has never occupied himself with the + living insect. As a classifier, he is beyond compare; and that is all. We + ask him to examine a Bee, the first that comes to hand, and to name her + trade from her tools. + </p> + <p> + Come, be honest: could he? Who would dare put him to such a test? Has + personal experience not fully convinced us that the mere examination of + the insect can tell us nothing about its particular industry? The baskets + on its legs and the brush on its abdomen will certainly inform us that it + collects honey and pollen; but its special art will remain an utter + secret, notwithstanding all the scrutiny of the microscope. In our own + industries, the plane denotes the joiner, the trowel the mason, the + scissors the tailor, the needle the seamstress. Are things the same in + animal industry? Just show us, if you please, the trowel that is a certain + sign of the mason-insect, the chisel that is a positive characteristic of + the carpenter-insect, the iron that is an authentic mark of the + pinking-insect; and as you show them, say: + </p> + <p> + 'This one cuts leaves; that one bores wood; that other mixes cement.' + </p> + <p> + And so on, specifying the trade from the tool. + </p> + <p> + You cannot do it, no one can; the worker's speciality remains an + impenetrable secret until direct observation intervenes. Does not this + incapacity, even of the most expert, proclaim loudly that animal industry, + in its infinite variety, is due to other causes besides the possession of + tools? Certainly, each of those specialists requires implements; but they + are rough and ready implements, good for all sorts of purposes, like the + tool of Franklin's workman. The same notched mandible that reaps cotton, + cuts leaves and moulds pitch also kneads mud, scrapes decayed wood and + mixes mortar; the same tarsus that manufactures cotton and disks cut out + of leaves is no less clever at the art of making earthen partitions, clay + turrets and gravel mosaics. + </p> + <p> + What then is the reason of these thousand industries? In the light of + facts, I can see but one: imagination governing matter. A primordial + inspiration, a talent antecedent to the actual form, directs the tool + instead of being subordinate to it. The instrument does not determine the + manner of industry; the tool does not make the workman. At the beginning + there is an object, a plan, in view of which the animal acts, + unconsciously. Have we eyes to see with, or do we see because we have + eyes? Does the function create the organ, or the organ the function? Of + the two alternatives, the insect proclaims the first. It says: + </p> + <p> + 'My industry is not imposed upon me by the implement which I possess; what + I do is to use the implement, such as it is, for the talent with which I + am gifted.' + </p> + <p> + It says to us, in its own way: + </p> + <p> + 'The function has determined the organ; vision is the reason of the eye.' + </p> + <p> + In short, it repeats to us Virgil's profound reflection: + </p> + <p> + 'Mens agitat molem'; 'Mind moves matter.' + </p> + <p> + <a name="link2HCH0011" id="link2HCH0011"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 11. THE POISON OF THE BEE. + </h2> + <p> + I have discussed elsewhere the stings administered by the Wasps to their + prey. Now chemistry comes and puts a spoke in the wheel of our arguments, + telling us that the poison of the Bees is not the same as that of the + Wasps. The Bees' is complex and formed of two elements, acid and alkaline. + The Wasps' possess only the acid element; and it is to this very acidity + and not to the 'so-called' skill of the operators that the preservation of + the provisions is due. (The author's numerous essays on the Wasps will + form the contents of later works. In the meantime, cf. "Insect Life," by + J.H. Fabre, translated by the author of "Mademoiselle Mori": chapters 4 to + 12, and 14 to 18; and "The Life and Love of the Insect," by J. Henri + Fabre, translated by Alexander Teixeira de Mattos: chapters 11, 12 and 17.—Translator's + Note.) + </p> + <p> + Admitting that there is a difference in the nature of the venom, I fail to + see that this has any bearing on the problem in hand. I can inoculate with + various liquids—acids, weak nitric acid, alkalis, ammonia, neutral + bodies, spirits of wine, essence of turpentine—and obtain conditions + similar to those of the victims of the predatory insects, that is to say, + inertia with the persistence of a dull vitality betrayed by the movements + of the mouth-parts and antennae. I am not, of course, invariably + successful, for there is neither delicacy nor precision in my poisoned + needle and the wound which it makes does not bear comparison with the tiny + puncture of the unerring natural sting; but, after all, it is repeated + often enough to put the object of my experiment beyond doubt. I should add + that, to achieve success, we must have a subject with a concentrated + ganglionic column, such as the Weevil, the Buprestis, the Dung-beetle and + others. Paralysis is then obtained with but a single prick, made at the + point which the Cerceris has revealed to us, the point at which the + corselet joins the rest of the thorax. In that case, the least possible + quantity of the acrid liquid is instilled, a quantity too small to + endanger the patient's life. With scattered nervous centres, each + requiring a separate operation, this method is impracticable: the victim + would die of the excess of corrosive fluid. I am quite ashamed to have to + recall these old experiments. Had they been resumed and carried on by + others of greater authority than I, we should have escaped the objections + of chemistry. + </p> + <p> + When light is so easy to obtain, why go in search of scientific obscurity? + Why talk of acid or alkaline reactions, which prove nothing, when it is so + simple to have recourse to facts, which prove everything? Before declaring + that the hunting insects' poison has preservative properties merely + because of its acid qualities, it would have been well to enquire if the + sting of a Bee, with its acid and its alkali, could not perchance produce + the same effects as that of the paralyser, whose skill is categorically + denied. The chemists never gave this a thought. Simplicity is not always + welcome in our laboratories. It is my duty to repair that little omission. + I propose to enquire if the poison of the Bee, the chief of the Apidae, is + suitable for a surgery that paralyses without killing. + </p> + <p> + The enquiry bristles with difficulties, though this is no reason for + abandoning it. First and foremost, I cannot possibly operate with the Bee + just as I catch her. Time after time I make the attempt, without once + succeeding; and patience becomes exhausted. The sting has to penetrate at + a definite point, exactly where the Wasp's sting would have entered. My + intractable captive tosses about angrily and stings at random, never where + I wish. My fingers get hurt even oftener than the patient. I have only one + means of gaining a little control over the indomitable dart; and that is + to cut off the Bee's abdomen with my scissors, to seize the stump + instantly with a fine forceps and to apply the tip at the spot where the + sting is to enter. + </p> + <p> + Everybody knows that the Bee's abdomen needs no orders from the head to go + on drawing its weapon for a few instants longer and to avenge the deceased + before being itself overcome with death's inertia. This vindictive + persistency serves me to perfection. There is another circumstance in my + favour: the barbed sting remains where it is, which enables me to + ascertain the exact spot pierced. A needle withdrawn as soon as inserted + would leave me doubtful. I can also, when the transparency of the tissues + permits, perceive the direction of the weapon, whether perpendicular and + favourable to my plans, or slanting and therefore valueless. Those are the + advantages. + </p> + <p> + The disadvantages are these: the amputated abdomen, though more tractable + than the entire Bee, is still far from satisfying my wishes. It gives + capricious starts and unexpected pricks. I want it to sting here. No, it + balks my forceps and goes and stings elsewhere: not very far away, I + admit; but it takes so little to miss the nerve-centre which we wish to + get at. I want it to go in perpendicularly. No, in the great majority of + cases it enters obliquely and passes only through the epidermis. This is + enough to show how many failures are needed to make one success. + </p> + <p> + Nor is this all. I shall be telling nobody anything new when I recall the + fact that the Bee's sting is very painful. That of the hunting insects, on + the contrary, is in most cases insignificant. My skin, which is no less + sensitive than another's, pays no attention to it: I handle Sphex, + Ammophilae and Scoliae without heeding their lancet-pricks. I have said + this before; I remind the reader of it because of the matter in hand. In + the absence of well-known chemical or other properties, we have really but + one means of comparing the two respective poisons; and that is the amount + of pain produced. All the rest is mystery. Besides, no poison, not even + that of the Rattlesnake, has hitherto revealed the cause of its dread + effects. + </p> + <p> + Acting, therefore, under the instruction of that one guide, pain, I place + the Bee's sting far above that of the predatory insects as an offensive + weapon. A single one of its thrusts must equal and often surpass in + efficaciousness the repeated wounds of the other. For all these reasons—an + excessive display of energy; the variable quantity of the virus inoculated + by a wriggling abdomen which no longer measures the emission by doses; a + sting which I cannot direct as I please; a wound which may be deep or + superficial, the weapon entering perpendicularly or obliquely, touching + the nerve-centres or affecting only the surrounding tissues—my + experiments ought to produce the most varied results. + </p> + <p> + I obtain, in fact, every possible kind of disorder: ataxy, temporary + disablement, permanent disablement, complete paralysis, partial paralysis. + Some of my stricken victims recover; others die after a brief interval. It + would be an unnecessary waste of space to record in this volume my hundred + and one attempts. The details would form tedious reading and be of very + little advantage, as in this sort of study it is impossible to marshal + one's facts with any regularity. I will, therefore, sum them up in a few + examples. + </p> + <p> + A colossal member of the Grasshopper tribe, the most powerful in my + district, Decticus verrucivorus (This Decticus has received its specific + name of verrucivorus, or Wart-eating, because it is employed by the + peasants in Sweden and elsewhere to bite off the warts on their fingers.—Translator's + Note.), is pricked at the base of the neck, on the line of the fore-legs, + at the median point. The prick goes straight down. The spot is the same as + that pierced by the sting of the slayer of Crickets and Ephippigers. (A + species of Green Grasshopper. The Sphex paralyses Crickets and + Grasshoppers to provide food for her grubs. Cf. "Insect Life": chapters 6 + to 12.—Translator's Note.) The giantess, as soon as stung, kicks + furiously, flounders about, falls on her side and is unable to get up + again. The fore-legs are paralysed; the others are capable of moving. + Lying sideways, if not interfered with, the insect in a few moments gives + no signs of life beyond a fluttering of the antennae and palpi, a + pulsation of the abdomen and a convulsive uplifting of the ovipositor; + but, if irritated with a slight touch, it stirs its four hind-legs, + especially the third pair, those with the big thighs, which kick + vigorously. Next day, the condition is much the same, with an aggravation + of the paralysis, which has now attacked the middle-legs. On the day after + that, the legs do not move, but the antennae, the palpi and the ovipositor + continue to flutter actively. This is the condition of the Ephippiger + stabbed three times in the thorax by the Languedocian Sphex. One point + alone is missing, a most important point: the long persistence of a + remnant of life. In fact, on the fourth day, the Decticus is dead; her + dark colour tells me so. + </p> + <p> + There are two conclusions to be drawn from this experiment and it is well + to emphasise them. First, the Bee's poison is so active that a single + dagger-thrust aimed at a nervous centre kills in four days one of the + largest of the Orthoptera (An order of insects including the Grasshoppers, + Locusts, Cockroaches, Mantes and Earwigs, in addition to the Stick- and + Leaf-insects, Termites, Dragon-flies, May-flies, Book-lice and others.—Translator's + Note.), though an insect of powerful constitution. Secondly, the paralysis + at first affects only the legs whose ganglion is attacked; next, it + spreads slowly to the second pair; lastly, it reaches the third. The local + effect is diffused. This diffusion, which might well take place in the + victims of the predatory insects, plays no part in the latters' method of + operation. The egg, which will be laid immediately afterwards, demands the + complete inertia of the prey from the outset. Hence all the nerve-centres + that govern locomotion must be numbed instantaneously by the virus. + </p> + <p> + I can now understand why the poison of the predatory Wasps is + comparatively painless in its effects. If it possessed the strength of + that of the Bee, a single stab would impair the vitality of the prey, + while leaving it for some days capable of violent movements that would be + very dangerous to the huntress and especially to the egg. More moderate in + its action, it is instilled at the different nervous centres, as is the + case more particularly with the caterpillars. (Caterpillars are the prey + of the Ammophila, which administers a separate stab to each of the several + ganglia.—Translator's Note.) In this way, the requisite immobility + is obtained at once; and, notwithstanding the number of wounds, the victim + is not a speedy corpse. To the marvels of the paralysers' talent we must + add one more: their wonderful poison, the strength of which is regulated + by delicate doses. The Bee revenging herself intensifies the virulence of + her poison; the Sphex putting her grubs' provender to sleep weakens it, + reduces it to what is strictly necessary. + </p> + <p> + One more instance of nearly the same kind. I prefer to take my subjects + from among the Orthoptera, which, owing to their imposing size and the + thinness of their skin at the points to be attacked, lend themselves + better than other insects to my delicate manipulations. The armour of a + Buprestis, the fat blubber of a Rosechafer-grub, the contortions of a + caterpillar present almost insuperable obstacles to the success of a sting + which it is not in my power to direct. The insect which I now offer to the + Bee's lancet is the Great Green Grasshopper (Locusta viridissima), the + adult female. The prick is given in the median line of the fore-legs. + </p> + <p> + The effect is overwhelming. For two or three seconds the insect writhes in + convulsions and then falls on its side, motionless throughout, save in the + ovipositor and the antennae. Nothing stirs so long as the creature is left + alone; but, if I tickle it with a hair-pencil, the four hind-legs move + sharply and grip the point. As for the fore-legs, smitten in their + nerve-centre, they are quite lifeless. The same condition is maintained + for three days longer. On the fifth day, the creeping paralysis leaves + nothing free but the antennae waving to and fro and the abdomen throbbing + and lifting up the ovipositor. On the sixth, the Grasshopper begins to + turn brown; she is dead. Except that the vestige of life is more + persistent, the case is the same as that of the Decticus. If we can + prolong the duration, we shall have the victim of the Sphex. + </p> + <p> + But first let us look into the effect of a prick administered elsewhere + than opposite the thoracic ganglia. I cause a female Ephippiger to be + stung in the abdomen, about the middle of the lower surface. The patient + does not seem to trouble greatly about her wound: she clambers gallantly + up the sides of the bell-jar under which I have placed her; she goes on + hopping as before. Better still, she sets about browsing the vine-leaf + which I have given her for her consolation. A few hours pass and the whole + thing is forgotten. She has made a rapid and complete recovery. + </p> + <p> + A second is wounded in three places on the abdomen: in the middle and on + either side. On the first day, the insect seems to have felt nothing; I + see no sign of stiffness in its movements. No doubt it is suffering + acutely; but these stoics keep their troubles to themselves. Next day, the + Ephippiger drags her legs a little and walks somewhat slowly. Two days + more; and, when laid on her back, she is unable to turn over. On the fifth + day, she succumbs. This time, I have exceeded the dose; the shock of + receiving three stabs was too much for her. + </p> + <p> + And so with the others, down to the sensitive Cricket, who, pricked once + in the abdomen, recovers in one day from the painful experience and goes + back to her lettuce-leaf. But, if the wound is repeated a few times, death + ensues within a more or less short period. I make an exception, among + those who pay tribute to my cruel curiosity, of the Rosechafer-grubs, who + defy three and four needle-thrusts. They will collapse suddenly and lie + outstretched, flabby and lifeless; and, just when I am thinking them dead + or paralysed, the hardy creatures will recover consciousness, move along + on their backs (This is the usual mode of progression of the Cetonia- or + Rosechafer-grub. Cf. "The Life and Love of the Insect": chapter 11.—Translator's + Note.), bury themselves in the mould. I can obtain no precise information + from them. True, their thinly scattered cilia and their breastplate of fat + form a palisade and a rampart against the sting, which nearly always + enters only a little way and that obliquely. + </p> + <p> + Let us leave these unmanageable ones and keep to the Orthoperon, which is + more amenable to experiment. A dagger-thrust, we were saying, kills it if + directed upon the ganglia of the thorax; it throws it into a transient + state of discomfort if directed upon another point. It is, therefore, by + its direct action upon the nervous centres that the poison reveals its + formidable properties. + </p> + <p> + To generalize and say that death is always near at hand when the sting is + administered in the thoracic ganglia would be going too far: it occurs + frequently, but there are a good many exceptions, resulting from + circumstances impossible to define. I cannot control the direction of the + sting, the depth attained, the quantity of poison shed; and the stump of + the Bee is very far from making up for my shortcomings. We have here not + the cunning sword-play of the predatory insect, but a casual blow, + ill-placed and ill-regulated. Any accident is possible, therefore, from + the gravest to the mildest. Let us mention some of the more interesting. + </p> + <p> + An adult Praying Mantis (Mantis religiosa, so-called because the toothed + fore-legs, in which it catches and kills its prey, adopt, when folded, an + attitude resembling that of prayer.—Translator's Note.) is pricked + level with the attachment of the predatory legs. Had the wound been in the + centre, I should have witnessed an occurrence which, although I have seen + it many times, still arouses my liveliest emotion and surprise. This is + the sudden paralysis of the warrior's savage harpoons. No machinery stops + more abruptly when the mainspring breaks. As a rule, the inertia of the + predatory legs attacks the others in the course of a day or two; and the + palsied one dies in less than a week. But the present sting is not in the + exact centre. The dart has entered near the base of the right leg, at less + than a millimetre (.039 inch.—Translator's Note.) from the median + point. That leg is paralysed at once; the other is not; and the insect + employs it to the detriment of my unsuspecting fingers, which are pricked + to bleeding-point by the spike at the tip. Not until to-morrow is the leg + which wounded me to-day rendered motionless. This time, the paralysis goes + no farther. The Mantis moves along quite well, with her corselet proudly + raised, in her usual attitude; but the predatory fore-arms, instead of + being folded against the chest, ready for attack, hang lifeless and open. + I keep the cripple for twelve days longer, during which she refuses all + nourishment, being incapable of using her tongs to seize the prey and lift + it to her mouth. The prolonged abstinence kills her. + </p> + <p> + Some suffer from locomotor ataxy. My notes recall an Ephippiger who, + pricked in the prothorax away from the median line, retained the use of + her six limbs without being able to walk or climb for lack of + co-ordination in her movements. A singular awkwardness left her wavering + between going back and going forward, between turning to the right and + turning to the left. + </p> + <p> + Some are smitten with semiparalysis. A Cetonia-grub, pricked away from the + centre on a level with the fore-legs, has her right side flaccid, spread + out, incapable of contracting, while the left side swells, wrinkles and + contracts. Since the left half no longer receives the symmetrical + cooperation of the right half, the grub, instead of curling into the + normal volute, closes its spiral on one side and leaves it wide open on + the other. The concentration of the nervous apparatus, poisoned by the + venom down one side of the body only, a longitudinal half, explains this + condition, which is the most remarkable of all. + </p> + <p> + There is nothing to be gained by multiplying these examples. We have seen + pretty clearly the great variety of results produced by the haphazard + sting of a Bee's abdomen; let us now come to the crux of the matter. Can + the Bee's poison reduce the prey to the condition required by the + predatory Wasp? Yes, I have proved it by experiment; but the proof calls + for so much patience that it seemed to me to suffice when obtained once + for each species. In such difficult conditions, with a poison of excessive + strength, a single success is conclusive proof; the thing is possible so + long as it occurs once. + </p> + <p> + A female Ephippiger is stung at the median point, just a little in front + of the fore-legs. Convulsive movements lasting for a few seconds are + followed by a fall to one side, with pulsations of the abdomen, + flutterings of the antennae and a few feeble movements of the legs. The + tarsi cling firmly to the hair-pencil which I hold out to them. I place + the insect on its back. It lies motionless. Its state is absolutely the + same as that to which the Languedocian Sphex (Cf. "Insect Life": chapter + 10.—Translator's Note.) reduces her Ephippigers. For three weeks on + end, I see repeated in all its details the spectacle to which I have been + accustomed in the victims extracted from the burrows or taken from the + huntress: the wide-open mandibles, the quivering palpi and tarsi, the + ovipositor shuddering convulsively, the abdomen throbbing at long + intervals, the spark of life rekindled at the touch of a pencil. In the + fourth week, these signs of life, which have gradually weakened, + disappear, but the insect still remains irreproachably fresh. At last a + month passes; and the paralysed creature begins to turn brown. It is over; + death has come. + </p> + <p> + I have the same success with a Cricket and also with a Praying Mantis. In + all three cases, from the point of view of long-maintained freshness and + of the signs of life proved by slight movements, the resemblance between + my victim and those of the predatory insects is so great that no Sphex and + no Tachytes would have disowned the product of my devices. My Cricket, my + Ephippiger, my Mantis had the same freshness as theirs; they preserved it + as theirs did for a period amply sufficient to allow of the grubs' + complete evolution. They proved to me, in the most conclusive manner, they + prove to all whom it may interest, that the poison of the Bees, leaving + its hideous violence on one side, does not differ in its effects from the + poison of the predatory Wasps. Are they alkaline or acid? The question is + an idle one in this connection. Both of them intoxicate, derange, torpify + the nervous centres and thus produce either death or paralysis, according + to the method of inoculation. For the moment, that is all. No one is yet + able to say the last word on the actions of those poisons, so terrible in + infinitesimal doses. But on the point under discussion we need no longer + be ignorant: the Wasp owes the preservation of her grub's provisions not + to any special qualities of her poison but to the extreme precision of her + surgery. + </p> + <p> + A last and more plausible objection is that raised by Darwin when he said + that there were no fossil remains of instincts. And, if there were, O + master, what would they teach us? Not very much more than what we learn + from the instincts of to-day. Does not the geologist make the erstwhile + carcases live anew in our minds in the light of the world as we see it? + With nothing but analogy to guide them, he describes how some saurian + lived in the jurassic age; there are no fossil remains of habits, but + nevertheless he can tell us plenty about them, things worthy of credence, + because the present teaches him the past. Let us do a little as he does. + </p> + <p> + I will suppose a precursor of the Calicurgi (The Calicurgus, or Pompilus, + is a Hunting Wasp, feeding her larvae on Spiders. Cf. "The Life and Love + of the Insect": chapter 12.—Translator's Note.) dwelling in the + prehistoric coal-forests. Her prey was some hideous Scorpion, that + first-born of the Arachnida. How did the Hymenopteron master the terrible + prey? Analogy tells us, by the methods of the present slayer of + Tarantulae. It disarmed the adversary; it paralysed the venomous sting by + a stroke administered at a point which we could determine for certain by + the animal's anatomy. Unless this was the way it happened, the assailant + must have perished, first stabbed and then devoured by the prey. There is + no getting away from it: either the precursor of the Calicurgi, that + slaughterer of Scorpions, knew her trade thoroughly, or else the + continuation of her race became impossible, even as it would be impossible + to keep up the race of the Tarantula-killer without the dagger-thrust that + paralyses the Spider's poison-fangs. The first who, greatly daring, pinked + the Scorpion of the coal-seams was already an expert fencer; the first to + come to grips with the Tarantula had an unerring knowledge of her + dangerous surgery. The least hesitation, the slightest speculation; and + they were lost. The first teacher would also have been the last, with no + disciples to take up her work and perfect it. + </p> + <p> + But fossil instincts, they insist, would show us intermediary stages, + first, second and third rungs; they would show us the gradual passing from + the casual and very incorrect attempt to the perfect practice, the fruit + of the ages; with their accidental differences, they would give us terms + of comparison wherewith to trace matters from the simple to the complex. + Never mind about that, my masters: if you want varied instincts in which + to seek the source of the complex by means of the simple, it is not + necessary to search the foliations of the coal-seams and the successive + layers of the rocks, those archives of the prehistoric world; the present + day affords to contemplation an inexhaustible treasury realizing perhaps + everything that can emerge from the limbo of possibility. In what will + soon be half a century of study, I have caught but a tiny glimpse of a + very tiny corner of the realm of instinct; and the harvest gathered + overwhelms me with its variety: I do not yet know two species of predatory + Wasps whose methods are exactly the same. + </p> + <p> + One gives a single stroke of the dagger, a second two, a third three, a + fourth nine or ten. One stabs here and the other there; and neither is + imitated by the next, who attacks elsewhere. This one injures the cephalic + centres and produces death; that one respects them and produces paralysis. + Some squeeze the cervical ganglia to obtain a temporary torpor; others + know nothing of the effects of compressing the brain. A few make the prey + disgorge, lest its honey should poison the offspring; the majority do not + resort to preventive manipulations. Here are some that first disarm the + foe, who carries poisoned daggers; yonder are others and more numerous, + who have no precautions to take before murdering the unarmed prey. In the + preliminary struggle, I know some who grab their victims by the neck, by + the rostrum, by the antennae, by the caudal threads; I know some who throw + them on their backs, some who lift them breast to breast, some who operate + on them in the vertical position, some who attack them lengthwise and + crosswise, some who climb on their backs or on their abdomens, some who + press on their backs to force out a pectoral fissure, some who open their + desperately contracted coil, using the tip of the abdomen as a wedge. And + so I could go on indefinitely: every method of fencing is employed. What + could I not also say about the egg, slung pendulum-fashion by a thread + from the ceiling, when the live provisions are wriggling underneath; laid + on a scanty mouthful, a solitary opening dish, when the dead prey requires + renewing from day to-day; entrusted to the last joint stored away, when + the victuals are paralysed; fixed at a precise spot, entailing the least + danger to the consumer and the game, when the corpulent prey has to be + devoured with a special art that warrants its freshness! + </p> + <p> + Well, how can this multitude of varied instincts teach us anything about + gradual transformation? Will the one and only dagger-thrust of the + Cerceris and the Scolia take us to the two thrusts of the Calicurgus, to + the three thrusts of the Sphex, to the manifold thrust of the Ammophila? + Yes, if we consider only numerical progression. One and one are two; two + and one are three: so run the figures. But is this what we want to know? + What has arithmetic to do with the case? Is not the whole problem + subordinate to a condition that cannot be translated into cyphers? As the + prey changes, the anatomy changes; and the surgeon always operates with a + complete understanding of his subject. The single dagger-thrust is + administered to ganglia collected into a common cluster; the manifold + thrusts are distributed over the scattered ganglia; of the two thrusts of + the Tarantula-huntress, one disarms and the other paralyses. And so with + the others: that is to say, the instinct is directed each time by the + secrets of the nervous organism. There is a perfect harmony between the + operation and the patient's anatomy. + </p> + <p> + The single stroke of the Scolia is no less wonderful than the repeated + strokes of the Ammophila. Each has her appointed game and each slays it by + a method as rational as any that our own science could invent. In the + presence of this consummate knowledge, which leaves us utterly confounded, + what a poor argument is that of 1 + 1 = 2! And what is that progress by + units to us? The universe is mirrored in a drop of water; universal logic + flashes into sight in a single sting. + </p> + <p> + Besides, push on the pitiful argument. One leads to two, two lead to + three. Granted without dispute. And then? We will accept the Scolia as the + pioneer, the foundress of the first principles of the art. The simplicity + of her method justifies our supposition. She learns her trade in some way + or other, by accident; she knows supremely well how to paralyse her + Cetonia-grub with a single dagger-thrust driven into the thorax. One day, + through some fortuitous circumstance, or rather by mistake, she takes it + into her head to strike two blows. As one is enough for the Cetonia, the + repetition was of no value unless there was a change of prey. What was the + new victim submitted to the butcher's knife? Apparently, a large Spider, + since the Tarantula and the Garden Spider call for two thrusts. And the + prentice Scolia, who used at first to sting under the throat, had the + skill, at her first attempt, to begin by disarming her adversary and then + to go quite low down, almost to the end of the thorax, to strike the vital + point. I am utterly incredulous as to her success. I see her eaten up if + her lancet swerves and hits the wrong spot. Let us look impossibility + boldly in the face and admit that she succeeds. I then see the offspring, + which have no recollection of the fortunate event save through the belly—and + then we are postulating that the digestion of the carnivorous larva leaves + a trace in the memory of the honey-sipping insect—I see the + offspring, I say, obliged to wait at long intervals for that inspired + double thrust and obliged to succeed each time under pain of death for + them and their descendants. To accept this host of impossibilities exceeds + all my faculties of belief. One leads to two, no doubt; the Ssingle blow + of the predatory Wasp will never lead to the blow twice delivered. + </p> + <p> + In order to live, we all require the conditions that enable us to live: + this is a truth worthy of the famous axioms of La Palice. (Jacques de + Chabannes, Seigneur de La Palice [circa 1470-1525]), was a French captain + killed at the battle of Pavia. His soldiers made up in his honour a + ballad, two lines of which, translated, run: + </p> + <p> + Fifteen minutes before he died, He was still alive. + </p> + <p> + (Hence the French expression, une verite de La Palice, meaning an obvious + truth.—Translator's Note.) + </p> + <p> + The predatory insects live by their talent. If they do not possess it to + perfection, their race is lost. Hidden in the murk of the past ages, the + argument based upon the non-existence of fossil instinct is no better able + than the others to withstand the light of living realities; it crumbles + under the stroke of fate; it vanishes before a La Palice platitude. + </p> + <p> + <a name="link2HCH0012" id="link2HCH0012"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 12. THE HALICTI: A PARASITE. + </h2> + <p> + Do you know the Halicti? Perhaps not. There is no great harm done: it is + quite possible to enjoy the few sweets of existence without knowing the + Halicti. Nevertheless, when questioned persistently, these humble + creatures with no history can tell us some very singular things; and their + acquaintance is not to be disdained if we would enlarge our ideas upon the + bewildering swarm of this world. Since we have nothing better to do, let + us look into the Halicti. They are worth the trouble. + </p> + <p> + How shall we recognize them? They are manufacturers of honey, generally + longer and slighter than the Bee of our hives. They constitute a numerous + group that varies greatly in size and colouring. Some there are that + exceed the dimensions of the Common Wasp; others might be compared with + the House-fly, or are even smaller. In the midst of this variety, which is + the despair of the novice, one characteristic remains invariable. Every + Halictus carries the clearly-written certificate of her guild. + </p> + <p> + Examine the last ring, at the tip of the abdomen, on the dorsal surface. + If your capture be an Halictus, there will be here a smooth and shiny + line, a narrow groove along which the sting slides up and down when the + insect is on the defensive. This slide for the unsheathed weapon denotes + some member of the Halictus tribe, without distinction of size or colour. + No elsewhere, in the sting-bearing order, is this original sort of groove + in use. It is the distinctive mark, the emblem of the family. + </p> + <p> + Three Halicti will appear before you in this biographical fragment. Two of + them are my neighbours, my familiars, who rarely fail to settle each year + in the best parts of the enclosure. They occupied the ground before I did; + and I should not dream of evicting them, persuaded as I am that they will + well repay my indulgence. Their proximity, which allows me to visit them + daily at my leisure, is a piece of good luck. Let us profit by it. + </p> + <p> + At the head of my three subjects is the Zebra Halictus (H. zebrus, + WALCK.), which is beautifully belted around her long abdomen with + alternate black and pale-russet scarves. Her slender shape, her size, + which equals that of the Common Wasp, her simple and pretty dress, combine + to make her the chief representative of the genus here. + </p> + <p> + She establishes her galleries in firm soil, where there is no danger of + landslips which would interfere with the work at nesting-time. In my + garden, the well-levelled paths, made of a mixture of tiny pebbles and red + clayey earth, suits her to perfection. Every spring she takes possession + of it, never alone, but in gangs whose number varies greatly, amounting + sometimes to as many as a hundred. In this way she founds what may be + described as small townships, each clearly marked out and distant from the + other, in which the joint possession of the site in no way entails joint + work. + </p> + <p> + Each has her home, an inviolable manor which none but the owner has the + right to enter. A sound buffeting would soon call to order any adventuress + who dared to make her way into another's dwelling. No such indiscretion is + suffered among the Halicti. Let each keep to her own place and to herself + and perfect peace will reign in this new-formed society, made up of + neighbours and not of fellow-workers. + </p> + <p> + Operations begin in April, most unobtrusively, the only sign of the + underground works being the little mounds of fresh earth. There is no + animation in the building-yards. The labourers show themselves very + seldom, so busy are they at the bottom of their pits. At moments, here and + there, the summit of a tiny mole-hill begins to totter and tumbles down + the slopes of the cone: it is a worker coming up with her armful of + rubbish and shooting it outside, without showing herself in the open. + Nothing more for the moment. + </p> + <p> + There is one precaution to be taken: the villages must be protected + against the passers-by, who might inadvertently trample them under foot. I + surround each of them with a palisade of reed-stumps. In the centre I + plant a danger-signal, a post with a paper flag. The sections of the paths + thus marked are forbidden ground; none of the household will walk upon + them. + </p> + <p> + May arrives, gay with flowers and sunshine. The navvies of April have + turned themselves into harvesters. At every moment I see them settling, + all befloured with yellow, atop of the mole-hills now turned into craters. + Let us first look into the question of the house. The arrangement of the + home will give us some useful information. A spade and a three-pronged + fork place the insect's crypts before our eyes. + </p> + <p> + A shaft as nearly vertical as possible, straight or winding according to + the exigencies of a soil rich in flinty remains, descends to a depth of + between eight and twelve inches. As it is merely a passage in which the + only thing necessary is that the Halictus should find an easy support in + coming and going, this long entrance-hall is rough and uneven. A regular + shape and a polished surface would be out of place here. These artistic + refinements are reserved for the apartments of her young. All that the + Halictus mother asks is that the passage should be easy to go up and down, + to ascend or descend in a hurry. And so she leaves it rugged. Its width is + about that of a thick lead-pencil. + </p> + <p> + Arranged one by one, horizontally and at different heights, the cells + occupy the basement of the house. They are oval cavities, three-quarters + of an inch long, dug out of the clay mass. They end in a short bottle-neck + that widens into a graceful mouth. They look like tiny vaccine-phials laid + on their sides. All of them open into the passage. + </p> + <p> + The inside of these little cells has the gloss and polish of a stucco + which our most experienced plasterers might envy. It is diapered with + faint longitudinal, diamond-shaped marks. These are the traces of the + polishing-tool that has given the last finish to the work. What can this + polisher be? None other than the tongue, that is obvious. The Halictus has + made a trowel of her tongue and licked the wall daintily and methodically + in order to polish it. + </p> + <p> + This final glazing, so exquisite in its perfection, is preceded by a + trimming-process. In the cells that are not yet stocked with provisions, + the walls are dotted with tiny dents like those in a thimble. Here we + recognize the work of the mandibles, which squeeze the clay with their + tips, compress it and purge it of any grains of sand. The result is a + milled surface whereon the polished layer will find a solid adhesive base. + This layer is obtained with a fine clay, very carefully selected by the + insect, purified, softened and then applied atom by atom, after which the + trowel of the tongue steps in, diapering and polishing, while saliva, + disgorged as needed, gives pliancy to the paste and finally dries into a + waterproof varnish. + </p> + <p> + The humidity of the subsoil, at the time of the spring showers, would + reduce the little earthen alcove to a sort of pap. The coating of saliva + is an excellent preservative against this danger. It is so delicate that + we suspect rather than see it; but its efficacy is none the less evident. + I fill a cell with water. The liquid remains in it quite well, without any + trace of infiltration. + </p> + <p> + The tiny pitcher looks as if it were varnished with galenite. The + impermeability which the potter obtains by the brutal infusion of his + mineral ingredients the Halictus achieves with the soft polisher of her + tongue moistened with saliva. Thus protected, the larva will enjoy all the + advantages of a dry berth, even in rain-soaked ground. + </p> + <p> + Should the wish seize us, it is easy to detach the waterproof film, at + least in shreds. Take the little shapeless lump in which a cell has been + excavated and put it in sufficient water to cover the bottom of it. The + whole earthy mass will soon be soaked and reduced to a mud which we are + able to sweep with the point of a hair-pencil. Let us have patience and do + our sweeping gently; and we shall be able to separate from the main body + the fragments of a sort of extremely fine satin. This transparent, + colourless material is the upholstery that keeps out the wet. The Spider's + web, if it formed a stuff and not a net, is the only thing that could be + compared with it. + </p> + <p> + The Halictus' nurseries are, as we see, structures that take much time in + the making. The insect first digs in the clayey earth a recess with an + oval curve to it. It has its mandibles for a pick-axe and its tarsi, armed + with tiny claws, for rakes. Rough though it be, this early work presents + difficulties, for the Bee has to do her excavating in a narrow gully, + where there is only just room for her to pass. + </p> + <p> + The rubbish soon becomes cumbersome. The insect collects it and then, + moving backwards, with its fore-legs closed over the load, it hoists it up + through the shaft and flings it outside, upon the mole-hill, which rises + by so much above the threshold of the burrow. Next come the dainty + finishing-touches: the milling of the wall, the application of a glaze of + better-quality clay, the assiduous polishing with the long-suffering + tongue, the waterproof coating and the jarlike mouth, a masterpiece of + pottery in which the stopping-plug will be fixed when the time comes for + locking the door of the room. And all this has to be done with + mathematical precision. + </p> + <p> + No, because of this perfection, the grubs' chambers could never be work + done casually from day to day, as the ripe eggs descend from the ovaries. + They are prepared long beforehand, during the bad weather, at the end of + March and in April, when flowers are scarce and the temperature subject to + sudden changes. This thankless period, often cold, liable to hail-storms, + is spent in making ready the home. Alone at the bottom of her shaft, which + she rarely leaves, the mother works at her children's apartments, + lavishing upon them those finishing-touches which leisure allows. They are + completed, or very nearly, when May comes with the radiant sunshine and + wealth of flowers. + </p> + <p> + We see the evidence of these long preparations in the burrows themselves, + if we inspect them before the provisions are brought. All of them show us + cells, about a dozen in number, quite finished, but still empty. To begin + by getting all the huts built is a sensible precaution: the mother will + not have to turn aside from the delicate task of harvesting and egg-laying + in order to perform rough navvy's work. + </p> + <p> + Everything is ready by May. The air is balmy; the smiling lawns are gay + with a thousand little flowers, dandelions, rock-roses, tansies and + daisies, among which the harvesting Bee rolls gleefully, covering herself + with pollen. With her crop full of honey and the brushes of her legs + befloured, the Halictus returns to her village. Flying very low, almost + level with the ground, she hesitates, with sudden turns and bewildered + movements. It seems that the weak-sighted insect finds its way with + difficulty among the cottages of its little township. + </p> + <p> + Which is its mole-hill among the many others near, all similar in + appearance? It cannot tell exactly save by the sign-board of certain + details known to itself alone. Therefore, still on the wing, tacking from + side to side, it examines the locality. The home is found at last: the + Halictus alights on the threshold of her abode and dives into it quickly. + </p> + <p> + What happens at the bottom of the pit must be the same thing that happens + in the case of the other Wild Bees. The harvester enters a cell backwards; + she first brushes herself and drops her load of pollen; then, turning + round, she disgorges the honey in her crop upon the floury mass. This + done, the unwearied one leaves the burrow and flies away, back to the + flowers. After many journeys, the stack of provisions in the cell is + sufficient. This is the moment to bake the cake. + </p> + <p> + The mother kneads her flour, mingles it sparingly with honey. The mixture + is made into a round loaf, the size of a pea. Unlike our own loaves, this + one has the crust inside and the crumb outside. The middle part of the + roll, the ration which will be consumed last, when the grub has acquired + some strength, consists of almost nothing but dry pollen. The Bee keeps + the dainties in her crop for the outside of the loaf, whence the feeble + grub-worm is to take its first mouthfuls. Here it is all soft crumb, a + delicious sandwich with plenty of honey. The little breakfast-roll is + arranged in rings regulated according to the age of the nurseling: first + the syrupy outside and at the very end the dry inside. Thus it is ordained + by the economics of the Halictus. + </p> + <p> + An egg bent like a bow is laid upon the sphere. According to the + generally-accepted rule, it now only remains to close the cabin. + Honey-gatherers—Anthophorae, Osmiae, Mason-bees and many others—usually + first collect a sufficient stock of food and then, having laid the egg, + shut up the cell, to which they need pay no more attention. The Halicti + employ a different method. The compartments, each with its round loaf and + its egg—the tenant and his provisions—are not closed up. As + they all open into the common passage of the burrow, the mother is able, + without leaving her other occupations, to inspect them daily and enquire + tenderly into the progress of her family. I imagine, without possessing + any certain proof, that from time to time she distributes additional + provisions to the grubs, for the original loaf appears to me a very frugal + ration compared with that served by the other Bees. + </p> + <p> + Certain hunting Hymenoptera, the Bembex-wasps, for instance, are + accustomed to furnish the provisions in instalments: so that the grub may + have fresh though dead game, they fill the platter each day. The Halictus + mother has not these domestic necessities, as her provisions keep more + easily; but still she might well distribute a second portion of flour to + the larvae, when their appetite attains its height. I can see nothing else + to explain the open doors of the cells during the feeding-period. + </p> + <p> + At last the grubs, close-watched and fed to repletion, have achieved the + requisite degree of fatness; they are on the eve of being transformed into + pupae. Then and not till then the cells are closed: a big clay stopper is + built by the mother into the spreading mouth of the jug. Henceforth the + maternal cares are over. The rest will come of itself. + </p> + <p> + Hitherto we have witnessed only the peaceful details of the housekeeping. + Let us go back a little and we shall be witnesses of rampant brigandage. + In May, I visit my most populous village daily, at about ten o'clock in + the morning, when the victualling-operations are in full swing. Seated on + a low chair in the sun, with my back bent and my arms upon my knees, I + watch, without moving, until dinner-time. What attracts me is a parasite, + a trumpery Gnat, the bold despoiler of the Halictus. + </p> + <p> + Has the jade a name? I trust so, without, however, caring to waste my time + in enquiries that can have no interest for the reader. Facts clearly + stated are preferable to the dry minutiae of nomenclature. Let me content + myself with giving a brief description of the culprit. She is a Dipteron, + or Fly, five millimetres long. (.195 inch.—Translator's Note.) Eyes, + dark-red; face, white. Corselet, pearl-grey, with five rows of fine black + dots, which are the roots of stiff bristles pointing backwards. Greyish + belly, pale below. Black legs. + </p> + <p> + She abounds in the colony under observation. Crouching in the sun, near a + burrow, she waits. As soon as the Halictus arrives from her harvesting, + her legs yellow with pollen, the Gnat darts forth and pursues her, keeping + behind her in all the turns of her oscillating flight. At last, the Bee + suddenly dives indoors. No less suddenly the other settles on the + mole-hill, quite close to the entrance. Motionless, with her head turned + towards the door of the house, she waits for the Bee to finish her + business. The latter reappears at last and, for a few seconds, stands on + the threshold, with her head and thorax outside the hole. The Gnat, on her + side, does not stir. + </p> + <p> + Often, they are face to face, separated by a space no wider than a + finger's breadth. Neither of them shows the least excitement. The Halictus—judging, + at least, by her tranquillity—takes no notice of the parasite lying + in wait for her; the parasite, on the other hand, displays no fear of + being punished for her audacity. She remains imperturbable, she, the + dwarf, in the presence of the colossus who could crush her with one blow. + </p> + <p> + In vain I watch anxiously for some sign of apprehension on either side: + nothing in the Halictus points to a knowledge of the danger run by her + family; nor does the Gnat betray any dread of swift retribution. Plunderer + and plundered stare at each other for a moment; and that is all. + </p> + <p> + If she liked, the amiable giantess could rip up with her claw the tiny + bandit who ruins her home; she could crunch her with her mandibles, run + her through with her stiletto. She does nothing of the sort, but leaves + the robber in peace, to sit quite close, motionless, with her red eyes + fixed on the threshold of the house. Why this fatuous clemency? + </p> + <p> + The Bee flies off. Forthwith, the Gnat walks in, with no more ceremony + than if she were entering her own place. She now chooses among the + victualled cells at her ease, for they are all open, as I have said; she + leisurely deposits her eggs. No one will disturb her until the Bee's + return. To flour one's legs with pollen, to distend one's crop with syrup + is a task that takes long a-doing; and the intruder, therefore, has time + and to spare wherein to commit her felony. Moreover, her chronometer is + well-regulated and gives the exact measure of the Bee's length of absence. + When the Halictus comes back from the fields, the Gnat has decamped. In + some favourable spot, not far from the burrow, she awaits the opportunity + for a fresh misdeed. + </p> + <p> + What would happen if a parasite were surprised at her work by the Bee? + Nothing serious. I see them, greatly daring, follow the Halictus right + into the cave and remain there for some time while the mixture of pollen + and honey is being prepared. Unable to make use of the paste so long as + the harvester is kneading it, they go back to the open air and wait on the + threshold for the Bee to come out. They return to the sunlight, calmly, + with unhurried steps: a clear proof that nothing untoward has occurred in + the depths where the Halictus works. + </p> + <p> + A tap on the Gnat's neck, if she become too enterprising in the + neighbourhood of the cake: that is all that the lady of the house seems to + allow herself, to drive away the intruder. There is no serious affray + between the robber and the robbed. This is apparent from the + self-possessed manner and undamaged condition of the dwarf who returns + from visiting the giantess engaged down in the burrow. + </p> + <p> + The Bee, when she comes home, whether laden with provisions or not, + hesitates, as I have said, for a while; in a series of rapid zigzags, she + moves backwards, forwards and from side to side, at a short distance from + the ground. This intricate flight at first suggests the idea that she is + trying to lead her persecutress astray by means of an inextricable tangle + of marches and countermarches. That would certainly be a prudent move on + the Bee's part; but so much wisdom appears to be denied her. + </p> + <p> + It is not the enemy that is disturbing her, but rather the difficulty of + finding her own house amid the confusion of the mole-hills, encroaching + one upon the other, and all the alleys of the little township, which, + owing to landslips of fresh rubbish, alter in appearance from one day to + the next. Her hesitation is manifest, for she often blunders and alights + at the entrance to a burrow that is not hers. The mistake is at once + perceived from the slight indications of the doorway. + </p> + <p> + The search is resumed with the same see-sawing flights, mingled with + sudden excursions to a distance. At last, the burrow is recognized. The + Halictus dives into it with a rush; but, however prompt her disappearance + underground, the Gnat is there, perched on the threshold with her eyes + turned to the entrance, waiting for the Bee to come out, so that she may + visit the honey-jars in her turn. + </p> + <p> + When the owner of the house ascends, the other draws back a little, just + enough to leave a free passage and no more. Why should she put herself + out? the meeting is so peaceful that, short of further information, one + would not suspect that a destroyer and destroyed were face to face. Far + from being intimidated by the sudden arrival of the Halictus, the Gnat + pays hardly any attention; and, in the same way, the Halictus takes no + notice of her persecutress, unless the bandit pursue her and worry her on + the wing. Then, with a sudden bend, the Bee makes off. + </p> + <p> + Even so do Philanthus apivorus (The Bee-hunting Wasp. Cf. "Social Life in + the Insect World": chapter 13.—Translator's Note.) and the other + game-hunters behave when the Tachina is at their heels seeking the chance + to lay her egg on the morsel about to be stored away. Without jostling the + parasite which they find hanging around the burrow, they go indoors quite + peaceably; but, on the wing, perceiving her after them, they dart off + wildly. The Tachina, however, dares not go down to the cells where the + huntress stacks her provisions; she prudently waits at the door for the + Philanthus to arrive. The crime, the laying of the egg, is committed at + the very moment when the victim is about to vanish underground. + </p> + <p> + The troubles of the parasite of the Halictus are of quite another kind. + The homing Bee has her honey in her crop and her pollen on her + leg-brushes: the first is inaccessible to the thief; the second is powdery + and would give no resting-place to the egg. Besides, there is not enough + of it yet: to collect the wherewithal for that round loaf of hers, the Bee + will have to make repeated journeys. When the necessary amount is + obtained, she will knead it with the tip of her mandibles and shape it + with her feet into a little ball. The Gnat's egg, were it present among + the materials, would certainly be in danger during this manipulation. + </p> + <p> + The alien egg, therefore, must be laid on the finished bread; and, as the + preparation takes place underground, the parasite is needs obliged to go + down to the Halictus. With inconceivable daring, she does go down, even + when the Bee is there. Whether through cowardice or silly indulgence, the + dispossessed insect lets the other have its way. + </p> + <p> + The object of the Gnat, with her tenacious lying-in-wait and her reckless + burglaries, is not to feed herself at the harvester's expense: she could + get her living out of the flowers with much less trouble than her thieving + trade involves. The most, I think, that she can allow herself to do in the + Halictus' cellars is to take one morsel just to ascertain the quality of + the victuals. Her great, her sole business is to settle her family. The + stolen goods are not for herself, but for her offspring. + </p> + <p> + Let us dig up the pollen-loaves. We shall find them most often crumbled + with no regard to economy, simply frittered away. We shall see two or + three maggots, with pointed mouths, moving in the yellow flour scattered + over the floor of the cell. These are the Gnat's progeny. With them we + sometimes find the lawful owner, the grub-worm of the Halictus, but + stunted and emaciated with fasting. His gluttonous companions, without + otherwise molesting him, deprive him of the best of everything. The + wretched starveling dwindles, shrivels up and soon disappears from view. + His corpse, a mere atom, blended with the remaining provisions, supplies + the maggots with one mouthful the more. + </p> + <p> + And what does the Halictus mother do in this disaster? She is free to + visit her grubs at any moment; she has but to put her head into the + passage of the house: she cannot fail to be apprised of their distress. + The squandered loaf, the swarming mass of vermin tell their own tale. Why + does she not take the intruders by the skin of the abdomen? To grind them + to powder with her mandibles, to fling them out of doors were the business + of a second. And the foolish creature never thinks of it, leaves the + ravagers in peace! + </p> + <p> + She does worse. When the time of the nymphosis comes, the Halictus mother + goes to the cells rifled by the parasite and closes them with an earthen + plug as carefully as she does the rest. This final barricade, an excellent + precaution when the cot is occupied by an Halictus in course of + metamorphosis, becomes the height of absurdity when the Gnat has passed + that way. Instinct does not hesitate in the face of this ineptitude: it + seals up emptiness. I say, emptiness, because the crafty maggot hastens to + decamp the instant that the victuals are consumed, as though it foresaw an + insuperable obstacle for the coming Fly: it quits the cell before the Bee + closes it. + </p> + <p> + To rascally guile the parasite adds prudence. All, until there is none of + them left, abandon the clay homes which would be their undoing once the + entrance was plugged up. The earthen niche, so grateful to the tender + skin, thanks to its polished coating, so free from humidity, thanks to its + waterproof glaze, ought, one would think, to make an excellent + waiting-place. The maggots will have none of it. Lest they should find + themselves walled in when they become frail Gnats, they go away and + disperse in the neighbourhood of the ascending shaft. + </p> + <p> + My digging operations, in fact, always reveal the pupae outside the cells, + never inside. I find them enshrined, one by one, in the body of the clayey + earth, in a narrow recess which the emigrant worm has contrived to make + for itself. Next spring, when the hour comes for leaving, the adult insect + has but to creep through the rubbish, which is easy work. + </p> + <p> + Another and no less imperative reason compels this change of abode on the + parasite's part. In July, a second generation of the Halictus is + procreated. The Gnat, reduced on her side to a single brood, remains in + the pupa state and awaits the spring of the following year before + effecting her transformation. The honey-gather resumes her work in her + native village; she avails herself of the pits and cells constructed in + the spring, saving no little time thereby. The whole elaborate structure + has remained in good condition. It needs but a few repairs to make the old + house habitable. + </p> + <p> + Now what would happen if the Bee, so scrupulous in matters of cleanliness, + were to find a pupa in the cell which she is sweeping? She would treat the + cumbersome object as she would a piece of old plaster. It would be no more + to her than any other refuse, a bit of gravel, which, seized with the + mandibles, crushed perhaps, would be sent to join the rubbish-heap + outside. Once removed from the soil and exposed to the inclemencies of the + weather, the pupa would inevitably perish. + </p> + <p> + I admire this intelligent foresight of the maggot, which forgoes the + comfort of the moment for the security of the future. Two dangers threaten + it: to be immured in a casket whence the Fly can never issue; or else to + die out of doors, in the unkindly air, when the Bee sweeps out the + restored cells. To avoid this twofold peril, it decamps before the door is + closed, before the July Halictus sets her house in order. + </p> + <p> + Let us now see what comes of the parasite's intrusion. In the course of + June, when peace is established in the Halictus' home, I dig up my largest + village, comprising some fifty burrows in all. None of the sorrows of this + underworld shall escape me. There are four of us engaged in sifting the + excavated earth through our fingers. What one has examined another takes + up and examines; and then another and another yet. The returns are + heartrending. We do not succeed in finding one single nymph of the + Halictus. The whole of the populous city has perished; and its place has + been taken by the Gnat. There is a glut of that individual's pupae. I + collect them in order to trace their evolution. + </p> + <p> + The year runs its course; and the little russet kegs, into which the + original maggots have hardened and contracted, remain stationary. They are + seeds endowed with latent life. The heats of July do not rouse them from + their torpor. In that month, the period of the second generation of the + Halictus, there is a sort of truce of God: the parasite rests and the Bee + works in peace. If hostilities were to be resumed straight away, as + murderous in summer as they were in spring, the progeny of the Halictus, + too cruelly smitten, might possibly disappear altogether. This lull + readjusts the balance. + </p> + <p> + In April, when the Zebra Halictus, in search of a good place for her + burrows, roams up and down the garden paths with her oscillating flight, + the parasite, on its side, hastens to hatch. Oh, the precise and terrible + agreement between those two calendars, the calendar of the persecutor and + the persecuted! At the very moment when the Bee comes out, here is the + Gnat: she is ready to begin her deadly starving-process all over again. + </p> + <p> + Were this an isolated case, one's mind would not dwell upon it: an + Halictus more or less in the world makes little difference in the general + balance. But, alas, brigandage in all its forms is the rule in the eternal + conflict of living things! From the lowest to the highest, every producer + is exploited by the unproductive. Man himself, whose exceptional rank + ought to raise him above such baseness, excels in this ravening lust. He + says to himself that business means getting hold of other people's cash, + even as the Gnat says to herself that business means getting hold of the + Halictus' honey. And, to play the brigand to better purpose, he invents + war, the art of killing wholesale and of doing with glory that which, when + done on a smaller scale, leads to the gallows. + </p> + <p> + Shall we never behold the realization of that sublime vision which is sung + on Sundays in the smallest village-church: Gloria in excelsis Deo, et in + terra pax hominibus bonae voluntatis! If war affected humanity alone, + perhaps the future would have peace in store for us, seeing that generous + minds are working for it with might and main; but the scourge also rages + among the lower animals, which in their obstinate way, will never listen + to reason. Once the evil is laid down as a general condition, it perhaps + becomes incurable. Life in the future, it is to be feared, will be what it + is to-day, a perpetual massacre. + </p> + <p> + Whereupon, by a desperate effort of the imagination, one pictures to + oneself a giant capable of juggling with the planets. He is irresistible + strength; he is also law and justice. He knows of our battles, our + butcheries, our farm-burnings, our town-burnings, our brutal triumphs; he + knows our explosives, our shells, our torpedo-boats, our ironclads and all + our cunning engines of destruction; he knows as well the appalling extent + of the appetites among all creatures, down to the very lowest. Well, if + that just and mighty one held the earth under his thumb, would he hesitate + whether he ought to crush it? + </p> + <p> + He would not hesitate...He would let things take their course. He would + say to himself: + </p> + <p> + 'The old belief is right; the earth is a rotten apple, gnawed by the + vermin of evil. It is a first crude attempt, a step towards a kindlier + destiny. Let it be: order and justice are waiting at the end.' + </p> + <p> + <a name="link2HCH0013" id="link2HCH0013"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 13. THE HALICTI: THE PORTRESS. + </h2> + <p> + Leaving our village is no very serious matter when we are children. We + even look on it as a sort of holiday. We are going to see something new, + those magic pictures of our dreams. With age come regrets; and the close + of life is spent in stirring up old memories. Then the beloved village + reappears, in the biograph of the mind, embellished, transfigured by the + glow of those first impressions; and the mental image, superior to the + reality, stands out in amazingly clear relief. The past, the far-off past, + was only yesterday; we see it, we touch it. + </p> + <p> + For my part, after three-quarters of a century, I could walk with my eyes + closed straight to the flat stone where I first heard the soft chiming + note of the Midwife Toad; yes, I should find it to a certainty, if time, + which devastates all things, even the homes of Toads, has not moved it or + perhaps left it in ruins. + </p> + <p> + I see, on the margin of the brook, the exact position of the alder-trees + whose tangled roots, deep under the water, were a refuge for the Crayfish. + I should say: + </p> + <p> + 'It is just at the foot of that tree that I had the unutterable bliss of + catching a beauty. She had horns so long...and enormous claws, full of + meat, for I got her just at the right time.' + </p> + <p> + I should go without faltering to the ash under whose shade my heart beat + so loudly one sunny spring morning. I had caught sight of a sort of white, + cottony ball among the branches. Peeping from the depths of the wadding + was an anxious little head with a red hood to it. O what unparalleled + luck! It was a Goldfinch, sitting on her eggs. + </p> + <p> + Compared with a find like this, lesser events do not count. Let us leave + them. In any case, they pale before the memory of the paternal garden, a + tiny hanging garden of some thirty paces by ten, situated right at the top + of the village. The only spot that overlooks it is a little esplanade on + which stands the old castle (The Chateau de Saint-Leons standing just + outside and above the village of Saint-Leons, where the author was born in + 1823. Cf. "The Life of the Fly": chapters 6 and 7.—Translator's + Note.) with the four turrets that have now become dovecotes. A steep path + takes you up to this open space. From my house on, it is more like a + precipice than a slope. Gardens buttressed by walls are staged in terraces + on the sides of the funnel-shaped valley. Ours is the highest; it is also + the smallest. + </p> + <p> + There are no trees. Even a solitary apple-tree would crowd it. There is a + patch of cabbages, with a border of sorrel, a patch of turnips and another + of lettuces. That is all we have in the way of garden-stuff; there is no + room for more. Against the upper supporting-wall, facing due south, is a + vine-arbour which, at intervals, when the sun is generous, provides half a + basketful of white muscatel grapes. These are a luxury of our own, greatly + envied by the neighbours, for the vine is unknown outside this corner, the + warmest in the village. + </p> + <p> + A hedge of currant-bushes, the only safeguard against a terrible fall, + forms a parapet above the next terrace. When our parents' watchful eyes + are off us, we lie flat on our stomachs, my brother and I, and look into + the abyss at the foot of the wall bulging under the thrust of the land. It + is the garden of monsieur le notaire. + </p> + <p> + There are beds with box-borders in that garden; there are pear-trees + reputed to give pears, real pears, more or less good to eat when they have + ripened on the straw all through the late autumn. In our imagination, it + is a spot of perpetual delight, a paradise, but a paradise seen the wrong + way up: instead of contemplating it from below, we gaze at it from above. + How happy they must be with so much space and all those pears! + </p> + <p> + We look at the hives, around which the hovering Bees make a sort of russet + smoke. They stand under the shelter of a great hazel. The tree has sprung + up all of itself in a fissure of the wall, almost on the level of our + currant-bushes. While it spreads its mighty branches over the notary's + hives, its roots, at least, are on our land. It belongs to us. The trouble + is to gather the nuts. + </p> + <p> + I creep along astride the strong branches projecting horizontally into + space. If I slip or if the support breaks, I shall come to grief in the + midst of the angry Bees. I do not slip and the support does not break. + With the bent switch which my brother hands me, I bring the finest + clusters within my reach. I soon fill my pockets. Moving backwards, still + straddling my branch, I recover terra firma. O wondrous days of litheness + and assurance, when, for a few filberts, on a perilous perch we braved the + abyss! + </p> + <p> + Enough. These reminiscences, so dear to my dreams, do not interest the + reader. Why stir up more of them? I am content to have brought this fact + into prominence: the first glimmers of light penetrating into the dark + chambers of the mind leave an indelible impression, which the years make + fresher instead of dimmer. + </p> + <p> + Obscured by everyday worries, the present is much less familiar to us, in + its petty details, than the past, with childhood's glow upon it. I see + plainly in my memory what my prentice eyes saw; and I should never succeed + in reproducing with the same accuracy what I saw last week. I know my + village thoroughly, though I quitted it so long ago; and I know hardly + anything of the towns to which the vicissitudes of life have brought me. + An exquisitely sweet link binds us to our native soil; we are like the + plant that has to be torn away from the spot where it put out its first + roots. Poor though it be, I should love to see my own village again; I + should like to leave my bones there. + </p> + <p> + Does the insect in its turn receive a lasting impression of its earliest + visions? Has it pleasant memories of its first surroundings? We will not + speak of the majority, a world of wandering gipsies who establish + themselves anywhere provided that certain conditions be fulfilled; but the + others, the settlers, living in groups: do they recall their native + village? Have they, like ourselves, a special affection for the place + which saw their birth? + </p> + <p> + Yes, indeed they have: they remember, they recognize the maternal abode, + they come back to it, they restore it, they colonize it anew. Among many + other instances, let us quote that of the Zebra Halictus. She will show us + a splendid example of love for one's birthplace translating itself into + deeds. + </p> + <p> + The Halictus' spring family acquire the adult form in a couple of months + or so; they leave the cells about the end of June. What goes on inside + these neophytes as they cross the threshold of the burrow for the first + time? Something, apparently, that may be compared with our own impressions + of childhood. An exact and indelible image is stamped on their virgin + memories. Despite the years, I still see the stone whence came the + resonant notes of the little Toads, the parapet of currant-bushes, the + notary's garden of Eden. These trifles make the best part of my life. The + Halictus sees in the same way the blade of grass whereon she rested in her + first flight, the bit of gravel which her claw touched in her first climb + to the top of the shaft. She knows her native abode by heart just as I + know my village. The locality has become familiar to her in one glad, + sunny morning. + </p> + <p> + She flies off, seeks refreshment on the flowers near at hand and visits + the fields where the coming harvests will be gathered. The distance does + not lead her astray, so faithful are her impressions of her first trip; + she finds the encampment of her tribe; among the burrows of the village, + so numerous and so closely resembling one another, she knows her own. It + is the house where she was born, the beloved house with its unforgettable + memories. + </p> + <p> + But, on returning home, the Halictus is not the only mistress of the + house. The dwelling dug by the solitary Bee in early spring remains, when + summer comes, the joint inheritance of the members of the family. There + are ten cells, or thereabouts, underground. Now from these cells there + have issued none but females. This is the rule among the three species of + Halicti that concern us now and probably also among many others, if not + all. They have two generations in each year. The spring one consists of + females only; the summer one comprises both males and females, in almost + equal numbers. We shall return to this curious subject in our next + chapter. + </p> + <p> + The household, therefore, if not reduced by accidents, above all if not + starved by the usurping Gnat, would consist of half-a-score of sisters, + none but sisters, all equally industrious and all capable of procreating + without a nuptial partner. On the other hand, the maternal dwelling is no + hovel; far from it: the entrance-gallery, the principal room of the house, + will serve quite well, after a few odds and ends of refuse have been swept + away. This will be so much gained in time, ever precious to the Bee. The + cells at the bottom, the clay cabins, are also nearly intact. To make use + of them, it will be enough for the Halictus to polish up the stucco with + her tongue. + </p> + <p> + Well, which of the survivors, all equally entitled to the succession, will + inherit the house? There are six of them, seven, or more, according to the + chances of mortality. To whose share will the maternal dwelling fall? + </p> + <p> + There is no quarrel between the interested parties. The mansion is + recognized as common property without dispute. The sisters come and go + peacefully through the same door, attend to their business, pass and let + the others pass. Down at the bottom of the pit, each has her little + demesne, her group of cells dug at the cost of fresh toil, when the old + ones, now insufficient in number, are occupied. In these recesses, which + are private estates, each mother works by herself, jealous of her property + and of her privacy. Every elsewhere, traffic is free to all. + </p> + <p> + The exits and entrances in the working fortress provide a spectacle of the + highest interest. A harvester arrives from the fields, the feather-brushes + of her legs powdered with pollen. If the door be open, the Bee at once + dives underground. To tarry on the threshold would mean waste of time; and + the business is urgent. Sometimes, several appear upon the scene at almost + the same moment. The passage is too narrow for two, especially when they + have to avoid any untimely contact that would make the floury burden fall + to the floor. The nearest to the opening enters quickly. The others, drawn + up on the threshold in order of their arrival, respectful of one another's + rights, await their turn. As soon as the first disappears, the second + follows after her and is herself swiftly followed by the third and then + the others, one by one. + </p> + <p> + Sometimes, again, there is a meeting between a Bee about to come out and a + Bee about to go in. Then the latter draws back a little and makes way for + the former. The politeness is reciprocal. I see some who, when on the + point of emerging from the pit, go down again and leave the passage free + for the one who has just arrived. Thanks to this mutual spirit of + accommodation, the business of the house proceeds without impediment. + </p> + <p> + Let us keep our eyes open. There is something better than the + well-preserved order of the entrances. When an Halictus appears, returning + from her round of the flowers, we see a sort of trap-door, which closed + the house, suddenly fall and give a free passage. As soon as the new + arrival has entered, the trap rises back into its place, almost level with + the ground, and closes the entrance anew. The same thing happens when the + insects go out. At a request from within, the trap descends, the door + opens and the Bee flies away. The outlet is closed forthwith. + </p> + <p> + What can this valve be which, descending or ascending in the cylinder of + the pit, after the fashion of a piston, opens and closes the house at each + departure and at each arrival? It is an Halictus, who has become the + portress of the establishment. With her large head, she makes an + impassable barrier at the top of the entrance-hall. If any one belonging + to the house wants to go in or out, she 'pulls the cord,' that is to say, + she withdraws to a spot where the gallery becomes wider and leaves room + for two. The other passes. She then at once returns to the orifice and + blocks it with the top of her head. Motionless, ever on the look-out, she + does not leave her post save to drive away importunate visitors. + </p> + <p> + Let us profit by her brief appearances outside to take a look at her. We + recognize in her an Halictus similar to the others, which are now busy + harvesting; but the top of her head is bald and her dress is dingy and + thread-bare. All the nap is gone; and one can hardly make out the handsome + stripes of red and brown which she used to have. These tattered, work-worn + garments make things clear to us. + </p> + <p> + This Bee who mounts guard and performs the office of a portress at the + entrance to the burrow is older than the others. She is the foundress of + the establishment, the mother of the actual workers, the grandmother of + the present grubs. In the springtime of her life, three months ago, she + wore herself out in solitary labours. Now that her ovaries are dried up, + she takes a well-earned rest. No, rest is hardly the word. She still + works, she assists the household to the best of her power. Incapable of + being a mother for a second time, she becomes a portress, opens the door + to the members of her family and makes strangers keep their distance. + </p> + <p> + The suspicious Kid (In La Fontaine's fable, "Le Loup, la Chevre et le + Chevreau."—Translator's Note.), looking through the chink, said to + the Wolf: + </p> + <p> + 'Show me a white foot, or I shan't open the door.' + </p> + <p> + No less suspicious, the grandmother says to each comer: + </p> + <p> + 'Show me the yellow foot of an Halictus, or you won't be let in.' + </p> + <p> + None is admitted to the dwelling unless she be recognized as a member of + the family. + </p> + <p> + See for yourselves. Near the burrow passes an Ant, an unscrupulous + adventuress, who would not be sorry to know the meaning of the honeyed + fragrance that rises from the bottom of the cellar. + </p> + <p> + "Be off, or you'll catch it!' says the portress, wagging her neck. + </p> + <p> + As a rule the threat suffices. The Ant decamps. Should she insist, the + watcher leaves her sentry-box, flings herself upon the saucy jade, buffets + her and drives her away. The moment the punishment has been administered, + she returns to her post. + </p> + <p> + Next comes the turn of a Leaf-cutter (Megachile albocincta, PEREZ), which, + unskilled in the art of burrowing, utilizes, after the manner of her kin, + the old galleries dug by others. Those of the Zebra Halictus suit her very + well, when the terrible Gnat has left them vacant for lack of heirs. + Seeking for a home wherein to stack her robinia-leaf honey-pots, she often + makes a flying inspection of my colonies of Halicti. A burrow seems to + take her fancy; but, before she sets foot on earth, her buzzing is noticed + by the sentry, who suddenly darts out and makes a few gestures on the + threshold of her door. That is all. The Leaf-cutter has understood. She + moves on. + </p> + <p> + Sometimes, the Megachile has time to alight and insert her head into the + mouth of the pit. In a moment, the portress is there, comes a little + higher and bars the way. Follows a not very serious contest. The stranger + quickly recognizes the rights of the first occupant and, without + insisting, goes to seek an abode elsewhere. + </p> + <p> + An accomplished marauder (Caelioxys caudata, SPIN.), a parasite of the + Megachile, receives a sound drubbing under my eyes. She thought, the + feather-brain, that she was entering the Leaf-Cutter's establishment! She + soon finds out her mistake; she meets the door-keeping Halictus, who + administers a sharp correction. She makes off at full speed. And so with + the others which, through inadvertence or ambition, seek to enter the + burrow. + </p> + <p> + The same intolerance exists among the different grandmothers. About the + middle of July, when the animation of the colony is at its height, two + sets of Halicti are easily distinguishable: the young mothers and the old. + The former, much more numerous, brisk of movement and smartly arrayed, + come and go unceasingly from the burrows to the fields and from the fields + to the burrows. The latter, faded and dispirited, wander idly from hole to + hole. They look as though they had lost their way and were incapable of + finding their homes. Who are these vagabonds? I see in them afflicted ones + bereft of a family through the act of the odious Gnat. Many burrows have + been altogether exterminated. At the awakening of summer, the mother found + herself alone. She left her empty house and went off in search of a + dwelling where there were cradles to defend, a guard to mount. But those + fortunate nests already have their overseer, the foundress, who, jealous + of her rights, gives her unemployed neighbour a cold reception. One sentry + is enough; two would merely block the narrow guard-room. + </p> + <p> + I am privileged at times to witness a fight between two grandmothers. When + the tramp in quest of employment appears outside the door, the lawful + occupant does not move from her post, does not withdraw into the passage, + as she would before an Halictus returning from the fields. Far from making + way, she threatens the intruder with her feet and mandibles. The other + retaliates and tries to force her way in notwithstanding. Blows are + exchanged. The fray ends by the defeat of the stranger, who goes off to + pick a quarrel elsewhere. + </p> + <p> + These little scenes afford us a glimpse of certain details of the highest + interest in the habits of the Zebra Halictus. The mother who builds her + nest in the spring no longer leaves her home, once her works are finished. + Shut up at the bottom of the burrow, busied with the thousand cares of + housekeeping, or else drowsing, she waits for her daughters to come out. + When, in the summer heats, the life of the village recommences, having + nought to do outside as a harvester, she stands sentry at the entrance to + the hall, so as to let none in save the workers of the home, her own + daughters. She wards off evilly-disposed visitors. None can enter without + the door-keeper's consent. + </p> + <p> + There is nothing to tell us that the watcher ever deserts her post. Not + once do I see her leave her house to go and seek some refreshment from the + flowers. Her age and her sedentary occupation, which involves no great + fatigue, perhaps relieve her of the need of nourishment. Perhaps, also, + the young ones returning from their plundering may from time to time + disgorge a drop of the contents of their crops for her benefit. Fed or + unfed, the old one no longer goes out. + </p> + <p> + But what she does need is the joys of an active family. Many are deprived + of these. The Gnat's burglary has destroyed the busy household. The + sorely-tried Bees abandon the deserted burrow. It is they who, ragged and + careworn, wander through the village. When they move, their flight is only + a short one; more often they remain motionless. It is they who, soured in + their tempers, attack their fellows and seek to dislodge them. They grow + rarer and more languid from day to day; then they disappear for good. What + has become of them? The little Grey Lizard had his eye on them: they are + easily snapped up. + </p> + <p> + Those settled in their own demesne, those who guard the honey-factory + wherein their daughters, the heiresses of the maternal establishment, are + at work, display wonderful vigilance. The more I see of them, the more I + admire them. In the cool hours of the early morning, when the pollen-flour + is not sufficiently ripened by the sun and while the harvesters are still + indoors, I see them at their posts, at the top of the gallery. Here, + motionless, their heads flush with the earth, they bar the door to all + invaders. If I look at them closely, they retreat a little and, in the + shadow, await the indiscreet observer's departure. + </p> + <p> + I return when the harvesting is in full swing, between eight o'clock and + twelve. There is now, as the Halicti go in or out, a succession of prompt + withdrawals to open the door and of ascents to close it. The portress is + in the full exercise of her functions. + </p> + <p> + In the afternoon, the heat is too great and the workers do not go to the + fields. Retiring to the bottom of the house, they varnish the new cells, + they make the round loaf that is to receive the egg. The grandmother is + still upstairs, stopping the door with her bald head. For her, there is no + siesta during the stifling hours: the safety of the household requires her + to forgo it. + </p> + <p> + I come back again at nightfall, or even later. By the light of a lantern, + I again behold the overseer, as zealous and assiduous as in the day-time. + The others are resting, but not she, for fear, apparently, of nocturnal + dangers known to herself alone. Does she nevertheless end by descending to + the quiet of the floor below? It seems probable, so essential must rest + be, after the fatigue of such a vigil! + </p> + <p> + It is evident that, guarded in this manner, the burrow is exempt from + calamities similar to those which, too often, depopulate it in May. Let + the Gnat come now, if she dare, to steal the Halictus' loaves! Let her lie + in wait as long as she will! Neither her audacity nor her slyness will + make her escape the lynx eyes of the sentinel, who will put her to flight + with a threatening gesture or, if she persist, crush her with her nippers. + She will not come; and we know the reason: until spring returns, she is + underground in the pupa state. + </p> + <p> + But, in her absence, there is no lack, among the Fly rabble, of other + batteners on the toil of their fellow insects. Whatever the job, whatever + the plunder, you will find parasites there. And yet, for all my daily + visits, I never catch one of these in the neighbourhood of the summer + burrows. How cleverly the rascals ply their trade! How well aware are they + of the guard who keeps watch at the Halictus' door! There is no foul deed + possible nowadays; and the result is that no Fly puts in an appearance and + the tribulations of last spring are not repeated. + </p> + <p> + The grandmother who, dispensed by age from maternal bothers, mounts guard + at the entrance of the home and watches over the safety of the family, + tells us that in the genesis of the instincts sudden births occur; she + shows us the existence of a spontaneous aptitude which nothing, either in + her own past conduct or in the actions of her daughters, could have led us + to suspect. Timorous in her prime, in the month of May, when she lived + alone in the burrow of her making, she has become gifted, in her decline, + with a superb contempt of danger and dares in her impotence what she never + dared do in her strength. + </p> + <p> + Formerly, when her tyrant, the Gnat, entered the house in her presence, + or, more often, stood face to face with her at the entrance, the silly Bee + did not stir, did not even threaten the red-eyed bandit, the dwarf whose + doom she could so easily have sealed. Was it terror on her part? No, for + she attended to her duties with her usual punctiliousness; no, for the + strong do not allow themselves to be thus paralysed by the weak. It was + ignorance of the danger, it was sheer fecklessness. + </p> + <p> + And behold, to-day, the ignoramus of three months ago knows the peril, + knows it well, without serving any apprenticeship. Every stranger who + appears is kept at a distance, without distinction of size or race. If the + threatening gesture be not enough, the keeper sallies forth and flings + herself upon the persistent one. Cowardice has developed into courage. + </p> + <p> + How has this change been brought about? I should like to picture the + Halictus gaining wisdom from the misfortunes of the spring and capable + thenceforth of looking out for danger; I would gladly credit her with + having learnt in the stern school of experience the advantages of a + patrol. I must give up the idea. If, by dint of gradual little acts of + progress, the Bee has achieved the glorious invention of a janitress, how + comes it that the fear of thieves is intermittent? It is true that, being + by herself in May, she cannot stand permanently at her door: the business + of the house takes precedence of everything else. But she ought, at any + rate as soon as her offspring are victimized, to know the parasite and + give chase when, at every moment, she finds her almost under her feet and + even in her house. Yet she pays no attention to her. + </p> + <p> + The bitter experience of her ancestors, therefore, has bequeathed nothing + to her of a nature to alter her placid character; nor have her own + tribulations aught to do with the sudden awakening of her vigilance in + July. Like ourselves, animals have their joys and their sorrows. They + eagerly make the most of the former; they fret but little about the + latter, which, when all is said, is the best way of achieving a purely + animal enjoyment of life. To mitigate these troubles and protect the + progeny there is the inspiration of instinct, which is able without the + counsels of experience to give the Halicti a portress. + </p> + <p> + When the victualling is finished, when the Halicti no longer sally forth + on harvesting intent nor return all befloured with their spoils, the old + Bee is still at her post, vigilant as ever. The final preparations for the + brood are made below; the cells are closed. The door will be kept until + everything is finished. Then grandmother and mothers leave the house. + Exhausted by the performance of their duty, they go, somewhere or other, + to die. + </p> + <p> + In September appears the second generation, comprising both males and + females. I find both sexes wassailing on the flowers, especially the + Compositae, the centauries and thistles. They are not harvesting now: they + are refreshing themselves, holding high holiday, teasing one another. It + is the wedding-time. Yet another fortnight and the males will disappear, + henceforth useless. The part of the idlers is played. Only the industrious + ones remain, the impregnated females, who go through the winter and set to + work in April. + </p> + <p> + I do not know their exact haunt during the inclement season. I expected + them to return to their native burrow, an excellent dwelling for the + winter, one would think. Excavations made in January showed me my mistake. + The old homes are empty, are falling to pieces owing to the prolonged + effect of the rains. The Zebra Halictus has something better than these + muddy hovels: she has snug corners in the stone-heaps, hiding-places in + the sunny walls and many other convenient habitations. And so the natives + of a village become scattered far and wide. + </p> + <p> + In April, the scattered ones reassemble from all directions. On the + well-flattened garden-paths a choice is made of the site for their common + labours. Operations soon begin. Close to the first who bores her shaft + there is soon a second one busy with hers; a third arrives, followed by + another and others yet, until the little mounds often touch one another, + while at times they number as many as fifty on a surface of less than a + square yard. + </p> + <p> + One would be inclined, at first sight, to say that these groups are + accounted for by the insect's recollection of its birthplace, by the fact + that the villagers, after dispersing during the winter, return to their + hamlet. But it is not thus that things happen: the Halictus scorns to-day + the place that once suited her. I never see her occupy the same patch of + ground for two years in succession. Each spring she needs new quarters. + And there are plenty of them. + </p> + <p> + Can this mustering of the Halicti be due to a wish to resume the old + intercourse with their friends and relations? Do the natives of the same + burrow, of the same hamlet, recognize one another? Are they inclined to do + their work among themselves rather than in the company of strangers? There + is nothing to prove it, nor is there anything to disprove it. Either for + this reason or for others, the Halictus likes to keep with her neighbours. + </p> + <p> + This propensity is pretty frequent among peace-lovers, who, needing little + nourishment, have no cause to fear competition. The others, the big + eaters, take possession of estates, of hunting-grounds from which their + fellows are excluded. Ask a Wolf his opinion of a brother Wolf poaching on + his preserves. Man himself, the chief of consumers, makes for himself + frontiers armed with artillery; he sets up posts at the foot of which one + says to the other: + </p> + <p> + 'Here's my side, there's yours. That's enough: now we'll pepper each + other.' + </p> + <p> + And the rattle of the latest explosives ends the colloquy. + </p> + <p> + Happy are the peace-lovers. What do they gain by their mustering? With + them it is not a defensive system, a concerted effort to ward off the + common foe. The Halictus does not care about her neighbour's affairs. She + does not visit another's burrow; she does not allow others to visit hers. + She has her tribulations, which she endures alone; she is indifferent to + the tribulations of her kind. She stands aloof from the strife of her + fellows. Let each mind her own business and leave things at that. + </p> + <p> + But company has its attractions. He lives twice who watches the life of + others. Individual activity gains by the sight of the general activity; + the animation of each one derives fresh warmth from the fire of the + universal animation. To see one's neighbours at work stimulates one's + rivalry. And work is the great delight, the real satisfaction that gives + some value to life. The Halictus knows this well and assembles in her + numbers that she may work all the better. + </p> + <p> + Sometimes she assembles in such multitudes and over such extents of ground + as to suggest our own colossal swarms. Babylon and Memphis, Rome and + Carthage, London and Paris, those frantic hives, occur to our mind if we + can manage to forget comparative dimensions and see a Cyclopean pile in a + pinch of earth. + </p> + <p> + It was in February. The almond-tree was in blossom. A sudden rush of sap + had given the tree new life; its boughs, all black and desolate, seemingly + dead, were becoming a glorious dome of snowy satin. I have always loved + this magic of the awakening spring, this smile of the first flowers + against the gloomy bareness of the bark. + </p> + <p> + And so I was walking across the fields, gazing at the almond-trees' + carnival. Others were before me. An Osmia in a black velvet bodice and a + red woollen skirt, the Horned Osmia, was visiting the flowers, dipping + into each pink eye in search of a honeyed tear. A very small and very + modestly-dressed Halictus, much busier and in far greater numbers, was + flitting silently from blossom to blossom. Official science calls her + Halictus malachurus, K. The pretty little Bee's godfather strikes me as + ill-inspired. What has malachurus, calling attention to the softness of + the rump, to do in this connection? The name of Early Halictus would + better describe the almond-tree's little visitor. + </p> + <p> + None of the melliferous clan, in my neighbourhood at least, is stirring as + early as she is. She digs her burrows in February, an inclement month, + subject to sudden returns of frost. When none as yet, even among her near + kinswomen, dares to sally forth from winter-quarters, she pluckily goes to + work, shine the sun ever so little. Like the Zebra Halictus, she has two + generations a year, one in spring and one in summer; like her, too, she + settles by preference in the hard ruts of the country roads. + </p> + <p> + Her mole-hills, those humble mounds any two of which would go easily into + a Hen's egg, rise innumerous in my path, the path by the almond-trees + which is the happy hunting-ground of my curiosity to-day. This path is a + ribbon of road three paces wide, worn into ruts by the Mule's hoofs and + the wheels of the farm-carts. A coppice of holm-oaks shelters it from the + north wind. In this Eden with its well-caked soil, its warmth and quiet, + the little Halictus has multiplied her mole-hills to such a degree that I + cannot take a step without crushing some of them. The accident is not + serious: the miner, safe underground, will be able to scramble up the + crumbling sides of the mine and repair the threshold of the trampled home. + </p> + <p> + I make a point of measuring the density of the population. I count from + forty to sixty mole-hills on a surface of one square yard. The encampment + is three paces wide and stretches over nearly three-quarters of a mile. + How many Halicti are there in this Babylon? I do not venture to make the + calculation. + </p> + <p> + Speaking of the Zebra Halictus, I used the words hamlet, village, + township; and the expressions were appropriate. Here the term city hardly + meets the case. And what reason can we allege for these innumerable + clusters? I can see but one: the charm of living together, which is the + origin of society. Like mingles with like, without the rendering of any + mutual service; and this is enough to summon the Early Halictus to the + same way-side, even as the Herring and the Sardine assemble in the same + waters. + </p> + <p> + <a name="link2HCH0014" id="link2HCH0014"> + <!-- H2 anchor --> </a> + </p> + <div style="height: 4em;"> + <br /><br /><br /><br /> + </div> + <h2> + CHAPTER 14. THE HALICTI: PARTHENOGENESIS. + </h2> + <p> + The Halictus opens up another question, connected with one of life's + obscurest problems. Let us go back five-and-twenty years. I am living at + Orange. My house stands alone among the fields. On the other side of the + wall enclosing our yard, which faces due south, is a narrow path overgrown + with couch-grass. The sun beats full upon it; and the glare reflected from + the whitewash of the wall turns it into a little tropical corner, shut off + from the rude gusts of the north-west wind. + </p> + <p> + Here the Cats come to take their afternoon nap, with their eyes + half-closed; here the children come, with Bull, the House-dog; here also + come the haymakers, at the hottest time of the day, to sit and take their + meal and whet their scythes in the shade of the plane-tree; here the women + pass up and down with their rakes, after the hay-harvest, to glean what + they can on the niggardly carpet of the shorn meadow. It is therefore a + very much frequented footpath, were it only because of the coming and + going of our household: a thoroughfare ill-suited, one would think, to the + peaceful operations of a Bee; and nevertheless it is such a very warm and + sheltered spot and the soil is so favourable that every year I see the + Cylindrical Halictus (H. cylindricus, FAB.) hand down the site from one + generation to the next. It is true that the very matutinal, even partly + nocturnal character of the work makes the insect suffer less inconvenience + from the traffic. + </p> + <p> + The burrows cover an extent of some ten square yards, and their mounds, + which often come near enough to touch, average a distance of four inches + at the most from one another. Their number is therefore something like a + thousand. The ground just here is very rough, consisting of stones and + dust mixed with a little mould and held together by the closely interwoven + roots of the couch-grass. But, owing to its nature, it is thoroughly well + drained, a condition always in request among Bees and Wasps that have + underground cells. + </p> + <p> + Let us forget for a moment what the Zebra Halictus and the Early Halictus + have taught us. At the risk of repeating myself a little, I will relate + what I observed during my first investigations. The Cylindrical Halictus + works in May. Except among the social species, such as Common Wasps, + Bumble-bees, Ants and Hive-bees, it is the rule for each insect that + victuals its nests either with honey or game to work by itself at + constructing the home of its grubs. Among insects of the same species + there is often neighbourship; but their labours are individual and not the + result of co-operation. For instance, the Cricket-hunters, the + Yellow-winged Sphex, settle in gangs at the foot of a sandstone cliff, but + each digs her own burrow and would not suffer a neighbour to come and help + in piercing the home. + </p> + <p> + In the case of the Anthophorae, an innumerable swarm takes possession of a + sun-scorched crag, each Bee digging her own gallery and jealously + excluding any of her fellows who might venture to come to the entrance of + her hole. The Three-pronged Osmia, when boring the bramble-stalk tunnel in + which her cells are to be stacked, gives a warm reception to any Osmia + that dares set foot upon her property. + </p> + <p> + Let one of the Odyneri who make their homes in a road-side bank mistake + the door and enter her neighbour's house: she would have a bad time of it! + Let a Megachile, returning with her leafy disk in her legs, go into the + wrong basement: she would be very soon dislodged! So with the others: each + has her own home, which none of the others has the right to enter. This is + the rule, even among Bees and Wasps established in a populous colony on a + common site. Close neighbourhood implies no sort of intimate relationship. + </p> + <p> + Great therefore is my surprise as I watch the Cylindrical Halictus' + operations. She forms no society, in the entomological sense of the word: + there is no common family; and the general interest does not engross the + attention of the individual. Each mother occupies herself only with her + own eggs, builds cells and gathers honey only for her own larvae, without + concerning herself in any way with the upbringing of the others' grubs. + All that they have in common is the entrance-door and the goods-passage, + which ramifies in the ground and leads to different groups of cells, each + the property of one mother. Even so, in the blocks of flats in our large + towns, one door, one hall and one staircase lead to different floors or + different portions of a floor where each family retains its isolation and + its independence. + </p> + <p> + This common right of way is extremely easy to perceive at the time for + victualling the nests. Let us direct our attention for a while to the same + entrance-aperture, opening at the top of a little mound of earth freshly + thrown up, like that accumulated by the Ants during their works. Sooner or + later we shall see the Halicti arrive with their load of pollen, gathered + on the Cichoriaceae of the neighbourhood. + </p> + <p> + Usually, they come up one by one; but it is not rare to see three, four or + even more appearing at the same time at the mouth of one burrow. They + perch on the top of the mound and, without hurrying in front of one + another, with no sign of jealousy, they dive down the passage, each in her + turn. We need but watch their peaceful waiting, their tranquil dives, to + recognize that this indeed is a common passage to which each has as much + right as another. + </p> + <p> + When the soil is exploited for the first time and the shaft sunk slowly + from the outside to the inside, do several Cylindrical Halicti, one + relieving the other, take part in the work by which they will afterwards + profit equally? I do not believe it for a moment. As the Zebra Halictus + and the Early Halictus told me later, each miner goes to work alone and + makes herself a gallery which will be her exclusive property. The common + use of the passage comes presently, when the site, tested by experience, + is handed down from one generation to another. + </p> + <p> + A first group of cells is established, we will suppose, at the bottom of a + pit dug in virgin soil. The whole thing, cells and pit, is the work of one + insect. When the moment comes to leave the underground dwelling, the Bees + emerging from this nest will find before them an open road, or one at most + obstructed by crumbly matter, which offers less resistance than the + neighbouring soil, as yet untouched. The exit-way will therefore be the + primitive way, contrived by the mother during the construction of the + nest. All enter upon it without any hesitation, for the cells open + straight on it. All, coming and going from the cells to the bottom of the + shaft and from the shaft to the cells, will take part in the clearing, + under the stimulus of the approaching deliverance. + </p> + <p> + It is quite unnecessary here to presume among these underground prisoners + a concerted effort to liberate themselves more easily by working in + common: each is thinking only of herself and invariably returns, after + resting, to toil at the inevitable path, the path of least resistance, in + short the passage once dug by the mother and now more or less blocked up. + </p> + <p> + Among the Cylindrical Halicti, any one who wishes emerges from her cell at + her own hour, without waiting for the emergence of the others, because the + cells, grouped in small stacks, have each their special outlet opening + into the common gallery. The result of this arrangement is that all the + inhabitants of one burrow are able to assist, each doing her share, in the + clearing of the exit-shaft. When she feels fatigued, the worker retires to + her undamaged cell and another succeeds her, impatient to get out rather + than to help the first. At last the way is clear and the Halicti emerge. + They disperse over the flowers around as long as the sun is hot; when the + air cools, they go back to the burrows to spend the night there. + </p> + <p> + A few days pass and already the cares of egg-laying are at hand. The + galleries have never been abandoned. The Bees have come to take refuge + there on rainy or very windy days; most, if not all, have returned every + evening at sunset, each doubtless making for her own cell, which is still + intact and which is carefully impressed upon her memory. In a word, the + Cylindrical Halictus does not lead a wandering life; she has a fixed + residence. + </p> + <p> + A necessary consequence results from these settled habits: for the purpose + of her laying, the Bee will adopt the identical burrow in which she was + born. The entrance-gallery is ready therefore. Should it need to be + carried deeper, to be pushed in new directions, the builder has but to + extend it at will. The old cells even can serve again, if slightly + restored. + </p> + <p> + Thus resuming possession of the native burrow in view of her offspring, + the Bee, notwithstanding her instincts as a solitary worker, achieves an + attempt at social life, because there is one entrance-door and one passage + for the use of all the mothers returning to the original domicile. There + is thus a semblance of collaboration without any real co-operation for the + common weal. Everything is reduced to a family inheritance shared equally + among the heirs. + </p> + <p> + The number of these coheirs must soon be limited, for a too tumultuous + traffic in the corridor would delay the work. Then fresh passages are + opened inwards, often communicating with depths already excavated, so that + the ground at last is perforated in every direction with an inextricable + maze of winding tunnels. + </p> + <p> + The digging of the cells and the piercing of new galleries take place + especially at night. A cone of fresh earth on top of the burrow bears + evidence every morning to the overnight activity. It also shows by its + volume that several navvies have taken part in the work, for it would be + impossible for a single Halictus to extract from the ground, convey to the + surface and heap up so large a stack of rubbish in so short a time. + </p> + <p> + At sunrise, when the fields around are still wet with dew, the Cylindrical + Halictus leaves her underground passages and starts on her foraging. This + is done without animation, perhaps because of the morning coolness. There + is no joyous excitement, no humming above the burrows. The Bees come back + again, flying low, silently and heavily, their hind-legs yellow with + pollen; they alight on the earth-cone and at once dive down the vertical + chimney. Others come up the pipe and go off to their harvesting. + </p> + <p> + This journeying to and fro for provisions continues until eight or nine in + the morning. Then the heat begins to grow intense and is reflected by the + wall; then also the path is once more frequented. People pass at every + moment, coming out of the house or elsewhence. The soil is so much trodden + under foot that the little mounds of refuse surrounding each burrow soon + disappear and the site loses every sign of underground habitation. + </p> + <p> + All day long, the Halicti remain indoors. Withdrawing to the bottom of the + galleries, they occupy themselves probably in making and polishing the + cells. Next morning, new cones of rubbish appear, the result of the + night's work, and the pollen-harvest is resumed for a few hours; then + everything ceases again. And so the work goes on, suspended by day, + renewed at night and in the morning hours, until completely finished. + </p> + <p> + The passages of the Cylindrical Halictus descend to a depth of some eight + inches and branch into secondary corridors, each giving access to a set of + cells. These number six or eight to each set and are ranged side by side, + parallel with their main axis, which is almost horizontal. They are oval + at the base and contracted at the neck. Their length is nearly twenty + millimetres (.78 inch.—Translator's Note.) and their greatest width + eight. (.312 inch.—Translator's Note.) They do not consist simply of + a cavity in the ground; on the contrary, they have their own walls, so + that the group can be taken out in one piece, with a little precaution, + and removed neatly from the earth in which it is contained. + </p> + <p> + The walls are formed of fairly delicate materials, which must have been + chosen in the coarse surrounding mass and kneaded with saliva. The inside + is carefully polished and upholstered with a thin waterproof film. We will + cut short these details concerning the cells, which the Zebra Halictus has + already shown us in greater perfection, leave the home to itself and come + to the most striking feature in the life-history of the Halicti. + </p> + <p> + The Cylindrical Halictus is at work in the first days of May. It is a rule + among the Hymenoptera for the males never to take part in the fatiguing + work of nest-building. To construct cells and to amass victuals are + occupations entirely foreign to their nature. This rule seems to have no + exceptions; and the Halicti conform to it like the rest. It is therefore + only to be expected that we should see no males shooting the underground + rubbish outside the galleries. That is not their business. + </p> + <p> + But what does astonish us, when our attention is directed to it, is the + total absence of any males in the vicinity of the burrows. Although it is + the rule that the males should be idle, it is also the rule for these + idlers to keep near the galleries in course of construction, coming and + going from door to door and hovering above the work-yards to seize the + moment at which the unfecundated females will at last yield to their + importunities. + </p> + <p> + Now here, despite the enormous population, despite my careful and + incessant watch, it is impossible for me to distinguish a single male. And + yet the distinction between the sexes is of the simplest. It is not + necessary to take hold of the male. He can be recognized even at a + distance by his slenderer frame, by his long, narrow abdomen, by his red + sash. They might easily suggest two different species. The female is a + pale russet-brown; the male is black, with a few red segments to his + abdomen. Well, during the May building-operations, there is not a Bee in + sight clad in black, with a slender, red-belted abdomen; in short, not a + male. + </p> + <p> + Though the males do not come to visit the environs of the burrows, they + might be elsewhere, particularly on the flowers where the females go + plundering. I did not fail to explore the fields, insect-net in hand. My + search was invariably fruitless. On the other hand, those males, now + nowhere to be found, are plentiful later, in September, along the borders + of the paths, on the close-set flowers of the eringo. + </p> + <p> + This singular colony, reduced exclusively to mothers, made me suspect the + existence of several generations a year, whereof one at least must possess + the other sex. I continued therefore, when the building-who was over, to + keep a daily watch on the establishment of the Cylindrical Halictus, in + order to seize the favourable moment that would verify my suspicions. For + six weeks, solitude reigned above the burrows: not a single Halictus + appeared; and the path, trodden by the wayfarers, lost its little heaps of + rubbish, the only signs of the excavations. There was nothing outside to + show that the warmth down below was hatching populous swarms. + </p> + <p> + July comes and already a few little mounds of fresh earth betoken work + going on underground in preparation for an exodus in the near future. As + the males, among the Hymenoptera, are generally further advanced than the + females and quit their natal cells earlier, it was important that I should + witness the first exits made, so as to dispel the least shadow of a doubt. + A violent exhumation would have a great advantage over the natural exit: + it would place the population of the burrows immediately under my eyes, + before the departure of either sex. In this way, nothing could escape from + me and I was dispensed from a watch which, for all its attentiveness, was + not to be relied upon absolutely. I therefore resolve upon a + reconnaissance with the spade. + </p> + <p> + I dig down to the full depth of the galleries and remove large lumps of + earth which I take in my hands and break very carefully so as to examine + all the parts that may contain cells. Halicti in the perfect state + predominate, most of them still lodged in their unbroken chambers. Though + they are not quite so numerous, there are also plenty of pupae. I collect + them of every shade of colour, from dead-white, the sign of a recent + transformation, to smoky-brown, the mark of an approaching metamorphosis. + Larvae, in small quantities, complete the harvest. They are in the state + of torpor that precedes the appearance of the pupa. + </p> + <p> + I prepare boxes with a bed of fresh, sifted earth to receive the larvae + and the pupae, which I lodge each in a sort of half-cell formed by the + imprint of my finger. I will await the transformation to decide to which + sex they belong. As for the perfect insects, they are inspected, counted + and at once released. + </p> + <p> + In the very unlikely supposition that the distribution of the sexes might + vary in different parts of the colony, I make a second excavation, at a + few yards' distance from the other. It supplies me with another collection + both of perfect insects and of pupae and larvae. + </p> + <p> + When the metamorphosis of the laggards is completed, which does not take + many days, I proceed to take a general census. It gives me two hundred and + fifty Halicti. Well, in this number of Bees, collected in the burrow + before any have emerged, I perceive none, absolutely none but females; or, + to be mathematically accurate, I find just one male, one alone; and he is + so small and feeble that he dies without quite succeeding in divesting + himself of his nymphal bands. This solitary male is certainly accidental. + A female population of two hundred and forty-nine Halicti implies other + males than this abortion, or rather implies none at all. I therefore + eliminate him as an accident of no value and conclude that, in the + Cylindrical Halictus, the July generation consists of females only. + </p> + <p> + The building-operations start again in the second week of July. The + galleries are restored and lengthened; new cells are fashioned and the old + ones repaired. Follow the provisioning, the laying of the eggs, the + closing of the cells; and, before July is over, there is solitude again. + Let me also say that, during the building-period, not a male appears in + sight, a fact which adds further proof to that already supplied by my + excavations. + </p> + <p> + With the high temperature of this time of the year, the development of the + larvae makes rapid progress: a month is sufficient for the various stages + of the metamorphosis. On the 24th of August there are once more signs of + life above the burrows of the Cylindrical Halictus, but under very + different conditions. For the first time, both sexes are present. Males, + so easily recognized by their black livery and their slim abdomen adorned + with a red ring, hover backwards and forwards, almost level with the + ground. They fuss about from burrow to burrow. A few rare females come out + for a moment and then go in again. + </p> + <p> + I proceed to make an excavation with my spade; I gather indiscriminately + whatever I come across. Larvae are very scarce; pupae abound, as do + perfect insects. The list of my captures amounts to eighty males and + fifty-eight females. The males, therefore, hitherto impossible to + discover, either on the flowers around or in the neighbourhood of the + burrows, could be picked up to-day by the hundred, if I wished. They + outnumber the females by about four to three; they are also further + developed, in accordance with the general rule, for most of the backward + pupae give me only females. + </p> + <p> + Once the two sexes had appeared, I expected a third generation that would + spend the winter in the larval state and recommence in May the annual + cycle which I have just described. My anticipation proved to be at fault. + Throughout September, when the sun beats upon the burrows, I see the males + flitting in great numbers from one shaft to the other. Sometimes a female + appears, returning from the fields, but with no pollen on her legs. She + seeks her gallery, finds it, dives down and disappears. + </p> + <p> + The males, as though indifferent to her arrival, offer her no welcome, do + not harass her with their amorous pursuits; they continue to visit the + doors of the burrows with a winding and oscillating flight. For two + months, I follow their evolutions. If they set foot on earth, it is to + descend forthwith into some gallery that suits them. + </p> + <p> + It is not uncommon to see several of them on the threshold of the same + burrow. Then each awaits his turn to enter; they are as peaceable in their + relations as the females who are joint owners of a burrow. At other times, + one wants to go in as a second is coming out. This sudden encounter + produces no strife. The one leaving the hole withdraws a little to one + side to make enough room for two; the other slips past as best he can. + These peaceful meetings are all the more striking when we consider the + usual rivalry between males of the same species. + </p> + <p> + No rubbish-mound stands at the mouth of the shafts, showing that the + building has not been resumed; at the most, a few crumbs of earth are + heaped outside. And by whom, pray? By the males and by them alone. The + lazy sex has bethought itself of working. It turns navvy and shoots out + grains of earth that would interfere with its continual entrances and + exits. For the first time I witness a custom which no Hymenopteron had yet + shown me: I see the males haunting the interior of the burrows with an + assiduity equalling that of the mothers employed in nest-building. + </p> + <p> + The cause of these unwonted operations soon stands revealed. The females + seen flitting above the burrows are very rare; the majority of the + feminine population remain sequestered under ground, do not perhaps come + out once during the whole of the latter part of summer. Those who do + venture out go in again soon, empty-handed of course and always without + any amorous teasing from the males, a number of whom are hovering above + the burrows. + </p> + <p> + On the other hand, watch as carefully as I may, I do not discover a single + act of pairing out of doors. The weddings are clandestine, therefore, and + take place under ground. This explains the males' fussy visits to the + doors of the galleries during the hottest hours of the day, their + continual descents into the depths and their continual reappearances. They + are looking for the females cloistered in the retirement of the cells. + </p> + <p> + A little spade-work soon turns suspicion into certainty. I unearth a + sufficient number of couples to prove to me that the sexes come together + underground. When the marriage is consummated, the red-belted one quits + the spot and goes to die outside the burrow, after dragging from flower to + flower the bit of life that remains to him. The other shuts herself up in + her cell, there to await the return of the month of May. + </p> + <p> + September is spent by the Halictus solely in nuptial celebrations. + Whenever the sky is fine, I witness the evolutions of the males above the + burrows, with their continual entrances and exits; should the sun be + veiled, they take refuge down the passages. The more impatient, + half-hidden in the pit, show their little black heads outside, as though + peeping for the least break in the clouds that will allow them to pay a + brief visit to the flowers round about. They also spend the night in the + burrows. In the morning, I attend their levee; I see them put their head + to the window, take a look at the weather and then go in again until the + sun beats on the encampment. + </p> + <p> + The same mode of life is continued throughout October, but the males + become less numerous from day to day as the stormy season approaches and + fewer females remain to be wooed. By the time that the first cold weather + comes, in November, complete solitude reigns over the burrows. I once more + have recourse to the spade. I find none but females in their cells. There + is not one male left. All have vanished, all are dead, the victims of + their life of pleasure and of the wind and rain. Thus ends the cycle of + the year for the Cylindrical Halictus. + </p> + <p> + In February, after a hard winter, when the snow had lain on the ground for + a fortnight, I wanted once more to look into the matter of my Halicti. I + was in bed with pneumonia and at the point of death, to all appearances. I + had little or no pain, thank God, but extreme difficulty in living. With + the little lucidity left to me, being able to do no other sort of + observing, I observed myself dying; I watched with a certain interest the + gradual falling to pieces of my poor machinery. Were it not for the terror + of leaving my family, who were still young, I would gladly have departed. + The after-life must have so many higher and fairer truths to teach us. + </p> + <p> + My hour had not yet come. When the little lamps of thought began to + emerge, all flickering, from the dusk of unconsciousness, I wished to take + leave of the Hymenopteron, my fondest joy, and first of all of my + neighbour, the Halictus. My son Emile took the spade and went and dug the + frozen ground. Not a male was found, of course; but there were plenty of + females, numbed with the cold in their cells. + </p> + <p> + A few were brought for me to see. Their little chambers showed no + efflorescence of rime, with which all the surrounding earth was coated. + The waterproof varnish had been wonderfully efficacious. As for the + anchorites, roused from their torpor by the warmth of the room, they began + to wander about my bed, where I followed them vaguely with my fading eyes. + </p> + <p> + May came, as eagerly awaited by the sick man as by the Halicti. I left + Orange for Serignan, my last stage, I expect. While I was moving, the Bees + resumed their building. I gave them a regretful glance, for I had still + much to learn in their company. I have never since met with such a mighty + colony. + </p> + <p> + These old observations on the habits of the Cylindrical Halictus may now + be followed by a general summary which will incorporate the recent data + supplied by the Zebra Halictus and the Early Halictus. + </p> + <p> + The females of the Cylindrical Halictus whom I unearth from November + onwards are evidently fecundated, as is proved by the assiduity of the + males during the preceding two months and most positively confirmed by the + couples discovered in the course of my excavations. These females spend + the winter in their cells, as do many of the early-hatching melliferous + insects, such as Anthophorae and Mason-bees, who build their nests in the + spring, the larvae reaching the perfect state in the summer and yet + remaining shut up in their cells until the following May. But there is + this great difference in the case of the Cylindrical Halictus, that in the + autumn the females leave their cells for a time to receive the males under + ground. The couples pair and the males perish. Left alone, the females + return to their cells, where they spend the inclement season. + </p> + <p> + The Zebra Halicti, studied first at Orange and then, under better + conditions, at Serignan, in my own enclosure, have not these subterranean + customs: they celebrate their weddings amid the joys of the light, the sun + and the flowers. I see the first males appear in the middle of September, + on the centauries. Generally there are several of them courting the same + bride. Now one, then another, they swoop upon her suddenly, clasp her, + leave her, seize hold of her again. Fierce brawls decide who shall possess + her. One is accepted and the others decamp. With a swift and angular + flight, they go from flower to flower, without alighting. They hover on + the wing, looking about them, more intent on pairing than on eating. + </p> + <p> + The Early Halictus did not supply me with any definite information, partly + through my own fault, partly through the difficulty of excavation in a + stony soil, which calls for the pick-axe rather than the spade. I suspect + her of having the nuptial customs of the Cylindrical Halictus. + </p> + <p> + There is another difference, which causes certain variations of detail in + these customs. In the autumn, the females of the Cylindrical Halictus + leave their burrows seldom or not at all. Those who do go out invariably + come back after a brief halt upon the flowers. All pass the winter in the + natal cells. On the other hand, those of the Zebra Halictus move their + quarters, meet the males outside and do not return to the burrows, which + my autumn excavations always find deserted. They hibernate in the first + hiding-places that offer. + </p> + <p> + In the spring, the females, fecundated since the autumn, come out: the + Cylindrical Halicti from their cells, the Zebra Halicti from their various + shelters, the Early Halicti apparently from their chambers, like the + first. They work at their nests in the absence of any male, as do also the + Social Wasps, whose whole brood has perished excepting a few mothers also + fecundated in the autumn. In both cases, the assistance of the males is + equally real, only it has preceded the laying by about six months. + </p> + <p> + So far, there is nothing new in the life of the Halicti; but here is where + the unexpected appears: in July, another generation is produced; and this + time without males. The absence of masculine assistance is no longer a + mere semblance here, due to an earlier fecundation: it is a reality + established beyond a doubt by the continuity of my observations and by my + excavations during the summer season, before the emergence of the new + Bees. At this period, a little before July, if my spade unearth the cells + of any one of my three Halicti, the result is always females, nothing but + females, with exceedingly rare exceptions. + </p> + <p> + True, it may be said that the second progeny is due to the mothers who + knew the males in autumn and who would be able to nidify twice a year. The + suggestion is not admissible. The Zebra Halictus confirms what I say. She + shows us the old mothers no longer leaving the home but mounting guard at + the entrance to the burrows. No harvesting- or pottery-work is possible + with these absorbing doorkeeping-functions. Therefore there is no new + family, even admitting that the mothers' ovaries are not depleted. + </p> + <p> + I do not know if a similar argument is valid in the case of the + Cylindrical Halictus. Has she any general survivors? As my attention had + not yet been directed on this point in the old days, when I had the insect + at my door, I have no records to go upon. For all that, I am inclined to + think that the portress of the Zebra Halictus is unknown here. The reason + of this absence would be the number of workers at the start. + </p> + <p> + In May, the Zebra Halictus, living by herself in her winter retreat, + founds her house alone. When her daughters succeed her, in July, she is + the only grandmother in the establishment and the post of portress falls + to her. With the Cylindrical Halictus, the conditions are different. Here + the May workers are many in the same burrow, where they dwell in common + during the winter. Supposing that they survive when the business of the + household is finished, to whom will the office of overseer fall? Their + number is so great and they are all so full of zeal that disorder would be + inevitable. But we can leave this small matter unsettled pending further + information. + </p> + <p> + The fact remains that females, females exclusively, have come out of the + eggs laid in May. They have descendants, of that there is no room for + doubt; they procreate though there are no males in their time. From this + generation by a single sex, there spring, two months later, males and + females. These mate; and the same order of things recommences. + </p> + <p> + To sum up, judging by the three species that form the subject of my + investigations, the Halicti have two generations a year: one in the + spring, issuing from the mothers who have lived through the winter after + being fecundated in the autumn; the other in the summer, the fruit of + parthenogenesis, that is to say, of reproduction by the powers of the + mother alone. Of the union of the two sexes, females alone are born; + parthenogenesis gives birth at the same time to females and males. + </p> + <p> + When the mother, the original genitrix, has been able once to dispense + with a coadjutor, why does she need one later? What is the puny idler + there for? He was unnecessary. Why does he become necessary now? Shall we + ever obtain a satisfactory answer to the question? It is doubtful. + However, without much hope of succeeding we will one day consult the + Gall-fly, who is better-versed than we in the tangled problem of the + sexes. + </p> + <p> + INDEX. + </p> + <p> + Alpine Odynerus. + </p> + <p> + Amadeus' Eumenes. + </p> + <p> + Ammophila (see also Hairy Ammophila). + </p> + <p> + Andrena. + </p> + <p> + Andrenoid Osmia. + </p> + <p> + Ant. + </p> + <p> + Anthidium (see the varieties below, Cotton-bee, Resin Bee). + </p> + <p> + Anthidium bellicosum. + </p> + <p> + Anthidium cingulatum (see Girdled Anthidium). + </p> + <p> + Anthidium diadema (see Diadem Anthidium). + </p> + <p> + Anthidium florentinum (see Florentine Anthidium). + </p> + <p> + Anthidium Latreillii (see Latreille's Resin-bee). + </p> + <p> + Anthidium manicatum (see Manicate Anthidium). + </p> + <p> + Anthidium quadrilobum (see Four-lobed Resin-bee). + </p> + <p> + Anthidium scapulare (see Scapular Anthidium). + </p> + <p> + Anthidium septemdentatum (see Seven-pronged Resin-bee). + </p> + <p> + Anthocopa papaveris (see Upholsterer-bee). + </p> + <p> + Anthophora (see also Anthophora of the Walls, Hairy-footed Anthophora, + Masked Anthophora). + </p> + <p> + Anthophora of the Walls. + </p> + <p> + Anthophora parietina (see Anthophora of the Walls). + </p> + <p> + Anthophora pilipes (see Hairy-footed Anthophora). + </p> + <p> + Anthrax (see Anthrax sinuata). + </p> + <p> + Anthrax sinuata. + </p> + <p> + Aphis (see Plant-louse). + </p> + <p> + Archimedes. + </p> + <p> + Augustus, the Emperor. + </p> + <p> + Bee. + </p> + <p> + Beetle. + </p> + <p> + Bembex. + </p> + <p> + Black, Adam and Charles. + </p> + <p> + Black Plant-louse. + </p> + <p> + Black Psen. + </p> + <p> + Black-tipped Leaf-cutter. + </p> + <p> + Blue Osmia. + </p> + <p> + Book-louse. + </p> + <p> + Brown Snail. + </p> + <p> + Bulimulus radiatus. + </p> + <p> + Bumble-bee. + </p> + <p> + Calicurgus (see Pompilus). + </p> + <p> + Capricorn. + </p> + <p> + Carpenter-bee. + </p> + <p> + Cat. + </p> + <p> + Cemonus unicolor. + </p> + <p> + Cerambyx (see Capricorn). + </p> + <p> + Ceratina (see also the varieties below). + </p> + <p> + Ceratina albilabris. + </p> + <p> + Ceratina callosa. + </p> + <p> + Ceratina chalcites. + </p> + <p> + Ceratina coerulea. + </p> + <p> + Cerceris. + </p> + <p> + Cetonia. + </p> + <p> + Chaffinch. + </p> + <p> + Chalicodoma (see Mason-bee). + </p> + <p> + Chrysis flammea. + </p> + <p> + Cockroach. + </p> + <p> + Coelyoxis caudata. + </p> + <p> + Coelyoxis octodentata. + </p> + <p> + Colletes. + </p> + <p> + Common Snail. + </p> + <p> + Common Wasp. + </p> + <p> + Cotton-bee (see also the varieties of Anthidium). + </p> + <p> + Crayfish. + </p> + <p> + Cricket. + </p> + <p> + Crioceris merdigera (see Lily-beetle). + </p> + <p> + Cryptus bimaculatus. + </p> + <p> + Cryptus gyrator. + </p> + <p> + Cylindrical Halictus. + </p> + <p> + Darwin, Charles Robert. + </p> + <p> + Decticus verrucivorus. + </p> + <p> + Devillario, Henri. + </p> + <p> + Diadem Anthidium. + </p> + <p> + Dioxys cincta. + </p> + <p> + Dog. + </p> + <p> + Dragon-fly. + </p> + <p> + Dryden, John. + </p> + <p> + Dufour, Jean Marie Leon. + </p> + <p> + Dung-beetle. + </p> + <p> + Dzierzon, Johann. + </p> + <p> + Early Halictus. + </p> + <p> + Earth-worm. + </p> + <p> + Earwig. + </p> + <p> + Epeira (see Garden Spider). + </p> + <p> + Ephialtes divinator. + </p> + <p> + Ephialtes mediator. + </p> + <p> + Ephippiger. + </p> + <p> + Eumenes Amadei (see Amadeus' Eumenes). + </p> + <p> + Euritema rubicola. + </p> + <p> + Fabre, Emile, the author's son. + </p> + <p> + Fabricius, Johann Christian. + </p> + <p> + Feeble Leaf-cutter. + </p> + <p> + Field-mouse. + </p> + <p> + Florentine Anthidium. + </p> + <p> + Fly (see also House-fly). + </p> + <p> + Foenus pyrenaicus. + </p> + <p> + Four-lobed Resin-bee. + </p> + <p> + Franklin, Benjamin. + </p> + <p> + Garden Snail. + </p> + <p> + Garden Spider. + </p> + <p> + Girdled Anthidium. + </p> + <p> + Girdled Snail (see Brown Snail). + </p> + <p> + Gnat. + </p> + <p> + Golden Osmia. + </p> + <p> + Goldfinch. + </p> + <p> + Grasshopper (see also Great Green Grasshopper). + </p> + <p> + Great Green Grasshopper. + </p> + <p> + Great Peacock Moth. + </p> + <p> + Green Grasshopper (see Ephippiger, Great Green Grasshopper). + </p> + <p> + Green Osmia. + </p> + <p> + Grey Lizard. + </p> + <p> + Hairy Ammophila. + </p> + <p> + Hairy-footed Anthophora. + </p> + <p> + Halictus (see also the varieties below). + </p> + <p> + Halictus cylindricus (see Cylindrical Halictus). + </p> + <p> + Halictus malachurus (see Early Halictus). + </p> + <p> + Halictus zebrus (see Zebra Halictus). + </p> + <p> + Hare-footed Leaf-cutter. + </p> + <p> + Helix algira. + </p> + <p> + Helix aspersa (see Common Snail). + </p> + <p> + Helix caespitum (see Garden Snail). + </p> + <p> + Helix nemoralis. + </p> + <p> + Helix striata. + </p> + <p> + Heriades rubicola. + </p> + <p> + Herring. + </p> + <p> + Hive-bee. + </p> + <p> + Honey-bee (see Hive-bee). + </p> + <p> + Horned Osmia. + </p> + <p> + House-dog (see Dog). + </p> + <p> + House-fly. + </p> + <p> + Kid. + </p> + <p> + Kirby, William. + </p> + <p> + La Fontaine, Jean de. + </p> + <p> + Lamb. + </p> + <p> + Languedocian Sphex. + </p> + <p> + Lanius collurio (see Red-backed Shrike). + </p> + <p> + La Palice, Jacques de Chabannes, Seigneur de. + </p> + <p> + Latreille, Pierre Andre. + </p> + <p> + Latreille's Osmia. + </p> + <p> + Latreille's Resin-bee. + </p> + <p> + Leaf-cutter, Leaf-cutting Bee (see Megachile). + </p> + <p> + Leaf-insect. + </p> + <p> + Leucopsis. + </p> + <p> + Lily-beetle. + </p> + <p> + Lithurgus (see also the varieties below). + </p> + <p> + Lithurgus chrysurus. + </p> + <p> + Lithurgus cornutus. + </p> + <p> + Lizard (see also Grey Lizard). + </p> + <p> + Locust. + </p> + <p> + Locusta viridissima (see Great Green Grasshopper). + </p> + <p> + Macmillan Co. + </p> + <p> + "Mademoiselle Mori", author of. + </p> + <p> + Manicate Anthidium. + </p> + <p> + Mantis, Mantis religiosa (see Praying Mantis). + </p> + <p> + Masked Anthophora. + </p> + <p> + Mason-bee (see also the varieties below). + </p> + <p> + Mason-bee of the Pebbles (see Mason-bee of the Walls). + </p> + <p> + Mason-bee of the Sheds. + </p> + <p> + Mason-bee of the Shrubs. + </p> + <p> + Mason-bee of the Walls. + </p> + <p> + May-fly. + </p> + <p> + Meade-Waldo, Geoffrey. + </p> + <p> + Megachile (see also the varieties below). + </p> + <p> + Megachile albocincta (see White-girdled Leaf-cutter). + </p> + <p> + Megachile apicalis (see Black-tipped Leaf-cutter). + </p> + <p> + Megachile argentata (see Silvery Leaf-cutter). + </p> + <p> + Megachile Dufourii (see Silky Leaf-cutter). + </p> + <p> + Megachile imbecilla (see Feeble Leaf-cutter). + </p> + <p> + Megachile lagopoda (see Hare-footed Leaf-cutter). + </p> + <p> + Megachile sericans (see Silky Leaf-cutter). + </p> + <p> + Melitta (see Colletes). + </p> + <p> + Miall, Bernard. + </p> + <p> + Midwife Toad. + </p> + <p> + Morawitz' Osmia. + </p> + <p> + Odynerus (see also the varieties below) + </p> + <p> + Odynerus alpestris (see Alpine Odynerus). + </p> + <p> + Odynerus delphinalis. + </p> + <p> + Odynerus rubicola. + </p> + <p> + Oil-beetle. + </p> + <p> + Omalus auratus. + </p> + <p> + Osmia (see also the varieties below). + </p> + <p> + Osmia andrenoides (see Andrenoid Osmia). + </p> + <p> + Osmia aurulenta (see Golden Osmia). + </p> + <p> + Osmia cornuta (see Horned Osmia). + </p> + <p> + Osmia cyanea (see Blue Osmia). + </p> + <p> + Osmia cyanoxantha. + </p> + <p> + Osmia detrita (see Ragged Osmia). + </p> + <p> + Osmia Latreillii (see Latreille's Osmia). + </p> + <p> + Osmia Morawitzi (see Morawitz' Osmia). + </p> + <p> + Osmia parvula (see Tiny Osmia). + </p> + <p> + Osmia rufo-hirta (see Red Osmia). + </p> + <p> + Osmia tricornis (see Three-horned Osmia). + </p> + <p> + Osmia tridentata (see Three-pronged Osmia). + </p> + <p> + Osmia versicolor (see Variegated Osmia). + </p> + <p> + Osmia viridana (see Green Osmia). + </p> + <p> + Pelopaeus. + </p> + <p> + Perez, Professor Jean. + </p> + <p> + Philanthus (see Philanthus apivorus). + </p> + <p> + Philanthus apivorus. + </p> + <p> + Plant-louse (see also Black Plant-louse). + </p> + <p> + Pompilus. + </p> + <p> + Praying Mantis. + </p> + <p> + Prosopis confusa. + </p> + <p> + Psen atratus (see Black Psen). + </p> + <p> + Rabelais, Francois. + </p> + <p> + Ragged Osmia. + </p> + <p> + Reaumur, Rene Antoine Ferchault de. + </p> + <p> + Red-backed Shrike. + </p> + <p> + Red-Osmia. + </p> + <p> + Resin-bee (see also the varieties). + </p> + <p> + Ringed Calicurgus (see Pompilus). + </p> + <p> + Rodwell, Miss Frances. + </p> + <p> + Rosechafer (see Cetonia). + </p> + <p> + Sapyga (see Spotted Sapyga). + </p> + <p> + Sardine. + </p> + <p> + Scapular Anthidium. + </p> + <p> + Scolia. + </p> + <p> + Scorpion. + </p> + <p> + Seven-pronged Resin-bee. + </p> + <p> + Shrike (see Red-backed Shrike). + </p> + <p> + Silky Leaf-cutter. + </p> + <p> + Silvery Leaf-cutter. + </p> + <p> + Snail (see also the varieties) + </p> + <p> + Social Wasp (see Common Wasp). + </p> + <p> + Solenius lapidarius. + </p> + <p> + Solenius vagus. + </p> + <p> + Sophocles. + </p> + <p> + Sparrow. + </p> + <p> + Spence, William. + </p> + <p> + Sphex (see also Languedocian Sphex, Yellow-winged Sphex.) + </p> + <p> + Spotted Sapyga. + </p> + <p> + Stick-insect. + </p> + <p> + Stizus. + </p> + <p> + Tachina. + </p> + <p> + Tachytes. + </p> + <p> + Tarantula. + </p> + <p> + Teixeira de Mattos, Alexander. + </p> + <p> + Termite. + </p> + <p> + Three-horned Osmia. + </p> + <p> + Three-pronged Osmia. + </p> + <p> + Tiberius, the Emperor. + </p> + <p> + Tiny Osmia. + </p> + <p> + Tripoxylon figulus. + </p> + <p> + Unarmed Zonitis (see Zonitis mutica). + </p> + <p> + Upholsterer-bee. + </p> + <p> + Variegated Osmia. + </p> + <p> + Virgil. + </p> + <p> + Wasp (see also Common Wasp). + </p> + <p> + Weaving Spider. + </p> + <p> + Weevil. + </p> + <p> + White-girdled Leaf-cutter. + </p> + <p> + Wolf. + </p> + <p> + Worm (see Earth-worm). + </p> + <p> + Xylocopa violacea (see Carpenter-bee). + </p> + <p> + Yellow-winged Sphex. + </p> + <p> + Zebra Halictus. + </p> + <p> + Zonitis mutica. + </p> + <p> + <br /><br /><br /><br /> + </p> +<pre xml:space="preserve"> + + + + + +End of Project Gutenberg's Bramble-bees and Others, by J. 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Henri Fabre + +Posting Date: January 17, 2009 [EBook #3421] +Release Date: September, 2002 + +Language: English + +Character set encoding: ASCII + +*** START OF THIS PROJECT GUTENBERG EBOOK BRAMBLE-BEES AND OTHERS *** + + + + +Produced by Sue Asscher + + + + + +BRAMBLE-BEES AND OTHERS + +by J. HENRI FABRE + + + + +TRANSLATED BY ALEXANDER TEIXEIRA DE MATTOS, F.Z.S. + +TRANSLATOR'S NOTE. + +In this volume I have collected all the essays on Wild Bees scattered +through the "Souvenirs entomologiques," with the exception of those on +the Chalicodomae, or Mason-bees proper, which form the contents of a +separate volume entitled "The Mason-bees." + +The first two essays on the Halicti (Chapters 12 and 13) have already +appeared in an abbreviated form in "The Life and Love of the Insect," +translated by myself and published by Messrs. A. & C. Black (in America +by the Macmillan Co.) in 1911. With the greatest courtesy and kindness, +Messrs. Black have given me their permission to include these two +chapters in the present volume; they did so without fee or consideration +of any kind, merely on my representation that it would be a great pity +if this uniform edition of Fabre's Works should be rendered incomplete +because certain essays formed part of volumes of extracts previously +published in this country. Their generosity is almost unparalleled in my +experience; and I wish to thank them publicly for it in the name of +the author, of the French publishers and of the English and American +publishers, as well as in my own. + +Of the remaining chapters, one or two have appeared in the "English +Review" or other magazines; but most of them now see the light in +English for the first time. + +I have once more, as in the case of "The Mason-bees," to thank Miss +Frances Rodwell for the help which she has given me in the work +of translation and research; and I am also grateful for much kind +assistance received from the staff of the Natural History Museum and +from Mr. Geoffrey Meade-Waldo in particular. + +ALEXANDER TEIXEIRA DE MATTOS. + +Chelsea, 1915. + + + + +CONTENTS. + +TRANSLATOR'S NOTE. + +CHAPTER 1. BRAMBLE-DWELLERS. + +CHAPTER 2. THE OSMIAE. + +CHAPTER 3. THE DISTRIBUTION OF THE SEXES. + +CHAPTER 4. THE MOTHER DECIDES THE SEX OF THE EGG. + +CHAPTER 5. PERMUTATIONS OF SEX. + +CHAPTER 6. INSTINCT AND DISCERNMENT. + +CHAPTER 7. ECONOMY OF ENERGY. + +CHAPTER 8. THE LEAF-CUTTERS. + +CHAPTER 9. THE COTTON-BEES. + +CHAPTER 10. THE RESIN-BEES. + +CHAPTER 11. THE POISON OF THE BEE. + +CHAPTER 12. THE HALICTI: A PARASITE. + +CHAPTER 13. THE HALICTI: THE PORTRESS. + +CHAPTER 14. THE HALICTI: PARTHENOGENESIS. + +INDEX. + + + + +CHAPTER 1. BRAMBLE-DWELLERS. + +The peasant, as he trims his hedge, whose riotous tangle threatens to +encroach upon the road, cuts the trailing stems of the bramble a foot +or two from the ground and leaves the root-stock, which soon dries up. +These bramble-stumps, sheltered and protected by the thorny brushwood, +are in great demand among a host of Hymenoptera who have families to +settle. The stump, when dry, offers to any one that knows how to use it +a hygienic dwelling, where there is no fear of damp from the sap; its +soft and abundant pith lends itself to easy work; and the top offers a +weak spot which makes it possible for the insect to reach the vein of +least resistance at once, without cutting away through the hard +ligneous wall. To many, therefore, of the Bee and Wasp tribe, whether +honey-gatherers or hunters, one of these dry stalks is a valuable +discovery when its diameter matches the size of its would-be +inhabitants; and it is also an interesting subject of study to the +entomologist who, in the winter, pruning-shears in hand, can gather in +the hedgerows a faggot rich in small industrial wonders. Visiting the +bramble-bushes has long been one of my favourite pastimes during the +enforced leisure of the wintertime; and it is seldom but some new +discovery, some unexpected fact, makes up to me for my torn fingers. + +My list, which is still far from being complete, already numbers nearly +thirty species of bramble-dwellers in the neighbourhood of my house; +other observers, more assiduous than I, exploring another region and one +covering a wider range, have counted as many as fifty. I give at foot an +inventory of the species which I have noted. + +(Bramble-dwelling insects in the neighbourhood of Serignan [Vaucluse]: + + 1. MELLIFEROUS HYMENOPTERA. + Osmia tridentata, DUF. and PER. + Osmia detrita, PEREZ. + Anthidium scapulare, LATR. + Heriades rubicola, PEREZ. + Prosopis confusa, SCHENCK. + Ceratina chalcites, GERM. + Ceratina albilabris, FAB. + Ceratina callosa, FAB. + Ceratina coerulea, VILLERS. + + 2. HUNTING HYMENOPTERA. + Solenius vagus, FAB. (provisions, Diptera). + Solenius lapidarius, LEP. (provisions, Spiders?). + Cemonus unicolor, PANZ. (provisions, Plant-lice). + Psen atratus (provisions, Black Plant-lice). + Tripoxylon figulus, LIN. (provisions, Spiders). + A Pompilus, unknown (provisions, Spiders). + Odynerus delphinalis, GIRAUD. + + 3. PARASITICAL HYMENOPTERA. + A Leucopsis, unknown (parasite of Anthidium scapulare). + A small Scoliid, unknown (parasite of Solenius vagus). + Omalus auratus (parasite of various bramble-dwellers). + Cryptus bimaculatus, GRAV. (parasite of Osmia detrita). + Cryptus gyrator, DUF. (parasite of Tripoxylon figulus). + Ephialtes divinator, ROSSI (parasite of Cemonus unicolor). + Ephialtes mediator, GRAV. (parasite of Psen atratus). + Foenus pyrenaicus, GUERIN. + Euritoma rubicola, J. GIRAUD (parasite of Osmia detrita). + + 4. COLEOPTERA. + Zonitis mutica, FAB. (parasite of Osmia tridentata). + +Most of these insects have been submitted to a learned expert, Professor +Jean Perez, of Bordeaux. I take this opportunity of renewing my thanks +for his kindness in identifying them for me.--Author's Note.) + +They include members of very diverse corporations. Some, more +industrious and equipped with better tools, remove the pith from the dry +stem and thus obtain a vertical cylindrical gallery, the length of which +may be nearly a cubit. This sheath is next divided, by partitions, into +more or less numerous storeys, each of which forms the cell of a larva. +Others, less well-endowed with strength and implements, avail themselves +of the old galleries of other insects, galleries that have been +abandoned after serving as a home for their builder's family. Their only +work is to make some slight repairs in the ruined tenement, to clear the +channel of its lumber, such as the remains of cocoons and the litter of +shattered ceilings, and lastly to build new partitions, either with +a plaster made of clay or with a concrete formed of pith-scrapings +cemented with a drop of saliva. + +You can tell these borrowed dwellings by the unequal size of the +storeys. When the worker has herself bored the channel, she economizes +her space: she knows how costly it is. The cells, in that case, are all +alike, the proper size for the tenant, neither too large nor too small. +In this box, which has cost weeks of labour, the insect has to house the +largest possible number of larvae, while allotting the necessary amount +of room to each. Method in the superposition of the floors and economy +of space are here the absolute rule. + +But there is evidence of waste when the insect makes use of a bramble +hollowed by another. This is the case with Tripoxylon figulus. To obtain +the store-rooms wherein to deposit her scanty stock of Spiders, she +divides her borrowed cylinder into very unequal cells, by means of +slender clay partitions. Some are a centimetre (.39 inch.--Translator's +Note.) deep, the proper size for the insect; others are as much as two +inches. These spacious rooms, out of all proportion to the occupier, +reveal the reckless extravagance of a casual proprietress whose +title-deeds have cost her nothing. + +But, whether they be the original builders or labourers touching up the +work of others, they all alike have their parasites, who constitute +the third class of bramble-dwellers. These have neither galleries to +excavate nor victuals to provide; they lay their egg in a strange cell; +and their grub feeds either on the provisions of the lawful owner's +larva or on that larva itself. + +At the head of this population, as regards both the finish and the +magnitude of the structure, stands the Three-pronged Osmia (Osmia +tridentata, DUF. and PER.), to whom this chapter shall be specially +devoted. Her gallery, which has the diameter of a lead pencil, sometimes +descends to a depth of twenty inches. It is at first almost exactly +cylindrical; but, in the course of the victualling, changes occur which +modify it slightly at geometrically determined distances. The work of +boring possesses no great interest. In the month of July, we see the +insect, perched on a bramble-stump, attack the pith and dig itself a +well. When this is deep enough, the Osmia goes down, tears off a few +particles of pith and comes up again to fling her load outside. This +monotonous labour continues until the Bee deems the gallery long enough, +or until, as often happens, she finds herself stopped by an impassable +knot. + +Next comes the ration of honey, the laying of the egg and the +partitioning, the last a delicate operation to which the insect proceeds +by degrees from the base to the top. At the bottom of the gallery, a +pile of honey is placed and an egg laid upon the pile; then a partition +is built to separate this cell from the next, for each larva must +have its special chamber, about a centimetre and a half (.58 +inch.--Translator's Note.) long, having no communication with the +chambers adjoining. The materials employed for this partition are +bramble-sawdust, glued into a paste with the insects' saliva. Whence are +these materials obtained? Does the Osmia go outside, to gather on the +ground the rubbish which she flung out when boring the cylinder? On the +contrary, she is frugal of her time and has better things to do than to +pick up the scattered particles from the soil. The channel, as I said, +is at first uniform in size, almost cylindrical; its sides still retain +a thin coating of pith, forming the reserves which the Osmia, as a +provident builder, has economized wherewith to construct the partitions. +So she scrapes away with her mandibles, keeping within a certain radius, +a radius that corresponds with the dimensions of the cell which she is +going to build next; moreover, she conducts her work in such a way as to +hollow out more in the middle and leave the two ends contracted. In this +manner, the cylindrical channel of the start is succeeded, in the worked +portion, by an ovoid cavity flattened at both ends, a space resembling a +little barrel. This space will form the second cell. + +As for the rubbish, it is utilized on the spot for the lid or cover +that serves as a ceiling for one cell and a floor for the next. Our own +master-builders could not contrive more successfully to make the best +use of their labourers' time. On the floor thus obtained, a second +ration of honey is placed; and an egg is laid on the surface of the +paste. Lastly, at the upper end of the little barrel, a partition is +built with the scrapings obtained in the course of the final work on the +third cell, which itself is shaped like a flattened ovoid. And so the +work goes on, cell upon cell, each supplying the materials for the +partition separating it from the one below. On reaching the end of the +cylinder, the Osmia closes up the case with a thick layer of the same +mortar. Then that bramble-stump is done with; the Bee will not return +to it. If her ovaries are not yet exhausted, other dry stems will be +exploited in the same fashion. + +The number of cells varies greatly, according to the qualities of the +stalk. If the bramble-stump be long, regular and smooth, we may count +as many as fifteen: that, at least, is the highest figure which my +observations have supplied. To obtain a good idea of the internal +distribution, we must split the stalk lengthwise, in the winter, when +the provisions have long been consumed and when the larvae are wrapped +in their cocoons. We then see that, at regular intervals, the case +becomes slightly narrower; and in each of the necks thus formed a +circular disk is fixed, a partition one or two millimetres thick. +(.039 to.079 inch.--Translator's Note.) The rooms separated by these +partitions form so many little barrels or kegs, each compactly filled +with a reddish, transparent cocoon, through which the larva shows, +bent into a fish-hook. The whole suggests a string of rough, oval amber +beads, touching at their amputated ends. + +In this string of cocoons, which is the oldest, which the youngest? The +oldest is obviously the bottom one, the one whose cell was the first +built; the youngest is the one at the top of the row, the one in the +cell last built. The oldest of the larvae starts the pile, down at the +bottom of the gallery; the latest arrival ends it at the top; and those +in between follow upon one another, according to age, from base to apex. + +Let us next observe that there is no room in the shaft for two Osmiae at +a time on the same level, for each cocoon fills up the storey, the keg +that belongs to it, without leaving any vacant space; let us also remark +that, when they attain the stage of perfection, the Osmiae must all +emerge from the shaft by the only orifice which the bramble-stem +boasts, the orifice at the top. There is here but one obstacle, easy +to overcome: a plug of glued pith, of which the insect's mandibles make +short work. Down below, the stalk offers no ready outlet; besides, it is +prolonged underground indefinitely by the roots. Everywhere else is the +ligneous fence, generally too hard and thick to break through. It is +inevitable therefore that all the Osmiae, when the time comes to quit +their dwelling, should go out by the top; and, as the narrowness of +the shaft bars the passage of the preceding insect as long as the next +insect, the one above it, remains in position, the removal must begin at +the top, extend from cell to cell and end at the bottom. Consequently, +the order of exit is the converse to the order of birth: the younger +Osmiae leave the nest first, their elders leave it last. + +The oldest, that is to say, the bottom one, was the first to finish her +supply of honey and to spin her cocoon. Taking precedence of all her +sisters in the whole series of her actions, she was the first to burst +her silken bag and to destroy the ceiling that closes her room: at +least, that is what the logic of the situation takes for granted. In +her anxiety to get out, how will she set about her release? The way +is blocked by the nearest cocoons, as yet intact. To clear herself a +passage through the string of those cocoons would mean to exterminate +the remainder of the brood; the deliverance of one would mean the +destruction of all the rest. Insects are notoriously obstinate in their +actions and unscrupulous in their methods. If the Bee at the bottom of +the shaft wants to leave her lodging, will she spare those who bar her +road? + +The difficulty is great, obviously; it seems insuperable. Thereupon we +become suspicious: we begin to wonder if the emergence from the cocoon, +that is to say, the hatching, really takes place in the order of +primogeniture. Might it not be--by a very singular exception, it +is true, but one which is necessary in such circumstances--that the +youngest of the Osmiae bursts her cocoon first and the oldest last; in +short, that the hatching proceeds from one chamber to the next in the +inverse direction to that which the age of the occupants would lead us +to presume? In that case, the whole difficulty would be removed: each +Osmia, as she rent her silken prison, would find a clear road in front +of her, the Osmiae nearer the outlet having gone out before her. But is +this really how things happen? Our theories very often do not agree with +the insect's practice; even where our reasoning seems most logical, +we should be more prudent to see what happens before venturing on any +positive statements. Leon Dufour was not so prudent when he, the first +in the field, took this little problem in hand. He describes to us the +habits of an Odynerus (Odynerus rubicola, DUF.) who piles up clay cells +in the shaft of a dry bramble-stalk; and, full of enthusiasm for his +industrious Wasp, he goes on to say: + +'Picture a string of eight cement shells, placed end to end and closely +wedged inside a wooden sheath. The lowest was undeniably made first and +consequently contains the first-laid egg, which, according to rules, +should give birth to the first winged insect. How do you imagine +that the larva in that first shell was bidden to waive its right of +primogeniture and only to complete its metamorphosis after all its +juniors? What are the conditions brought into play to produce a result +apparently so contrary to the laws of nature? Humble yourself in the +presence of the reality and confess your ignorance, rather than attempt +to hide your embarrassment under vain explanations! + +'If the first egg laid by the busy mother were destined to be the +first-born of the Odyneri, that one, in order to see the light +immediately after achieving wings, would have had the option either of +breaking through the double walls of his prison or of perforating, from +bottom to top, the seven shells ahead of him, in order to emerge through +the truncate end of the bramble-stem. Now nature, while refusing any +way of escape laterally, was also bound to veto any direct invasion, the +brutal gimlet-work which would inevitably have sacrificed seven members +of one family for the safety of an only son. Nature is as ingenious in +design as she is fertile in resource, and she must have foreseen and +forestalled every difficulty. She decided that the last-built cradle +should yield the first-born child; that this one should clear the road +for his next oldest brother, the second for the third and so on. And +this is the order in which the birth of our Odyneri of the Brambles +actually takes place.' + +Yes, my revered master, I will admit without hesitation that the +bramble-dwellers leave their sheath in the converse order to that of +their ages: the youngest first, the oldest last; if not invariably, at +least very often. But does the hatching, by which I mean the emergence +from the cocoon, take place in the same order? Does the evolution of +the elder wait upon that of the younger, so that each may give those who +would bar his passage time to effect their deliverance and to leave +the road clear? I very much fear that logic has carried your deductions +beyond the bounds of reality. Rationally speaking, my dear sir, nothing +could be more accurate than your inferences; and yet we must forgo +the theory of the strange inversion which you suggest. None of the +Bramble-bees with whom I have experimented behaves after that fashion. +I know nothing personal about Odynerus rubicola, who appears to be a +stranger in my district; but, as the method of leaving must be almost +the same when the habitation is exactly similar, it is enough, I think, +to experiment with some of the bramble-dwellers in order to learn the +history of the rest. + +My studies will, by preference, bear upon the Three-pronged Osmia, who +lends herself more readily to laboratory experiments, both because she +is stronger and because the same stalk will contain a goodly number of +her cells. The first fact to be ascertained is the order of hatching. +I take a glass tube, closed at one end, open at the other and of a +diameter similar to that of the Osmia's tunnel. In this I place, one +above the other, exactly in their natural order, the ten cocoons, or +thereabouts, which I extract from a stump of bramble. The operation is +performed in winter. The larvae, at that time, have long been enveloped +in their silken case. To separate the cocoons from one another, I employ +artificial partitions consisting of little round disks of sorghum, or +Indian millet, about half a centimetre thick. (About one-fifth of an +inch.--Translator's Note.) This is a white pith, divested of its fibrous +wrapper and easy for the Osmia's mandibles to attack. My diaphragms are +much thicker than the natural partitions; this is an advantage, as we +shall see. In any case, I could not well use thinner ones, for these +disks must be able to withstand the pressure of the rammer which places +them in position in the tube. On the other hand, the experiment showed +me that the Osmia makes short work of the material when it is a case of +drilling a hole through it. + +To keep out the light, which would disturb my insects destined to spend +their larval life in complete darkness, I cover the tube with a thick +paper sheath, easy to remove and replace when the time comes for +observation. Lastly, the tubes thus prepared and containing either +Osmiae or other bramble-dwellers are hung vertically, with the opening +at the top, in a snug corner of my study. Each of these appliances +fulfils the natural conditions pretty satisfactorily: the cocoons from +the same bramble-stick are stacked in the same order which they occupied +in the native shaft, the oldest at the bottom of the tube and the +youngest close to the orifice; they are isolated by means of partitions; +they are placed vertically, head upwards; moreover, my device has +the advantage of substituting for the opaque wall of the bramble a +transparent wall which will enable me to follow the hatching day by day, +at any moment which I think opportune. + +The male Osmia splits his cocoon at the end of June and the female at +the beginning of July. When this time comes, we must redouble our watch +and inspect the tubes several times a day if we would obtain exact +statistics of the births. Well, during the six years that I have studied +this question, I have seen and seen again, ad nauseam; and I am in a +position to declare that there is no order governing the sequence of +hatchings, absolutely none. The first cocoon to burst may be the one at +the bottom of the tube, the one at the top, the one in the middle or +in any other part, indifferently. The second to be split may adjoin the +first or it may be removed from it by a number of spaces, either above +or below. Sometimes several hatchings occur on the same day, within the +same hour, some farther back in the row of cells, some farther forward; +and this without any apparent reason for the simultaneity. In short, the +hatchings follow upon one another, I will not say haphazard--for each +of them has its appointed place in time, determined by impenetrable +causes--but at any rate contrary to our calculations, based on this or +the other consideration. + +Had we not been deceived by our too shallow logic, we might have +foreseen this result. The eggs are laid in their respective cells at +intervals of a few days, of a few hours. How can this slight difference +in age affect the total evolution, which lasts a year? Mathematical +accuracy has nothing to do with the case. Each germ, each grub has its +individual energy, determined we know not how and varying in each germ +or grub. This excess of vitality belongs to the egg before it leaves the +ovary. Might it not, at the moment of hatching, be the cause why this +or that larva takes precedence of its elders or its juniors, chronology +being altogether a secondary consideration? When the hen sits upon her +eggs, is the oldest always the first to hatch? In the same way, the +oldest larva, lodged in the bottom storey, need not necessarily reach +the perfect state first. + +A second argument, had we reflected more deeply on the matter, would +have shaken our faith in any strict mathematical sequence. The same +brood forming the string of cocoons in a bramble-stem contains +both males and females; and the two sexes are divided in the series +indiscriminately. Now it is the rule among the Bees for the males to +issue from the cocoon a little earlier than the females. In the case +of the Three-pronged Osmia, the male has about a week's start. +Consequently, in a populous gallery, there is always a certain number +of males, who are hatched seven or eight days before the females and who +are distributed here and there over the series. This would be enough to +make any regular hatching-sequence impossible in either direction. + +These surmises accord with the facts: the chronological sequence of +the cells tells us nothing about the chronological sequence of the +hatchings, which take place without any definite order. There is, +therefore, no surrender of rights of primogeniture, as Leon Dufour +thought: each insect, regardless of the others, bursts its cocoon when +its time comes; and this time is determined by causes which escape our +notice and which, no doubt, depend upon the potentialities of the egg +itself. It is the case with the other bramble-dwellers which I have +subjected to the same test (Osmia detrita, Anthidium scapulare, Solenius +vagus, etc.); and it must also be the case with Odynerus rubicola: so +the most striking analogies inform us. Therefore the singular exception +which made such an impression on Dufour's mind is a sheer logical +illusion. + +An error removed is tantamount to a truth gained; and yet, if it were +to end here, the result of my experiment would possess but slight value. +After destruction, let us turn to construction; and perhaps we shall +find the wherewithal to compensate us for an illusion lost. Let us begin +by watching the exit. + +The first Osmia to leave her cocoon, no matter what place she occupies +in the series, forthwith attacks the ceiling separating her from the +floor above. She cuts a fairly clean hole in it, shaped like a truncate +cone, having its larger base on the side where the Bee is and its +smaller base opposite. This conformation of the exit-door is a +characteristic of the work. When the insect tries to attack the +diaphragm, it first digs more or less at random; then, as the boring +progresses, the action is concentrated upon an area which narrows +until it presents no more than just the necessary passage. Nor is the +cone-shaped aperture special to the Osmia: I have seen it made by the +other bramble-dwellers through my thick disks of sorghum-pith. Under +natural conditions, the partitions, which, for that matter, are very +thin, are destroyed absolutely, for the contraction of the cell at +the top leaves barely the width which the insect needs. The truncate, +cone-shaped breach has often been of great use to me. Its wide base made +it possible for me, without being present at the work, to judge which +of the two neighbouring Osmiae had pierced the partition; it told me the +direction of a nocturnal migration which I had been unable to witness. + +The first-hatched Osmia, wherever she may be, has made a hole in her +ceiling. She is now in the presence of the next cocoon, with her head +at the opening of the hole. In front of her sister's cradle, she usually +stops, consumed with shyness; she draws back into her cell, flounders +among the shreds of the cocoon and the wreckage of the ruined ceiling; +she waits a day, two days, three days, more if necessary. Should +impatience gain the upper hand, she tries to slip between the wall of +the tunnel and the cocoon that blocks the way. She even undertakes the +laborious work of gnawing at the wall, so as to widen the interval, if +possible. We find these attempts, in the shaft of a bramble, at places +where the pith is removed down to the very wood, where the wood itself +is gnawed to some depth. I need hardly say that, although these lateral +inroads are perceptible after the event, they escape the eye at the +moment when they are being made. + +If we would witness them, we must slightly modify the glass apparatus. +I line the inside of the tube with a thick piece of whity-brown +packing-paper, but only over one half of the circumference; the other +half is left bare, so that I may watch the Osmia's attempts. Well, +the captive insect fiercely attacks this lining, which to its eyes +represents the pithy layer of its usual abode; it tears it away by tiny +particles and strives to cut itself a road between the cocoon and the +glass wall. The males, who are a little smaller, have a better chance of +success than the females. Flattening themselves, making themselves thin, +slightly spoiling the shape of the cocoon, which, however, thanks to +its elasticity, soon recovers its first condition, they slip through the +narrow passage and reach the next cell. The females, when in a hurry +to get out, do as much, if they find the tube at all amenable to the +process. But no sooner is the first partition passed than a second +presents itself. This is pierced in its turn. In the same way will the +third be pierced and others after that, if the insect can manage them, +as long as its strength holds out. Too weak for these repeated borings, +the males do not go far through my thick plugs. If they contrive to cut +through the first, it is as much as they can do; and, even so, they +are far from always succeeding. But, in the conditions presented by +the native stalk, they have only feeble tissues to overcome; and then, +slipping, as I have said, between the cocoon and the wall, which is +slightly worn owing to the circumstances described, they are able to +pass through the remaining occupied chambers and to reach the outside +first, whatever their original place in the stack of cells. It is just +possible that their early eclosion forces this method of exit upon them, +a method which, though often attempted, does not always succeed. The +females, furnished with stronger tools, make greater progress in my +tubes. I see some who pierce three or four partitions, one after the +other, and are so many stages ahead before those whom they have left +behind are even hatched. While they are engaged in this long and +toilsome operation, others, nearer to the orifice, have cleared a +passage whereof those from a distance will avail themselves. In this +way, it may happen that, when the width of the tube permits, an Osmia in +a back row will nevertheless be one of the first to emerge. + +In the bramble-stem, which is of exactly the same diameter as +the cocoon, this escape by the side of the column appears hardly +practicable, except to a few males; and even these have to find a wall +which has so much pith that by removing it they can effect a passage. +Let us then imagine a tube so narrow as to prevent any exit save in the +natural sequence of the cells. What will happen? A very simple thing. +The newly-hatched Osmia, after perforating his partition, finds himself +faced with an unbroken cocoon that obstructs the road. He makes a few +attempts upon the sides and, realizing his impotence, retires into his +cell, where he waits for days and days, until his neighbour bursts her +cocoon in her turn. His patience is inexhaustible. However, it is not +put to an over long test, for within a week, more or less, the whole +string of females is hatched. + +When two neighbouring Osmiae are released at the same time, mutual +visits are paid through the aperture between the two rooms: the one +above goes down to the floor below; the one below goes up to the floor +above; sometimes both of them are in the same cell together. Might not +this intercourse tend to cheer them and encourage them to patience? +Meanwhile, slowly, doors are opening here and there through the +separating walls; the road is cleared by sections; and a moment arrives +when the leader of the file walks out. The others follow, if ready; but +there are always laggards who keep the rear-ranks waiting until they are +gone. + +To sum up, first, the hatching of the larvae takes place without any +order; secondly, the exodus proceeds regularly from summit to base, but +only in consequence of the insect's inability to move forward so long +as the upper cells are not vacated. We have here not an exceptional +evolution, in the inverse ratio to age, but the simple impossibility of +emerging otherwise. Should a chance occur of going out before its turn, +the insect does not fail to seize it, as we can see by the lateral +movements which send the impatient ones a few ranks ahead and even +release the more favoured altogether. The only remarkable thing that +I perceive is the scrupulous respect shown to the as yet unopened +neighbouring cocoon. However eager to come out, the Osmia is most +careful not to touch it with his mandibles: it is taboo. He will +demolish the partition, he will gnaw the side-wall fiercely, even though +there be nothing left but wood, he will reduce everything around him to +dust; but touch a cocoon that obstructs his way? Never! He will not make +himself an outlet by breaking up his sisters' cradles. + +It may happen that the Osmia's patience is in vain and that the +barricade that blocks the way never disappears at all. Sometimes, the +egg in a cell does not mature; and the unconsumed provisions dry up and +become a compact, sticky, mildewed plug, through which the occupants +of the floors below could never clear themselves a passage. Sometimes, +again, a grub dies in its cocoon; and the cradle of the deceased, now +turned into a coffin, forms an everlasting obstacle. How shall the +insect cope with such grave circumstances? + +Among the many bramble-stumps which I have collected, some few have +presented a remarkable peculiarity. In addition to the orifice at the +top, they had at the side one and sometimes two round apertures that +looked as though they had been punched out with an instrument. On +opening these stalks, which were old, deserted nests, I discovered the +cause of these very exceptional windows. Above each of them was a cell +full of mouldy honey. The egg had perished and the provisions remained +untouched: hence the impossibility of getting out by the ordinary road. +Walled in by the unsurmountable obstacle, the Osmia on the floor below +had contrived an outlet through the side of the shaft; and those in the +lower storeys had benefited by this ingenious innovation. The usual +door being inaccessible, a side-window had been opened by means of the +insect's jaws. The cocoons, torn, but still in position in the lower +rooms, left no doubt as to this eccentric mode of exit. The same fact, +moreover, was repeated, in several bramble-stumps, in the case of Osmia +tridentata; it was likewise repeated in the case of Anthidium scapulare. +The observation was worth confirming by experiment. + +I select a bramble-stem with the thinnest rind possible, so as to +facilitate the Osmiae's work. I split it in half, thus obtaining a +smooth-sided trough which will enable me to judge better of future +exits. The cocoons are next laid out in one of the troughs. I separate +them with disks of sorghum, covering both surfaces of the disk with a +generous layer of sealing-wax, a material which the Osmia's mandibles +are not able to attack. The two troughs are then placed together and +fastened. A little putty does away with the joint and prevents the +least ray of light from penetrating. Lastly, the apparatus is hung up +perpendicularly, with the cocoons' heads up. We have now only to wait. +None of the Osmiae can get out in the usual manner, because each of them +is confined between two partitions coated with sealing-wax. There is but +one resource left to them if they would emerge into the light of day, +that is, for each of them to open a side-window, provided always that +they possess the instinct and the power to do so. + +In July, the result is as follows: of twenty Osmiae thus immured, six +succeed in boring a round hole through the wall and making their way +out; the others perish in their cells, without managing to release +themselves. But, when I open the cylinder, when I separate the two +wooden troughs, I realize that all have attempted to escape through the +side, for the wall of each cell bears traces of gnawing concentrated +upon one spot. All, therefore, have acted in the same way as their more +fortunate sisters; they did not succeed, because their strength failed +them. Lastly, in my glass tubes, part-lined with a thick piece of +packing-paper, I often see attempts at making a window in the side of +the cell: the paper is pierced right through with a round hole. + +This then is yet another result which I am glad to record in the history +of the bramble-dwellers. When the Osmia, the Anthidium and probably +others are unable to emerge through the customary outlet, they take +an heroic decision and perforate the side of the shaft. It is the last +resource, resolved upon after other methods have been tried in vain. The +brave, the strong succeed; the weak perish in the attempt. + +Supposing that all the Osmiae possessed the necessary strength of jaw as +well as the instinct for this sideward boring, it is clear that egress +from each cell through a special window would be much more advantageous +than egress through the common door. The Bee could attend to his release +as soon as he was hatched, instead of postponing it until after the +emancipation of those who come before him; he would thus escape long +waits, which too often prove fatal. In point of fact, it is no uncommon +thing to find bramble-stalks in which several Osmiae have died in their +cells, because the upper storeys were not vacated in time. Yes, there +would be a precious advantage in that lateral opening, which would not +leave each occupant at the mercy of his environment: many die that would +not die. All the Osmiae, when compelled by circumstances, resort to this +supreme method; all have the instinct for lateral boring; but very few +are able to carry the work through. Only the favourites of fate succeed, +those more generously endowed with strength and perseverance. + +If the famous law of natural selection, which is said to govern and +transform the world, had any sure foundation; if really the fittest +removed the less fit from the scene; if the future were to the +strongest, to the most industrious, surely the race of Osmiae, which +has been perforating bramble-stumps for ages, should by this time have +allowed its weaker members, who go on obstinately using the common +outlet, to die out and should have replaced them, down to the very last +one, by the stalwart drillers of side-openings. There is an opportunity +here for immense progress; the insect is on the verge of it and is +unable to cross the narrow intervening line. Selection has had ample +time to make its choice; and yet, though there be a few successes, the +failures exceed them in very large measure. The race of the strong has +not abolished the race of the weak: it remains inferior in numbers, +as doubtless it has been since all time. The law of natural selection +impresses me with the vastness of its scope; but, whenever I try to +apply it to actual facts, it leaves me whirling in space, with nothing +to help me to interpret realities. It is magnificent in theory, but it +is a mere gas-bubble in the face of existing conditions. It is majestic, +but sterile. Then where is the answer to the riddle of the world? Who +knows? Who will ever know? + +Let us waste no more time in this darkness, which idle theorizing will +not dispel; let us return to facts, humble facts, the only ground that +does not give way under our feet. The Osmia respects her neighbour's +cocoon; and her scruples are so great that, after vainly trying to slip +between that cocoon and the wall, or else to open a lateral outlet, she +lets herself die in her cell rather than effect an egress by forcing +her way through the occupied cells. When the cocoon that blocks the way +contains a dead instead of a live grub, will the result be the same? + +In my glass tubes, I let Osmia-cocoons containing a live grub alternate +with Osmia-cocoons in which the grub has been asphyxiated by the fumes +of sulphocarbonic acid. As usual, the storeys are separated by disks of +sorghum. The anchorites, when hatched, do not hesitate long. Once the +partition is pierced, they attack the dead cocoons, go right through +them, reducing the dead grub, now dry and shrivelled, to dust, and at +last emerge, after wrecking everything in their path. The dead cocoons, +therefore, are not spared; they are treated as would be any other +obstacle capable of attack by the mandibles. The Osmia looks upon them +as a mere barricade to be ruthlessly overturned. How is she apprised +that the cocoon, which has undergone no outward change, contains a dead +and not a live grub? It is certainly not by sight. Can it be by sense of +smell? I am always a little suspicious of that sense of smell of +which we do not know the seat and which we introduce on the slightest +provocation as a convenient explanation of that which may transcend our +explanatory powers. + +My next test is made with a string of live cocoons. Of course, I cannot +take all these from the same species, for then the experiment would not +differ from the one which we have already witnessed; I take them +from two different species which leave their bramble-stem at separate +periods. Moreover, these cocoons must have nearly the same diameter to +allow of their being stacked in a tube without leaving an empty space +between them and the wall. The two species adopted are Solenius vagus, +which quits the bramble at the end of June, and Osmia detrita, which +comes a little earlier, in the first fortnight of the same month. I +therefore alternate Osmia-cocoons and Solenius-cocoons, with the +latter at the top of the series, either in glass tubes or between two +bramble-troughs joined into a cylinder. + +The result of this promiscuity is striking. The Osmiae, which mature +earlier, emerge; and the Solenius-cocoons, as well as their inhabitants, +which by this time have reached the perfect stage, are reduced to +shreds, to dust, wherein it is impossible for me to recognize a vestige, +save perhaps here and there a head, of the exterminated unfortunates. +The Osmia, therefore, has not respected the live cocoons of a foreign +species: she has passed out over the bodies of the intervening Solenii. +Did I say passed over their bodies? She has passed through them, +crunched the laggards between her jaws, treated them as cavalierly as +she treats my disks. And yet those barricades were alive. No matter: +when her hour came, the Osmia went ahead, destroying everything upon +her road. Here, at any rate, is a law on which we can rely: the supreme +indifference of the animal to all that does not form part of itself and +its race. + +And what of the sense of smell, distinguishing the dead from the living? +Here, all are alive; and the Bee pierces her way as through a row of +corpses. If I am told that the smell of the Solenii may differ from that +of the Osmiae, I shall reply that such extreme subtlety in the insect's +olfactory apparatus seems to me a rather far-fetched supposition. Then +what is my explanation of the two facts? The explanation? I have none +to give! I am quite content to know that I do not know, which at least +spares me many vain lucubrations. And so I do not know how the Osmia, +in the dense darkness of her tunnel, distinguishes between a live cocoon +and a dead cocoon of the same species; and I know just as little how +she succeeds in recognizing a strange cocoon. Ah, how clearly this +confession of ignorance proves that I am behind the times! I am +deliberately missing a glorious opportunity of stringing big words +together and arriving at nothing. + +The bramble-stump is perpendicular, or nearly so; its opening is at the +top. This is the rule under natural conditions. My artifices are able +to alter that state of things; I can place the tube vertically or +horizontally; I can turn its one orifice either up or down; lastly, I +can leave the channel open at both ends, which will give two outlets. +What will happen under these several conditions? That is what we shall +examine with the Three-pronged Osmia. + +The tube is hung perpendicularly, but closed at the top and open at the +bottom; in fact, it represents a bramble-stump turned upside down. To +vary and complicate the experiment, the strings of cocoons are arranged +differently in different tubes. In some of them, the heads of the +cocoons are turned downwards, towards the opening; in others, they are +turned upwards, towards the closed end; in others again, the cocoons +alternate in direction, that is to say, they are placed head to head and +rear to rear, turn and turn about. I need not say that the separating +floors are of sorghum. + +The result is identical in all these tubes. If the Osmiae have their +heads pointing upwards, they attack the partition above them, as happens +under normal conditions; if their heads point downwards, they turn round +in their cells and set to work as usual. In short, the general outward +trend is towards the top, in whatever position the cocoon be placed. + +We here see manifestly at work the influence of gravity, which warns +the insect of its reversed position and makes it turn round, even as it +would warn us if we ourselves happened to be hanging head downwards. +In natural conditions, the insect has but to follow the counsels of +gravity, which tells it to dig upwards, and it will infallibly reach the +exit-door situated at the upper end. But, in my apparatus, these same +counsels betray it: it goes towards the top, where there is no outlet. +Thus misled by my artifices, the Osmiae perish, heaped up on the higher +floors and buried in the ruins. + +It nevertheless happens that attempts are made to clear a road +downwards. But it is rare for the work to lead to anything in this +direction, especially in the case of the middle or upper cells. The +insect is little inclined for this progress, the opposite to that to +which it is accustomed; besides, a serious difficulty arises in +the course of this reversed boring. As the Bee flings the excavated +materials behind her, these fall back of their own weight under +her mandibles; the clearance has to be begun anew. Exhausted by her +Sisyphean task, distrustful of this new and unfamiliar method, the Osmia +resigns herself and expires in her cell. I am bound to add, however, +that the Osmiae in the lower storeys, those nearest the exit--sometimes +one, sometimes two or three--do succeed in escaping. In that case, they +unhesitatingly attack the partitions below them, while their companions, +who form the great majority, persist and perish in the upper cells. + +It was easy to repeat the experiment without changing anything in the +natural conditions, except the direction of the cocoons: all that I had +to do was to hang up some bramble-stumps as I found them, vertically, +but with the opening downwards. Out of two stalks thus arranged and +peopled with Osmiae, not one of the insects succeeded in emerging. All +the Bees died in the shaft, some turned upwards, others downwards. +On the other hand, three stems occupied by Anthidia discharged their +population safe and sound. The outgoing was effected at the bottom, from +first to last, without the least impediment. Must we take it that +the two sorts of Bees are not equally sensitive to the influences of +gravity? Can the Anthidium, built to pass through the difficult obstacle +of her cotton wallets, be better-adapted than the Osmia to make her way +through the wreckage that keeps falling under the worker's feet; or, +rather, may not this very cotton-waste put a stop to these cataracts of +rubbish which must naturally drive the insect back? This is all quite +possible; but I can say nothing for certain. + +Let us now experiment with vertical tubes open at both ends. The +arrangements, save for the upper orifice, are the same as before. The +cocoons, in some of the tubes, have their heads turned down; others, +up; in others again, their positions alternate. The result is similar to +what we have seen above. A few Osmiae, those nearest the bottom orifice, +take the lower road, whatever the direction first occupied by the +cocoon; the others, composing by far the larger number, take the higher +road, even when the cocoon is placed upside down. As both doors are +free, the outgoing is effected at either end with success. + +What are we to conclude from all these experiments? First, that gravity +guides the insect towards the top, where the natural door is, and makes +it turn in its cell when the cocoon has been reversed. Secondly, I seem +to suspect an atmospheric influence and, in any case, some second cause +that sends the insect to the outlet. Let us admit that this cause is +the proximity of the outer air acting upon the anchorite through the +partitions. + +The animal then is subject, on the one hand, to the promptings of +gravity, and this to an equal degree for all, whatever the storey +inhabited. Gravity is the common guide of the whole series from base to +top. But those in the lower boxes have a second guide, when the bottom +end is open. This is the stimulus of the adjacent air, a more powerful +stimulus than that of gravity. The access of the air from without is +very slight, because of the partitions; while it can be felt in the +nethermost cells, it must decrease rapidly as the storeys ascend. +Wherefore the bottom insects, very few in number, obeying the +preponderant influence, that of the atmosphere, make for the lower +outlet and reverse, if necessary, their original position; those above, +on the contrary, who form the great majority, being guided only by +gravity when the upper end is closed, make for that upper end. It goes +without saying that, if the upper end be open at the same time as the +other, the occupants of the top storeys will have a double incentive to +take the ascending path, though this will not prevent the dwellers on +the lower floors from obeying, by preference, the call of the adjacent +air and adopting the downward road. + +I have one means left whereby to judge of the value of my explanation, +namely, to experiment with tubes open at both ends and lying +horizontally. The horizontal position has a twofold advantage. In +the first place, it removes the insect from the influence of gravity, +inasmuch as it leaves it indifferent to the direction to be taken, the +right or the left. In the second place, it does away with the descent +of the rubbish which, falling under the worker's feet when the boring is +done from below, sooner or later discourages her and makes her abandon +her enterprise. + +There are a few precautions to be observed for the successful conduct of +the experiment; I recommend them to any one who might care to make the +attempt. It is even advisable to remember them in the case of the tests +which I have already described. The males, those puny creatures, not +built for work, are sorry labourers when confronted with my stout disks. +Most of them perish miserably in their glass cells, without succeeding +in piercing their partitions right through. Moreover, instinct has been +less generous to them than to the females. Their corpses, interspersed +here and there in the series of the cells, are disturbing causes, +which it is wise to eliminate. I therefore choose the larger, more +powerful-looking cocoons. These, except for an occasional unavoidable +error, belong to females. I pack them in tubes, sometimes varying their +position in every way, sometimes giving them all a like arrangement. +It does not matter whether the whole series comes from one and the same +bramble-stump or from several: we are free to choose where we please; +the result will not be altered. + +The first time that I prepared one of these horizontal tubes open at +both ends, I was greatly struck by what happened. The series consisted +of ten cocoons. It was divided into two equal batches. The five on the +left went out on the left, the five on the right went out on the right, +reversing, when necessary, their original direction in the cell. It was +very remarkable from the point of view of symmetry; moreover, it was +a very unlikely arrangement among the total number of possible +arrangements, as mathematics will show us. + +Let us take n to represent the number of Osmiae. Each of them, once +gravity ceases to interfere and leaves the insect indifferent to either +end of the tube, is capable of two positions, according as she chooses +the exit on the right or on the left. With each of the two positions +of this first Osmia can be combined each of the two positions of the +second, giving us, in all, 2 x 2 = (2 squared) arrangements. Each of +these (2 squared) arrangements can be combined, in its turn, with each +of the two positions of the third Osmia. We thus obtain 2 x 2 x 2 = (2 +cubed) arrangements with three Osmiae; and so on, each additional +insect multiplying the previous result by the factor 2. With n Osmiae, +therefore, the total number of arrangements is (2 to the power n.) + +But note that these arrangements are symmetrical, two by two: a given +arrangement towards the right corresponds with a similar arrangement +towards the left; and this symmetry implies equality, for, in the +problem in hand, it is a matter of indifference whether a fixed +arrangement correspond with the right or left of the tube. The previous +number, therefore, must be divided by 2. Thus, n Osmiae, according as +each of them turns her head to the right or left in my horizontal tube, +are able to adopt (2 to the power n - 1) arrangements. If n = 10, as in +my first experiment, the number of arrangements becomes (2 to the power +9) = 512. + +Consequently, out of 512 ways which my ten insects can adopt for their +outgoing position, there resulted one of those in which the symmetry +was most striking. And observe that this was not an effect obtained by +repeated attempts, by haphazard experiments. Each Osmia in the left half +had bored to the left, without touching the partition on the right; each +Osmia in the right half had bored to the right, without touching +the partition on the left. The shape of the orifices and the surface +condition of the partition showed this, if proof were necessary. There +had been a spontaneous decision, one half in favour of the left, one +half in favour of the right. + +The arrangement presents another merit, one superior to that of +symmetry: it has the merit of corresponding with the minimum expenditure +of force. To admit of the exit of the whole series, if the string +consists of n cells, there are originally n partitions to be perforated. +There might even be one more, owing to a complication which I disregard. +There are, I say, at least n partitions to be perforated. Whether each +Osmia pierces her own, or whether the same Osmia pierces several, thus +relieving her neighbours, does not matter to us: the sum-total of the +force expended by the string of Bees will be in proportion to the number +of those partitions, in whatever manner the exit be effected. + +But there is another task which we must take seriously into +consideration, because it is often more troublesome than the boring of +the partition: I mean the work of clearing a road through the wreckage. +Let us suppose the partitions pierced and the several chambers blocked +by the resulting rubbish and by that rubbish only, since the horizontal +position precludes any mixing of the contents of different chambers. To +open a passage for itself through these rubbish-heaps, each insect +will have the smallest effort to make if it passes through the smallest +possible number of cells, in short, if it makes for the opening nearest +to it. These smallest individual efforts amount, in the aggregate, to +the smallest total effort. Therefore, by proceeding as they did in my +experiment, the Osmiae effect their exit with the least expenditure of +energy. It is curious to see an insect apply the 'principle of least +action,' so often postulated in mechanics. + +An arrangement which satisfies this principle, which conforms to the law +of symmetry and which possesses but one chance in 512, is certainly no +fortuitous result. It is determined by a cause; and, as this cause +acts invariably, the same arrangement must be reproduced if I renew the +experiment. I renewed it, therefore, in the years that followed, with as +many appliances as I could find bramble-stumps; and, at each new test, I +saw once more what I had seen with such interest on the first occasion. +If the number be even--and my column at that time consisted usually +of ten--one half goes out on the right, the other on the left. If the +number be odd--eleven, for instance--the Osmia in the middle goes out +indiscriminately by the right or left exit. As the number of cells to be +traversed is the same on both sides, her expenditure of energy does not +vary with the direction of the exit; and the principle of least action +is still observed. + +It was important to discover if the Three-pronged Osmia shared her +capacity, in the first place, with the other bramble-dwellers and, in +the second, with Bees differently housed, but also destined laboriously +to cut a new road for themselves when the hour comes to quit the nest. +Well, apart from a few irregularities, due either to cocoons whose +larva perished in my tubes before developing, or to those inexperienced +workers, the males, the result was the same in the case of Anthidium +scapulare. The insects divided themselves into two equal batches, one +going to the right, the other to the left. Tripoxylon figulus left +me undecided. This feeble insect is not capable of perforating my +partitions; it nibbles at them a little; and I had to judge the +direction from the marks of its mandibles. These marks, which are not +always very plain, do not yet allow me to pronounce an opinion. Solenius +vagus, who is a skilful borer, behaved differently from the Osmia. In a +column of ten, the whole exodus was made in one direction. + +On the other hand, I tested the Mason-bee of the Sheds, who, when +emerging under natural conditions, has only to pierce her cement ceiling +and is not confronted with a series of cells. Though a stranger to the +environment which I created for her, she gave me a most positive answer. +Of a column of ten laid in a horizontal tube open at both ends, five +made their way to the right and five to the left. Dioxys cincta, a +parasite in the buildings of both species of Mason-bees, the Chalicodoma +of the Sheds and the Chalicodoma of the Walls (Cf. "The Mason-bees" +by J. Henri Fabre, translated by Alexander Teixeira de Mattos: +passim.--Translator's Note.), provided me with no precise result. +The Leaf-cutting Bee (Megachile apicalis, SPIN. (Cf. Chapter 8 of the +present volume.--Translator's Note.)), who builds her leafy cups in the +old cells of the Chalicodoma of the Walls, acts like the Solenius and +directs her whole column towards the same outlet. + +Incomplete as it is, this symmetry shows us how unwise it were to +generalize from the conclusions to which the Three-pronged Osmia leads +us. Whereas some Bees, such as the Anthidium and the Chalicodoma, share +the Osmia's talent for using the twofold exit, others, such as the +Solenius and the Leaf-cutter, behave like a flock of sheep and follow +the first that goes out. The entomological world is not all of a piece; +its gifts are very various: what one is capable of doing another cannot +do; and penetrating indeed would be the eyes that saw the causes of +these differences. Be this as it may, increased research will certainly +show us a larger number of species qualified to use the double outlet. +For the moment, we know three; and that is enough for our purpose. + +I will add that, when the horizontal tube has one of its ends closed, +the whole string of Osmiae makes for the open end, turning round to do +so, if need be. + +Now that the facts are set forth, let us, if possible, trace the cause. +In a horizontal tube, gravity no longer acts to determine the direction +which the insect will take. Is it to attack the partition on the right +or that on the left? How shall it decide? The more I look into the +matter, the more do my suspicions fall upon the atmospheric influence +which is felt through the two open ends. Of what does this influence +consist? Is it an effect of pressure, of hygrometry, of electrical +conditions, of properties that escape our coarser physical attunement? +He were a bold man who should undertake to decide. Are not we ourselves, +when the weather is about to alter, subject to subtle impressions, +to sensations which we are unable to explain? And yet this vague +sensitiveness to atmospheric changes would not be of much help to us in +circumstances similar to those of my anchorites. Imagine ourselves in +the darkness and the silence of a prison-cell, preceded and followed +by other similar cells. We possess implements wherewith to pierce the +walls; but where are we to strike to reach the final outlet and to reach +it with the least delay? Atmospheric influence would certainly never +guide us. + +And yet it guides the insect. Feeble though it be, through the +multiplicity of partitions, it is exercised on one side more than on the +other, because the obstacles are fewer; and the insect, sensible to the +difference between those two uncertainties, unhesitatingly attacks the +partition which is nearer to the open air. Thus is decided the division +of the column into two converse sections, which accomplish the total +liberation with the least aggregate of work. In short, the Osmia and her +rivals 'feel' the free space. This is yet one more sensory faculty which +evolution might well have left us, for our greater advantage. As it has +not done so, are we then really, as many contend, the highest expression +of the progress accomplished, throughout the ages, by the first atom of +glair expanded into a cell? + + + + +CHAPTER 2. THE OSMIAE. + +February has its sunny days, heralding spring, to which rude winter will +reluctantly yield place. In snug corners, among the rocks, the great +spurge of our district, the characias of the Greeks, the jusclo of the +Provencals, begins to lift its drooping inflorescence and discreetly +opens a few sombre flowers. Here the first Midges of the year will come +to slake their thirst. By the time that the tip of the stalks reaches +the perpendicular, the worst of the cold weather will be over. + +Another eager one, the almond-tree, risking the loss of its fruit, +hastens to echo these preludes to the festival of the sun, preludes +which are too often treacherous. A few days of soft skies and it becomes +a glorious dome of white flowers, each twinkling with a roseate eye. +The country, which still lacks green, seems dotted everywhere with +white-satin pavilions. 'Twould be a callous heart indeed that could +resist the magic of this awakening. + +The insect nation is represented at these rites by a few of its more +zealous members. There is first of all the Honey-bee, the sworn enemy +of strikes, who profits by the least lull of winter to find out if some +rosemary is not beginning to open somewhere near the hive. The droning +of the busy swarm fills the flowery vault, while a snow of petals falls +softly to the foot of the tree. + +Together with the population of harvesters there mingles another, less +numerous, of mere drinkers, whose nesting-time has not yet begun. +This is the colony of the Osmiae, with their copper-coloured skin and +bright-red fleece. Two species have come hurrying up to take part in the +joys of the almond-tree: first, the Horned Osmia, clad in black velvet +on the head and breast and in red velvet on the abdomen; and, a little +later, the Three-horned Osmia, whose livery must be red and red only. +These are the first delegates despatched by the pollen-gleaners to +ascertain the state of the season and attend the festival of the early +blooms. 'Tis but a moment since they burst their cocoon, the winter +abode: they have left their retreats in the crevices of the old walls; +should the north wind blow and set the almond-tree shivering, they will +hasten to return to them. Hail to you, O my dear Osmiae, who yearly, +from the far end of the harmas (The piece of waste ground in which the +author studied his insects in their natural state. Cf. "The Life of +the Fly" by J. Henri Fabre, translated by Alexander Teixeira de Mattos: +chapter 1.--Translator's Note.), opposite snow-capped Ventoux (A +mountain in the Provencal Alps, near Carpentras and Serignan, 6,271 +feet.--Translator's Note.), bring me the first tidings of the awakening +of the insect world! I am one of your friends; let us talk about you a +little. + +Most of the Osmiae of my region have none of the industry of their +kinswomen of the brambles, that is to say, they do not themselves +prepare the dwelling destined for the laying. They want ready-made +lodgings, such as the old cells and old galleries of Anthophorae and +Chalicodomae. If these favourite haunts are lacking, then a hiding-place +in the wall, a round hole in some bit of wood, the tube of a reed, the +spiral of a dead Snail under a heap of stones are adopted, according to +the tastes of the several species. The retreat selected is divided into +chambers by partition-walls, after which the entrance to the dwelling +receives a massive seal. That is the sum-total of the building done. + +For this plasterer's rather than mason's work, the Horned and the +Three-horned Osmia employ soft earth. This material is different from +the Mason-bee's cement, which will withstand wind and weather for many +years on an exposed pebble; it is a sort of dried mud, which turns +to pap on the addition of a drop of water. The Mason-bee gathers her +cementing-dust in the most frequented and driest portions of the road; +she wets it with a saliva which, in drying, gives it the consistency of +stone. The two Osmiae who are the almond-tree's early visitors are +no chemists: they know nothing of the making and mixing of hydraulic +mortar; they limit themselves to gathering natural soaked earth, mud in +short, which they allow to dry without any special preparation on their +part; and so they need deep and well-sheltered retreats, into which the +rain cannot penetrate, or the work would fall to pieces. + +While exploiting, in friendly rivalry with the Three-horned Osmia, the +galleries which the Mason-bee of the Sheds good-naturedly surrenders to +both, Latreille's Osmia uses different materials for her partitions and +her doors. She chews the leaves of some mucilaginous plant, some mallow +perhaps, and then prepares a sort of green putty with which she builds +her partitions and finally closes the entrance to the dwelling. When +she settles in the spacious cells of the Masked Anthophora (Anthophora +personata, ILLIG.), the entrance to the gallery, which is wide enough to +admit one's finger, is closed with a voluminous plug of this vegetable +paste. On the earthy banks, hardened by the sun, the home is then +betrayed by the gaudy colour of the lid. It is as though the authorities +had closed the door and affixed to it their great seals of green wax. + +So far then as their building-materials are concerned, the Osmiae whom +I have been able to observe are divided into two classes: one building +compartments with mud, the other with a green-tinted vegetable putty. +The first section includes the Horned Osmia and the Three-horned Osmia, +both so remarkable for the horny tubercles on their faces. + +The great reed of the south, the Arundo donax, is often used, in the +country, for rough garden-shelters against the mistral or just for +fences. These reeds, the ends of which are chopped off to make them all +the same length, are planted perpendicularly in the earth. I have often +explored them in the hope of finding Osmia-nests. My search has very +seldom succeeded. The failure is easily explained. The partitions and +the closing-plug of the Horned and of the Three-horned Osmia are made, +as we have seen, of a sort of mud which water instantly reduces to pap. +With the upright position of the reeds, the stopper of the opening would +receive the rain and would become diluted; the ceilings of the storeys +would fall in and the family would perish by drowning. Therefore the +Osmia, who knew of these drawbacks before I did, refuses the reeds when +they are placed perpendicularly. + +The same reed is used for a second purpose. We make canisses of it, +that is to say, hurdles, which, in spring, serve for the rearing of +silk-worms and, in autumn, for the drying of figs. At the end of April +and during May, which is the time when the Osmiae work, the canisses +are indoors, in the silk-worm nurseries, where the Bee cannot take +possession of them; in autumn, they are outside, exposing their layers +of figs and peeled peaches to the sun; but by that time the Osmiae have +long disappeared. If, however, during the spring, an old, disused hurdle +is left out of doors, in a horizontal position, the Three-horned Osmia +often takes possession of it and makes use of the two ends, where the +reeds lie truncated and open. + +There are other quarters that suit the Three-horned Osmia, who is not +particular, it seems to me, and will make shift with any hiding-place, +so long as it has the requisite conditions of diameter, solidity, +sanitation and kindly darkness. The most original dwellings that I know +her to occupy are disused Snail-shells, especially the house of the +Common Snail (Helix aspersa). Let us go to the slope of the hills thick +with olive-trees and inspect the little supporting-walls which are +built of dry stones and face the south. In the crevices of this insecure +masonry, we shall reap a harvest of old Snail-shells, plugged with earth +right up to the orifice. The family of the Three-horned Osmia is settled +in the spiral of those shells, which is subdivided into chambers by mud +partitions. + +Let us inspect the stone-heaps, especially those which come from the +quarry-works. Here we often find the Field-mouse sitting on a grass +mattress, nibbling acorns, almonds, olive-stones and apricot-stones. The +Rodent varies his diet: to oily and farinaceous foods he adds the Snail. +When he is gone, he has left behind him, under the overhanging stones, +mixed up with the remains of other victuals, an assortment of empty +shells, sometimes plentiful enough to remind me of the heap of Snails +which, cooked with spinach and eaten country-fashion on Christmas Eve, +are flung away next day by the housewife. This gives the Three-horned +Osmia a handsome collection of tenements; and she does not fail to +profit by them. Then again, even if the Field-mouse's conchological +museum be lacking, the same broken stones serve as a refuge for +Garden-snails who come to live there and end by dying there. When we see +Three-horned Osmiae enter the crevices of old walls and of stone-heaps, +there is no doubt about their occupation: they are getting free lodgings +out of the old Snail-shells of those labyrinths. + +The Horned Osmia, who is less common, might easily also be less +ingenious, that is to say, less rich in varieties of houses. She seems +to scorn empty shells. The only homes that I know her to inhabit are the +reeds of the hurdles and the deserted cells of the Masked Anthophora. + +All the other Osmiae whose method of nest-building I know work with +green putty, a paste made of some crushed leaf or other; and none of +them, except Latreille's Osmia, is provided with the horned or tubercled +armour of the mud-kneaders. I should like to know what plants are used +in making the putty; probably each species has its own preferences and +its little professional secrets; but hitherto observation has taught me +nothing concerning these details. Whatever worker prepare it, the putty +is very much the same in appearance. When fresh, it is always a clear +dark green. Later, especially in the parts exposed to the air, it +changes, no doubt through fermentation, to the colour of dead leaves, +to brown, to dull-yellow; and the leafy character of its origin is no +longer apparent. But uniformity in the materials employed must not +lead us to believe in uniformity in the lodging; on the contrary, this +lodging varies greatly with the different species, though there is a +marked predilection in favour of empty shells. Thus Latreille's Osmia, +together with the Three-horned Osmia, uses the spacious structures +of the Mason-bee of the Sheds; she likes the magnificent cells of the +Masked Anthophora; and she is always ready to establish herself in the +cylinder of any reed lying flat on the ground. + +I have already spoken of an Osmia (O. cyanoxantha, PEREZ) who elects +to make her home in the old nests of the Mason-bee of the Pebbles. (Cf. +"The Mason-bees": chapter 10.--Translator's Note.) Her closing-plug is +made of a stout concrete, consisting of fair-sized bits of gravel +sunk in the green paste; but for the inner partitions she employs +only unalloyed putty. As the outer door, situated on the curve of an +unprotected dome, is exposed to the inclemencies of the weather, +the mother has to think of fortifying it. Danger, no doubt, is the +originator of that gritty concrete. + +The Golden Osmia (O. aurulenta, LATR.) absolutely insists on an empty +Snail-shell as her residence. The Brown or Girdled Snail, the Garden +Snail and especially the Common Snail, who has a more spacious spiral, +all scattered at random in the grass, at the foot of the walls and of +the sun-swept rocks, furnish her with her usual dwelling-house. Her +dried putty is a kind of felt full of short white hairs. It must come +from some hairy-leaved plant, one of the Boragineae perhaps, rich both +in mucilage and the necessary bristles. + +The Red Osmia (O. rufo-hirta, LATR.) has a weakness for the Brown Snail +and the Garden Snail, in whose shells I find her taking refuge in April +when the north-wind blows. I am not yet much acquainted with her work, +which should resemble that of the Golden Osmia. + +The Green Osmia (O. viridana, MORAWITZ) takes up her quarters, tiny +creature that she is, in the spiral staircase of Bulimulus radiatus. It +is a very elegant, but very small lodging, to say nothing of the fact +that a considerable portion is taken up with the green-putty plug. There +is just room for two. + +The Andrenoid Osmia (O. andrenoides, LATR.), who looks so curious, with +her naked red abdomen, appears to build her nest in the shell of the +Common Snail, where I discover her refuged. + +The Variegated Osmia (O. versicolor, LATR.) settles in the Garden +Snail's shell, almost right at the bottom of the spiral. + +The Blue Osmia (O. cyanea, KIRB.) seems to me to accept many different +quarters. I have extracted her from old nests of the Mason-bee of the +Pebbles, from the galleries dug in a roadside bank by the Colletes (A +short-tongued Burrowing-bee known also as the Melitta.--Translator's +Note.) and lastly from the cavities made by some digger or other in the +decayed trunk of a willow-tree. + +Morawitz' Osmia (O. Morawitzi, PEREZ) is not uncommon in the old nests +of the Mason-bee of the Pebbles, but I suspect her of favouring other +lodgings besides. + +The Three-pronged Osmia (O. tridentata, DUF. and PER.) creates a home of +her own, digging herself a channel with her mandibles in dry bramble and +sometimes in danewort. It mixes a few scrapings of perforated pith with +the green paste. Its habits are shared by the Ragged Osmia (O. detrita, +PEREZ) and by the Tiny Osmia (O. parvula, DUF.) + +The Chalicodoma works in broad daylight, on a tile, on a pebble, on a +branch in the hedge; none of her trade-practises is kept a secret from +the observer's curiosity. The Osmia loves mystery. She wants a dark +retreat, hidden from the eye. I would like, nevertheless, to watch +her in the privacy of her home and to witness her work with the same +facility as if she were nest-building in the open air. Perhaps there are +some interesting characteristics to be picked up in the depths of her +retreats. It remains to be seen whether my wish can be realized. + +When studying the insect's mental capacity, especially its very +retentive memory for places, I was led to ask myself whether it would +not be possible to make a suitably-chosen Bee build in any place that I +wished, even in my study. And I wanted, for an experiment of this sort, +not an individual but a numerous colony. My preference leant towards the +Three-horned Osmia, who is very plentiful in my neighbourhood, where, +together with Latreille's Osmia, she frequents in particular the +monstrous nests of the Chalicodoma of the Sheds. I therefore thought +out a scheme for making the Three-horned Osmia accept my study as her +settlement and build her nests in glass tubes, through which I could +easily watch the progress. To these crystal galleries, which might well +inspire a certain distrust, were to be added more natural retreats: +reeds of every length and thickness and disused Chalicodoma-cells taken +from among the biggest and the smallest. A scheme like this sounds mad. +I admit it, while mentioning that perhaps none ever succeeded so well +with me. We shall see as much presently. + +My method is extremely simple. All I ask is that the birth of my +insects, that is to say, their first seeing the light, their emerging +from the cocoon, should take place on the spot where I propose to make +them settle. Here there must be retreats of no matter what nature, +but of a shape similar to that in which the Osmia delights. The first +impressions of sight, which are the most long-lived of any, shall bring +back my insects to the place of their birth. And not only will the +Osmiae return, through the always open windows, but they will always +nidify on the natal spot if they find something like the necessary +conditions. + +And so, all through the winter, I collect Osmia-cocoons, picked up in +the nests of the Mason-bee of the Sheds; I go to Carpentras to glean a +more plentiful supply in the nests of the Hairy-footed Anthophora, that +old acquaintance whose wonderful cities I used to undermine when I +was studying the history of the Oil-beetles. (This study is not yet +translated into English; but cf. "The Life of the Fly": chapters 2 +and 4.--Translator's Note.) Later, at my request, a pupil and intimate +friend of mine, M. Henri Devillario, president of the civil court at +Carpentras, sends me a case of fragments broken off the banks frequented +by the Hairy-footed Anthophora and the Anthophora of the Walls, useful +clods which furnish a handsome adjunct to my collection. Indeed, at the +end, I find myself with handfuls of cocoons of the Three-horned Osmia. +To count them would weary my patience without serving any particular +purpose. + +I spread out my stock in a large open box on a table which receives +a bright diffused light but not the direct rays of the sun. The table +stands between two windows facing south and overlooking the garden. When +the moment of hatching comes, those two windows will always remain open +to give the swarm entire liberty to go in and out as it pleases. +The glass tubes and the reed-stumps are laid here and there, in fine +disorder, close to the heap of cocoons and all in a horizontal position, +for the Osmia will have nothing to do with upright reeds. The hatching +of some of the Osmiae will therefore take place under cover of the +galleries destined to be the building-yard later; and the site will be +all the more deeply impressed on their memory. When I have made these +comprehensive arrangements, there is nothing more to be done; and I wait +patiently for the building-season to open. + +My Osmiae leave their cocoons in the second half of April. Under the +immediate rays of the sun, in well-sheltered nooks, the hatching would +occur a month earlier, as we can see from the mixed population of +the snowy almond-tree. The constant shade in my study has delayed the +awakening, without, however, making any change in the nesting-period, +which synchronizes with the flowering of the thyme. We now have, around +my working-table, my books, my jars and my various appliances, a buzzing +crowd that goes in and out of the windows at every moment. I enjoin the +household henceforth not to touch a thing in the insects' laboratory, to +do no more sweeping, no more dusting. They might disturb the swarm and +make it think that my hospitality was not to be trusted. I suspect that +the maid, wounded in her self-esteem at seeing so much dust accumulating +in the master's study, did not always respect my prohibitions and came +in stealthily, now and again, to give a little sweep of the broom. +At any rate, I came across a number of Osmiae who seemed to have been +crushed under foot while taking a sunbath on the floor in front of the +window. Perhaps it was I myself who committed the misdeed in a heedless +moment. There is no great harm done, for the population is a numerous +one; and, notwithstanding those crushed by inadvertence, notwithstanding +the parasites wherewith many of the cocoons are infested, +notwithstanding those who may have come to grief outside or been unable +to find their way back, notwithstanding the deduction of one-half which +we must make for the males: notwithstanding all this, during four or +five weeks I witness the work of a number of Osmiae which is much too +large to allow of my watching their individual operations. I content +myself with a few, whom I mark with different-coloured spots to +distinguish them; and I take no notice of the others, whose finished +work will have my attention later. + +The first to appear are the males. If the sun is bright, they flutter +around the heap of tubes as if to take careful note of the locality; +blows are exchanged and the rival swains indulge in mild skirmishing +on the floor, then shake the dust off their wings and fly away. I find +them, opposite my window, in the refreshment-bar of the lilac-bush, +whose branches bend with the weight of their scented panicles. Here the +Bees get drunk with sunshine and draughts of honey. Those who have had +their fill come home and fly assiduously from tube to tube, placing +their heads in the orifices to see if some female will at last make up +her mind to emerge. + +One does, in point of fact. She is covered with dust and has the +disordered toilet that is inseparable from the hard work of the +deliverance. A lover has seen her, so has a second, likewise a third. +All crowd round her. The lady responds to their advances by clashing her +mandibles, which open and shut rapidly, several times in succession. The +suitors forthwith fall back; and they also, no doubt to keep up their +dignity, execute savage mandibular grimaces. Then the beauty retires +into the arbour and her wooers resume their places on the threshold. A +fresh appearance of the female, who repeats the play with her jaws; a +fresh retreat of the males, who do the best they can to flourish their +own pincers. The Osmiae have a strange way of declaring their passion: +with that fearsome gnashing of their mandibles, the lovers look as +though they meant to devour each other. It suggests the thumps affected +by our yokels in their moments of gallantry. + +The ingenious idyll is soon over. By turns greeting and greeted with a +clash of jaws, the female leaves her gallery and begins impassively to +polish her wings. The rivals rush forward, hoist themselves on top of +one another and form a pyramid of which each struggles to occupy the +base by toppling over the favoured lover. He, however, is careful not +to let go; he waits for the strife overhead to calm down; and, when the +supernumeraries realize that they are wasting their time and throw up +the game, the couple fly away far from the turbulent rivals. This is all +that I have been able to gather about the Osmia's nuptials. + +The females, who grow more numerous from day to day, inspect the +premises; they buzz outside the glass galleries and the reed dwellings; +they go in, stay for a while, come out, go in again and then fly away +briskly into the garden. They return, first one, then another. They halt +outside, in the sun, on the shutters fastened back against the wall; +they hover in the window-recess, come inside, go to the reeds and give a +glance at them, only to set off again and to return soon after. Thus +do they learn to know their home, thus do they fix their birthplace in +their memory. The village of our childhood is always a cherished spot, +never to be effaced from our recollection. The Osmia's life endures +for a month; and she acquires a lasting remembrance of her hamlet in +a couple of days. 'Twas there that she was born; 'twas there that she +loved; 'tis there that she will return. Dulces reminiscitur Argos. ('Now +falling by another's wound, his eyes He casts to heaven, on Argos thinks +and dies.'--"Aeneid," Book 10 Dryden's translation.) + +At last each has made her choice. The work of construction begins; and +my expectations are fulfilled far beyond my wishes. The Osmiae build +nests in all the retreats which I have placed at their disposal. The +glass tubes, which I cover with a sheet of paper to produce the shade +and mystery favourable to concentrated toil, do wonderfully well. All, +from first to last, are occupied. The Osmiae quarrel for the possession +of these crystal palaces, hitherto unknown to their race. The reeds +and the paper tubes likewise do wonderfully. The number provided is +too small; and I hasten to increase it. Snail-shells are recognized as +excellent abodes, though deprived of the shelter of the stone-heap; old +Chalicodoma-nests, down to those of the Chalicodoma of the Shrubs (Cf. +"The Mason-bees": chapters 4 and 10.--Translator's Note.), whose cells +are so small, are eagerly occupied. The late-comers, finding nothing +else free, go and settle in the locks of my table-drawers. There are +daring ones who make their way into half-open boxes containing ends of +glass tubes in which I have stored my most recent acquisitions: grubs, +pupae and cocoons of all kinds, whose evolution I wished to study. +Whenever these receptacles have an atom of free space, they claim the +right to build there, whereas I formally oppose the claim. I hardly +reckoned on such a success, which obliges me to put some order into +the invasion with which I am threatened. I seal up the locks, I shut my +boxes, I close my various receptacles for old nests, in short I remove +from the building-yard any retreat of which I do not approve. And now, O +my Osmiae, I leave you a free field! + +The work begins with a thorough spring-cleaning of the home. Remnants +of cocoons, dirt consisting of spoilt honey, bits of plaster from broken +partitions, remains of dried Mollusc at the bottom of a shell: these and +much other insanitary refuse must first of all disappear. Violently the +Osmia tugs at the offending object and tears it out; and then off she +goes, in a desperate hurry, to dispose of it far away from the study. +They are all alike, these ardent sweepers: in their excessive zeal, they +fear lest they should block up the place with a speck of dust which they +might drop in front of the new house. The glass tubes, which I myself +have rinsed under the tap, are not exempt from a scrupulous cleaning. +The Osmia dusts them, brushes them thoroughly with her tarsi and then +sweeps them out backwards. What does she pick up? Not a thing. It makes +no difference: as a conscientious housewife, she gives the place a touch +of the broom nevertheless. + +Now for the provisions and the partition-walls. Here the order of the +work changes according to the diameter of the cylinder. My glass tubes +vary greatly in dimensions. The largest have an inner width of a dozen +millimetres (Nearly half an inch.--Translator's Note.); the narrowest +measure six or seven. (About a quarter of an inch.--Translator's Note.) +In the latter, if the bottom suit her, the Osmia sets to work bringing +pollen and honey. If the bottom do not suit her, if the sorghum-pith +plug with which I have closed the rear-end of the tube be too irregular +and badly-joined, the Bee coats it with a little mortar. When this small +repair is made, the harvesting begins. + +In the wider tubes, the work proceeds quite differently. At the moment +when the Osmia disgorges her honey and especially at the moment when, +with her hind-tarsi, she rubs the pollen-dust from her ventral brush, +she needs a narrow aperture, just big enough to allow of her passage. +I imagine that, in a straitened gallery, the rubbing of her whole body +against the sides gives the harvester a support for her brushing-work. +In a spacious cylinder, this support fails her; and the Osmia starts +with creating one for herself, which she does by narrowing the channel. +Whether it be to facilitate the storing of the victuals or for any other +reason, the fact remains that the Osmia housed in a wide tube begins +with the partitioning. + +Her division is made by a dab of clay placed at right angles to the +axis of the cylinder, at a distance from the bottom determined by the +ordinary length of a cell. This wad is not a complete round; it is more +crescent-shaped, leaving a circular space between it and one side of the +tube. Fresh layers are swiftly added to the dab of clay; and soon the +tube is divided by a partition which has a circular opening at the side +of it, a sort of dog-hole through which the Osmia will proceed to knead +the Bee-bread. When the victualling is finished and the egg laid upon +the heap, the hole is closed and the filled-up partition becomes the +bottom of the next cell. Then the same method is repeated, that is to +say, in front of the just completed ceiling a second partition is built, +again with a side-passage, which is stouter, owing to its distance from +the centre, and better able to withstand the numerous comings and goings +of the housewife than a central orifice, deprived of the direct support +of the wall, could hope to be. When this partition is ready, the +provisioning of the second cell is effected; and so on until the wide +cylinder is completely stocked. + +The building of this preliminary party-wall, with a narrow, round +dog-hole, for a chamber to which the victuals will not be brought until +later is not restricted to the Three-horned Osmia; it is also frequently +found in the case of the Horned Osmia and of Latreille's Osmia. Nothing +could be prettier than the work of the last-named, who goes to the +plants for her material and fashions a delicate sheet in which she cuts +a graceful arch. The Chinaman partitions his house with paper screens; +Latreille's Osmia divides hers with disks of thin green cardboard +perforated with a serving-hatch which remains until the room is +completely furnished. When we have no glass houses at our disposal, +we can see these little architectural refinements in the reeds of the +hurdles, if we open them at the right season. + +By splitting the bramble-stumps in the course of July, we perceive +also that the Three-pronged Osmia, notwithstanding her narrow gallery, +follows the same practice as Latreille's Osmia, with a difference. She +does not build a party-wall, which the diameter of the cylinder would +not permit; she confines herself to putting up a frail circular pad of +green putty, as though to limit, before any attempt at harvesting, +the space to be occupied by the Bee-bread, whose depth could not be +calculated afterwards if the insect did not first mark out its confines. +Can there really be an act of measuring? That would be superlatively +clever. Let us consult the Three-horned Osmia in her glass tubes. + +The Osmia is working at her big partition, with her body outside the +cell which she is preparing. From time to time, with a pellet of mortar +in her mandibles, she goes in and touches the previous ceiling with +her forehead, while the tip of her abdomen quivers and feels the pad in +course of construction. One might well say that she is using the length +of her body as a measure, in order to fix the next ceiling at the +proper distance. Then she resumes her work. Perhaps the measure was +not correctly taken; perhaps her memory, a few seconds old, has already +become muddled. The Bee once more ceases laying her plaster and again +goes and touches the front wall with her forehead and the back wall with +the tip of her abdomen. Looking at that body trembling with eagerness, +extended to its full length to touch the two ends of the room, how can +we fail to grasp the architect's grave problem? The Osmia is measuring; +and her measure is her body. Has she quite done, this time? Oh dear +no! Ten times, twenty times, at every moment, for the least particle of +mortar which she lays, she repeats her mensuration, never being quite +certain that her trowel is going just where it should. + +Meanwhile, amid these frequent interruptions, the work progresses and +the partition gains in width. The worker is bent into a hook, with her +mandibles on the inner surface of the wall and the tip of her abdomen +on the outer surface. The soft masonry stands between the two points of +purchase. The insect thus forms a sort of rolling-press, in which the +mud wall is flattened and shaped. The mandibles tap and furnish mortar; +the end of the abdomen also pats and gives brisk trowel-touches. This +anal extremity is a builder's tool; I see it facing the mandibles on +the other side of the partition, kneading and smoothing it all over, +flattening the little lump of clay. It is a singular implement, which +I should never have expected to see used for this purpose. It takes an +insect to conceive such an original idea, to do mason's work with its +behind! During this curious performance, the only function of the legs +is to keep the worker steady by spreading out and clinging to the walls +of the tunnel. + +The partition with the hole in it is finished. Let us go back to the +measuring of which the Osmia was so lavish. What a magnificent argument +in favour of the reasoning-power of animals! To find geometry, the +surveyor's art, in an Osmia's tiny brain! An insect that begins by +taking the measurements of the room to be constructed, just as any +master-builder might do! Why, it's splendid, it's enough to cover with +confusion those horrible sceptics who persist in refusing to admit the +animal's 'continuous little flashes of atoms of reason!' + +O common-sense, veil your face! It is with this gibberish about +continuous flashes of atoms of reason that men pretend to build up +science to-day! Very well, my masters; the magnificent argument with +which I am supplying you lacks but one little detail, the merest trifle: +truth! Not that I have not seen and plainly seen all that I am relating; +but measuring has nothing to do with the case. And I can prove it by +facts. + +If, in order to see the Osmia's nest as a whole, we split a reed +lengthwise, taking care not to disturb its contents; or, better still, +if we select for examination the string of cells built in a glass tube, +we are forthwith struck by one detail, namely, the uneven distances +between the partitions, which are placed almost at right angles to the +axis of the cylinder. It is these distances which fix the size of +the chambers, which, with a similar base, have different heights and +consequently unequal holding-capacities. The bottom partitions, the +oldest, are farther apart; those of the front part, near the orifice, +are closer together. Moreover, the provisions are plentiful in the +loftier cells, whereas they are niggardly and reduced to one-half or +even one-third in the cells of lesser height. + +Here are a few examples of these inequalities. A glass tube with a +diameter of 12 millimetres (.468 inch.--Translator's Note.), inside +measurement, contains ten cells. The five lower ones, beginning with the +bottom-most, have as the respective distances between their partitions, +in millimetres: + +11, 12, 16, 13, 11. (.429,.468,.624,.507,.429 inch.--Translator's Note.) + +The five upper ones measure between their partitions: + +7, 7, 5, 6, 7. (.273,.273,.195,.234,.273 inch.--Translator's Note.) + +A reed-stump 11 millimetres (.429 inch.--Translator's Note.) across the +inside contains fifteen cells; and the respective distances between the +partitions of those cells, starting from the bottom, are: + +13, 12, 12, 9, 9, 11, 8, 8, 7, 7, 7, 6, 6, 6, 7. (.507,.468,.468, +.351,.351,.429,.312,.312,.273,.273,.273,.234,.234,.234, .273 +inch.--Translator's Note.) + +When the diameter of the tunnel is less, the partitions can be still +further apart, though they retain the general characteristic of being +closer to one another the nearer they are to the orifice. A reed of five +millimetres (.195 inch.--Translator's Note.) in diameter, gives me the +following distances, always starting from the bottom: + +22, 22, 20, 20, 12, 14. (.858,.858,.78,.78,.468,.546 inch.--Translator's +Note.) + +Another, of 9 millimetres (.351 inch.--Translator's Note.), gives me: + +15, 14, 11, 10, 10, 9, 10. (.585,.546,.429,.39,.39,.351,.39 +inch.--Translator's Note.) + +A glass tube of 8 millimetres (.312 inch.--Translator's Note.) yields: + +15, 14, 20, 10, 10, 10. (.585,.546,.78,.39,.39,.39 inch.--Translator's +Note.). + +I could fill pages and pages with such figures, if I cared to print all +my notes. Do they prove that the Osmia is a geometrician, employing a +strict measure based on the length of her body? Certainly not, because +many of those figures exceed the length of the insect; because sometimes +a higher number follows suddenly upon a lower; because the same string +contains a figure of one value and another figure of but half that +value. They prove only one thing: the marked tendency of the insect to +shorten the distance between the party-walls as the work proceeds. We +shall see later that the large cells are destined for the females and +the small ones for the males. + +Is there not at least a measuring adapted to each sex? Again, not so; +for in the first series, where the females are housed, instead of the +interval of 11 millimetres, which occurs at the beginning and the end, +we find, in the middle of the series, an interval of 16 millimetres, +while in the second series, reserved for the males, instead of the +interval of 7 millimetres at the beginning and the end, we have an +interval of 5 millimetres in the middle. It is the same with the other +series, each of which shows a striking discrepancy in its figures. If +the Osmia really studied the dimensions of her chambers and measured +them with the compasses of her body, how could she, with her delicate +mechanism, fail to notice mistakes of 5 millimetres, almost half her own +length? + +Besides, all idea of geometry vanishes if we consider the work in a tube +of moderate width. Here, the Osmia does not fix the front partition in +advance; she does not even lay its foundation. Without any boundary-pad, +with no guiding mark for the capacity of the cell, she busies herself +straightway with the provisioning. When the heap of Bee-bread is judged +sufficient, that is, I imagine, when her tired body tells her that she +has done enough harvesting, she closes up the chamber. In this case, +there is no measuring; and yet the capacity of the cell and the quantity +of the victuals fulfil the regular requirements of one or the other sex. + +Then what does the Osmia do when she repeatedly stops to touch the +front partition with her forehead and the back partition, the one in the +course of building, with the tip of her abdomen? I have no idea what +she does or what she has in view. I leave the interpretation of this +performance to others, more venturesome than I. Plenty of theories are +based on equally shaky foundations. Blow on them and they sink into the +quagmire of oblivion. + +The laying is finished, or perhaps the cylinder is full. A final +partition closes the last cell. A rampart is now built, at the orifice +of the tube itself, to forbid the ill-disposed all access to the home. +This is a thick plug, a massy work of fortification, whereon the Osmia +spends enough mortar to partition off any number of cells. A whole day +is not too long for making this barricade, especially in view of the +minute finishing-touches, when the Osmia fills up with putty every chink +through which the least atom could slip. The mason completing a wall +smooths his plaster and brings it to a fine surface while it is still +wet; the Osmia does the same, or almost. With little taps of the +mandibles and a continual shaking of her head, a sign of her zest for +the work, she smooths and polishes the surface of the lid for hours at a +time. After such pains, what foe could visit the dwelling? + +And yet there is one, an Anthrax, A. sinuata (Cf. "The Life of the Fly": +chapters 2 and 4.--Translator's Note.), who will come later on, in the +height of summer, and succeed, invisible bit of thread that she is, in +making her way to the grub through the thickness of the door and the web +of the cocoon. In many cells, mischief of another kind has already been +done. During the progress of the works, an impudent Midge, one of the +Tachina-flies, who feeds her family on the victuals amassed by the Bee, +hovers in front of the galleries. Does she penetrate to the cells and +lay her eggs there in the mother's absence? I could never catch the +sneak in the act. Does she, like that other Tachina who ravages cells +stocked with game (The cells of the Hunting Wasps.--Translator's Note.), +nimbly deposit her eggs on the Osmia's harvest at the moment when the +Bee is going indoors? It is possible, though I cannot say for certain. +The fact remains that we soon see the Midge's grub-worms swarming around +the larva, the daughter of the house. There are ten, fifteen, twenty or +more of them gnawing with their pointed mouths at the common dish and +turning the food into a heap of fine, orange-coloured vermicelli. The +Bee's grub dies of starvation. It is life, life in all its ferocity +even in these tiny creatures. What an expenditure of ardent labour, of +delicate cares, of wise precautions, to arrive at...what? Her offspring +sucked and drained dry by the hateful Anthrax; her family sweated and +starved by the infernal Tachina. + +The victuals consist mostly of yellow flour. In the centre of the heap, +a little honey is disgorged, which turns the pollen-dust into a firm, +reddish paste. On this paste the egg is laid, not flat, but upright, +with the fore-end free and the hind-end lightly held and fixed in the +plastic mass. When hatched, the young grub, kept in its place by its +rear-end, need only bend its neck a little to find the honey-soaked +paste under its mouth. When it grows stronger, it will release itself +from its support and eat up the surrounding flour. + +All this is touching, in its maternal logic. For the new-born, dainty +bread-and-honey; for the adolescent, dry bread. In cases where +the provisions are all of a kind, these delicate precautions are +superfluous. The victuals of the Anthophorae and the Chalicodomae +consist of flowing honey, the same throughout. The egg is then laid at +full length on the surface, without any particular arrangement, thus +compelling the new-born grub to take its first mouthfuls at random. This +has no drawback, as the food is of the same quality throughout. But, +with the Osmia's provisions--dry powder on the edges, jam in the +centre--the grub would be in danger if its first meal were not regulated +in advance. To begin with pollen not seasoned with honey would be +fatal to its stomach. Having no choice of its mouthfuls because of its +immobility and being obliged to feed on the spot where it was hatched, +the young grub must needs be born on the central mass, where it has only +to bend its head a little way in order to find what its delicate stomach +calls for. The place of the egg, therefore, fixed upright by its base in +the middle of the red jam, is most judiciously chosen. What a contrast +between this exquisite maternal forethought and the horrible destruction +by the Anthrax and the Midge! + +The egg is rather large for the size of the Osmia. It is cylindrical, +slightly curved, rounded at both ends and transparent. It soon becomes +cloudy, while remaining diaphanous at each extremity. Fine lines, hardly +perceptible to the most penetrating lens, show themselves in transverse +circles. These are the first signs of segmentation. A contraction +appears in the front hyaline part, marking the head. An extremely +thin opaque thread runs down either side. This is the cord of tracheae +communicating between one breathing-hole and another. At last, the +segments show distinctly, with their lateral pads. The grub is born. + +At first, one would think that there was no hatching in the proper sense +of the word--that is to say, no bursting and casting of a wrapper. +The most minute attention is necessary to show that appearances are +deceptive and that actually a fine membrane is thrown off from front to +back. This infinitesimal shred is the shell of the egg. + +The grub is born. Fixed by its base, it curves into an arc and bends its +head, until now held erect, down to the red mass. The meal begins. Soon +a yellow cord occupying the front two-thirds of the body proclaims that +the digestive apparatus is swelling out with food. For a fortnight, +consume your provender in peace, my child; then spin your cocoon: you +are now safe from the Tachina! Shall you be safe from the Anthrax' +sucker later on? Alack! + + + + +CHAPTER 3. THE DISTRIBUTION OF THE SEXES. + +Does the insect know beforehand the sex of the egg which it is about to +lay? When examining the stock of food in the cells just now, we began +to suspect that it does, for each little heap of provisions is carefully +proportioned to the needs at one time of a male and at another of a +female. What we have to do is to turn this suspicion into a certainty +demonstrated by experiment. And first let us find out how the sexes are +arranged. + +It is not possible to ascertain the chronological order of a laying, +except by going to suitably-chosen species. Digging up the burrows of +Cerceris-, Bembex- or Philanthus-wasps will never tell us that this grub +has taken precedence of that in point of time nor enable us to decide +whether one cocoon in a colony belongs to the same family as another. To +compile a register of births is absolutely impossible here. Fortunately +there are a few species in which we do not find this difficulty: these +are the Bees who keep to one gallery and build their cells in storeys. +Among the number are the different inhabitants of the bramble-stumps, +notably the Three-pronged Osmiae, who form an excellent subject for +observation, partly because they are of imposing-size--bigger than any +other bramble-dwellers in my neighbourhood--partly because they are so +plentiful. + +Let us briefly recall the Osmia's habits. Amid the tangle of a hedge, a +bramble-stalk is selected, still standing, but a mere withered stump. In +this the insect digs a more or less deep tunnel, an easy piece of work +owing to the abundance of soft pith. Provisions are heaped up right at +the bottom of the tunnel and an egg is laid on the surface of the +food: that is the first-born of the family. At a height of some twelve +millimetres (About half an inch.--Translator's Note.), a partition +is fixed, formed of bramble saw-dust and of a green paste obtained by +masticating particles of the leaves of some plant that has not yet +been identified. This gives a second storey, which in its turn receives +provisions and an egg, the second in order of primogeniture. And so it +goes on, storey by storey, until the cylinder is full. Then a thick plug +of the same green material of which the partitions are formed closes the +home and keeps out marauders. + +In this common cradle, the chronological order of births is perfectly +clear. The first-born of the family is at the bottom of the series; the +last-born is at the top, near the closed door. The others follow from +bottom to top in the same order in which they followed in point of +time. The laying is numbered automatically; each cocoon tells us its +respective age by the place which it occupies. + +To know the sexes, we must wait for the month of June. But it would be +unwise to postpone our investigations until that period. Osmia-nests are +not so common that we can hope to pick one up each time that we go out +with that object; besides, if we wait for the hatching-period before +examining the brambles, it may happen that the order has been disturbed +through some insects' having tried to make their escape as soon as +possible after bursting their cocoons; it may happen that the male +Osmiae, who are more forward than the females, are already gone. I +therefore set to work a long time beforehand and devote my leisure in +winter to these investigations. + +The bramble-sticks are split and the cocoons taken out one by one and +methodically transferred to glass tubes, of approximately the same +diameter as the native cylinder. These cocoons are arranged one on +top of the other in exactly the same order that they occupied in the +bramble; they are separated from one another by a cotton plug, an +insuperable obstacle to the future insect. There is thus no fear that +the contents of the cells may become mixed or transposed; and I am saved +the trouble of keeping a laborious watch. Each insect can hatch at its +own time, in my presence or not: I am sure of always finding it in +its place, in its proper order, held fast fore and aft by the cotton +barrier. A cork or sorghum-pith partition would not fulfil the same +purpose: the insect would perforate it and the register of births would +be muddled by changes of position. Any reader wishing to undertake +similar investigations will excuse these practical details, which may +facilitate his work. + +We do not often come upon complete series, comprising the whole laying, +from the first-born to the youngest. As a rule, we find part of a +laying, in which the number of cocoons varies greatly, sometimes falling +as low as two, or even one. The mother has not deemed it advisable to +confide her whole family to a single bramble-stump; in order to make the +exit less toilsome, or else for reasons which escape me, she has left +the first home and elected to make a second home, perhaps a third or +more. + +We also find series with breaks in them. Sometimes, in cells distributed +at random, the egg has not developed and the provisions have remained +untouched, but mildewed; sometimes, the larva has died before spinning +its cocoon, or after spinning it. Lastly, there are parasites, such +as the Unarmed Zonitis (Zonitis mutica, one of the +Oil-beetles.--Translator's Note.) and the Spotted Sapyga (A +Digger-wasp.--Translator's Note.), who interrupt the series by +substituting themselves for the original occupant. All these disturbing +factors make it necessary to examine a large number of nests of the +Three-pronged Osmia, if we would obtain a definite result. + +I have been studying the bramble-dwellers for seven or eight years and I +could not say how many strings of cocoons have passed through my hands. +During a recent winter, in view particularly of the distribution of the +sexes, I collected some forty of this Osmia's nests, transferred their +contents into glass tubes and made a careful summary of the sexes. +I give some of my results. The figures start in their order from the +bottom of the tunnel dug in the bramble and proceed upwards to the +orifice. The figure 1 therefore denotes the first-born of the series, +the oldest in date; the highest figure denotes the last-born. The letter +M, placed under the corresponding figure, represents the male and the +letter F the female sex. + +1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 F F M F M F M M F F F F M F M + +This is the longest series that I have ever been able to procure. It is +also complete, inasmuch as it comprises the entire laying of the Osmia. +My statement requires explaining, otherwise it would seem impossible to +know whether a mother whose acts one has not watched, nay more, whom +one has never seen, has or has not finished laying her eggs. The +bramble-stump under consideration leaves a free space of nearly four +inches above the continuous string of cocoons. Beyond it, at the actual +orifice, is the terminal stopper, the thick plug which closes the +entrance to the gallery. In this empty portion of the tunnel there is +ample accommodation for numerous cocoons. The fact that the mother has +not made use of it proves that her ovaries were exhausted; for it is +exceedingly unlikely that she has abandoned first-rate lodgings to +go laboriously digging a new gallery elsewhere and there continue her +laying. + +You may say that, if the unoccupied space marks the end of the laying, +nothing tells us that the beginning is actually at the bottom of the +cul-de-sac, at the other end of the tunnel. You may also say that the +laying is done in shifts, separated by intervals of rest. The space left +empty in the channel would mean that one of these shifts was finished +and not that there were no more eggs ripe for hatching. In answer +to these very plausible explanations, I will say that, the sum of my +observations--and they have been extremely numerous--is that the total +number of eggs laid not only by the Osmiae but by a host of other Bees +fluctuates round about fifteen. + +Besides, when we consider that the active life of these insects lasts +hardly a month; when we remember that this period of activity is +disturbed by dark, rainy or very windy days, during which all work is +suspended; when lastly we ascertain, as I have done ad nauseam in the +case of the Three-horned Osmia, the time required for building and +victualling a cell, it becomes obvious that the total laying must be +kept within narrow bounds and that the mother has no time to lose if she +wishes to get fifteen cells satisfactorily built in three or four weeks +interrupted by compulsory rests. I shall give some facts later which +will dispel your doubts, if any remain. + +I assume, therefore, that a number of eggs bordering on fifteen +represents the entire family of an Osmia, as it does of many other Bees. + +Let us consult some other complete series. Here are two: + +1 2 3 4 5 6 7 8 9 10 11 12 13 F F M F M F M F F F F M F F M F F F M F F +M F M + +In both cases, the laying is taken as complete, for the same reasons as +above. + +We will end with some series that appear to me incomplete, in view of +the small number of cells and the absence of any free space above the +pile of cocoons: + +1 2 3 4 5 6 7 8 M M F M M M M M M M F M F M M M F M F F M M M M M F M F +F F F M M M F M + +These examples are more than sufficient. It is quite evident that the +distribution of the sexes is not governed by any rule. All that I can +say on consulting the whole of my notes, which contain a good many +instances of complete layings--most of them, unfortunately, spoilt +through gaps caused by parasites, the death of the larva, the failure of +the egg to hatch and other accidents--all that I can say in general is +that the complete series begins with females and nearly always ends with +males. The incomplete series can teach us nothing in this respect, +for they are only fragments starting we know not whence; and it is +impossible to tell whether they should be ascribed to the beginning, to +the end, or to an intermediate period of the laying. To sum up: in the +laying of the Three-pronged Osmia, no order governs the succession of +the sexes; only, the series has a marked tendency to begin with females +and to finish with males. + +The brambles, in my district, harbour two other Osmiae, both of much +smaller size: O. detrita, PEREZ, and O. parvula, DUF. The first is very +common, the second very rare; and until now I have found only one of +her nests, placed above a nest of O. detrita, in the same bramble. Here, +instead of the lack of order in the distribution of the sexes which we +find with O. tridentata, we have an order remarkable for consistency +and simplicity. I have before me the list of the series of O. detrita +collected last winter. Here are some of them: + +1. A series of twelve: seven females, beginning with the bottom of the +tunnel, and then five males. + +2. A series of nine: three females first, then six males. + +3. A series of eight: five females followed by three males. + +4. A series of eight: seven females followed by one male. + +5. A series of eight: one female followed by seven males. + +6. A series of seven: six females followed by one male. + +The first series might very well be complete. The second and fifth +appear to be the end of layings, of which the beginning has taken place +elsewhere, in another bramble-stump. The males predominate and finish +off the series. Nos. 3, 4 and 6, on the other hand, look like the +beginnings of layings: the females predominate and are at the head of +the series. Even if these interpretations should be open to doubt, one +result at least is certain: with O. detrita, the laying is divided into +two groups, with no intermingling of the sexes; the first group laid +yields nothing but females, the second, or more recent, yields nothing +but males. + +What was only a sort of attempt with the Three-pronged Osmia--who, it is +true, begins with females and ends with males, but muddles up the order +and mixes the two sexes anyhow between the extreme points--becomes a +regular law with her kinswoman. The mother occupies herself at the start +with the stronger sex, the more necessary, the better-gifted, the female +sex, to which she devotes the first flush of her laying and the fullness +of her vigour; later, when she is perhaps already at the end of her +strength, she bestows what remains of her maternal solicitude upon the +weaker sex, the less-gifted, almost negligible male sex. + +O. parvula, of whom I unfortunately possess but one series, repeats +what the previous witness has just shown us. This series, one of nine +cocoons, comprises five females followed by four males, without any +mixing of the sexes. + +Next to these disgorgers of honey and gleaners of pollen-dust, it would +be well to consult other Hymenoptera, Wasps who devote themselves to the +chase and pile their cells one after the other, in a row, showing +the relative age of the cocoons. The brambles house several of these: +Solenius vagus, who stores up Flies; Psen atratus, who provides her +grubs with a heap of Plant-lice; Trypoxylon figulus, who feeds them with +Spiders. + +Solenius vagus digs her gallery in a bramble-stick that is lopped short, +but still fresh and green. The house of this Fly-huntress, therefore, +suffers from damp, as the sap enters, especially on the lower floors. +This seems to me rather insanitary. To avoid the humidity, or for other +reasons which escape me, the Solenius does not dig very far into her +bramble-stump and consequently can stack but a small number of cells in +it. A series of five cocoons gives me first four females and then one +male; another series, also of five, contains first three females, with +two males following. These are the most complete that I have for the +moment. + +I reckoned on the Black Psen, or Psen atratus, whose series are pretty +long; it is a pity that they are nearly always greatly interfered with +by a parasite called Ephialtes mediator. (Cf. "The Life of the Fly": +chapter 2.--Translator's Note.) I obtained only three series free +from gaps: one of eight cocoons, comprising only females; one of six, +likewise consisting wholly of females; lastly, one of eight, formed +exclusively of males. These instances seem to show that the Psen +arranges her laying in a succession of females and a succession of +males; but they tell us nothing of the relative order of the two series. + +From the Spider-huntress, Trypoxylon figulus, I learnt nothing +decisive. She appeared to me to rove about from one bramble to the next, +utilizing galleries which she has not dug herself. Not troubling to be +economical with a lodging which it has cost her nothing to acquire, she +carelessly builds a few partitions at very unequal heights, stuffs +three or four compartments with Spiders and passes on to another +bramble-stump, with no reason, so far as I know, for abandoning the +first. Her cells, therefore, occur in series that are too short to give +us any useful information. + +This is all that the bramble-dwellers have to tell us; I have enumerated +the list of the principal ones in my district. We will now look +into some other Bees who arrange their cocoons in single files: the +Megachiles (Cf. Chapter 8 of the present volume.--Translator's Note.), +who cut disks out of leaves and fashion the disks into thimble-shaped +receptacles; the Anthidia (Cf. Chapters 9 and 10 of the present +volume.--Translator's Note.), who weave their honey-wallets out +of cotton-wool and arrange their cells one after the other in some +cylindrical gallery. In most cases, the home is the produce of neither +the one nor the other. A tunnel in the upright, earthy banks, the old +work of some Anthophora, is the usual dwelling. There is no great depth +to these retreats; and all my searches, zealously prosecuted during a +number of winters, procured me only series containing a small number of +cocoons, four or five at most, often one alone. And, what is quite as +serious, nearly all these series are spoilt by parasites and allow me to +draw no well-founded deductions. + +I remembered finding, at rare intervals, nests of both the Anthidium and +the Megachile in the hollows of cut reeds. I thereupon installed +some hives of a new kind on the sunniest walls of my enclosure. They +consisted of stumps of the great reed of the south, open at one end, +closed at the other by the natural knot and gathered into a sort +of enormous pan-pipe, such as Polyphemus might have employed. The +invitation was accepted: Osmiae, Anthidia and Megachiles came in +fairly large numbers, especially the first, to benefit by the queer +installation. + +In this way I obtained some magnificent series of Anthidia and +Megachiles, running up to a dozen. There was a melancholy side to +this success. All my series, with not one exception, were ravaged by +parasites. Those of the Megachile (M. sericans, FONSCOL), who fashions +her goblets with robinia-, holm-, and terebinth-leaves, were inhabited +by Coelioxys octodentata (A Parasitic Bee.--Translator's Note.); those +of the Anthidium (A. florentinum, LATR.) were occupied by a Leucopsis. +Both kinds were swarming with a colony of pigmy parasites whose name I +have not yet been able to discover. In short, my pan-pipe hives, though +very useful to me from other points of view, taught me nothing about the +order of the sexes among the Leaf-cutters and the cotton-weavers. + +I was more fortunate with three Osmiae (O. tricornis, LATR., O. cornuta, +LATR., and O. Latreillii, SPIN.), all of whom gave me splendid results, +with reed-stumps arranged either against the walls of my garden, as I +have just said, or near their customary abode, the huge nests of the +Mason-bee of the Sheds. One of them, the Three-horned Osmia, did +better still: as I have described, she built her nests in my study, as +plentifully as I could wish, using reeds, glass tubes and other retreats +of my selecting for her galleries. + +We will consult this last, who has furnished me with documents beyond +my fondest hopes, and begin by asking her of how many eggs her average +laying consists. Of the whole heap of colonized tubes in my study, or +else out of doors, in the hurdle-reeds and the pan-pipe appliances, the +best-filled contains fifteen cells, with a free space above the series, +a space showing that the laying is ended, for, if the mother had any +more eggs available, she would have lodged them in the room which she +leaves unoccupied. This string of fifteen appears to be rare; it was the +only one that I found. My attempts at indoor rearing, pursued during two +years with glass tubes or reeds, taught me that the Three-horned +Osmia is not much addicted to long series. As though to decrease the +difficulties of the coming deliverance, she prefers short galleries, in +which only a part of the laying is stacked. We must then follow the same +mother in her migration from one dwelling to the next if we would obtain +a complete census of her family. A spot of colour, dropped on the Bee's +thorax with a paint-brush while she is absorbed in closing up the mouth +of the tunnel, enables us to recognize the Osmia in her various homes. + +In this way, the swarm that resided in my study furnished me, in the +first year, with an average of twelve cells. Next year, the summer +appeared to be more favourable and the average became rather higher, +reaching fifteen. The most numerous laying performed under my eyes, not +in a tube, but in a succession of Snail-shells, reached the figure of +twenty-six. On the other hand, layings of between eight and ten are not +uncommon. Lastly, taking all my records together, the result is that the +family of the Osmia fluctuates round about fifteen in number. + +I have already spoken of the great differences in size apparent in +the cells of one and the same series. The partitions, at first widely +spaced, draw gradually nearer to one another as they come closer to +the aperture, which implies roomy cells at the back and narrow cells in +front. The contents of these compartments are no less uneven between one +portion and another of the string. Without any exception known to me, +the large cells, those with which the series starts, have more abundant +provisions than the straitened cells with which the series ends. The +heap of honey and pollen in the first is twice or even thrice as large +as that in the second. In the last cells, the most recent in date, +the victuals are but a pinch of pollen, so niggardly in amount that we +wonder what will become of the larva with that meagre ration. + +One would think that the Osmia, when nearing the end of the laying, +attaches no importance to her last-born, to whom she doles out space +and food so sparingly. The first-born receive the benefit of her +early enthusiasm: theirs is the well-spread table, theirs the spacious +apartments. The work has begun to pall by the time that the last eggs +are laid; and the last-comers have to put up with a scurvy portion of +food and a tiny corner. + +The difference shows itself in another way after the cocoons are spun. +The large cells, those at the back, receive the bulky cocoons; the small +ones, those in front, have cocoons only a half or a third as big. Before +opening them and ascertaining the sex of the Osmia inside, let us wait +for the transformation into the perfect insect, which will take place +towards the end of summer. If impatience gets the better of us, we can +open them at the end of July or in August. The insect is then in the +nymphal stage; and it is easy, under this form, to distinguish the two +sexes by the length of the antennae, which are larger in the males, +and by the glassy protuberances on the forehead, the sign of the future +armour of the females. Well, the small cocoons, those in the narrow +front cells, with their scanty store of provisions, all belong to males; +the big cocoons, those in the spacious and well-stocked cells at the +back, all belong to females. + +The conclusion is definite: the laying of the Three-horned Osmia +consists of two distinct groups, first a group of females and then a +group of males. + +With my pan-pipe apparatus displayed on the walls of my enclosure and +with old hurdle-reeds left lying flat out of doors, I obtained the +Horned Osmia in fair quantities. I persuaded Latreille's Osmia to +build her nest in reeds, which she did with a zeal which I was far from +expecting. All that I had to do was to lay some reed-stumps horizontally +within her reach, in the immediate neighbourhood of her usual haunts, +namely, the nests of the Mason-bee of the Sheds. Lastly, I succeeded +without difficulty in making her build her nests in the privacy of my +study, with glass tubes for a house. The result surpassed my hopes. + +With both these Osmiae, the division of the gallery is the same as +with the Three-horned Osmia. At the back are large cells with plentiful +provisions and widely-spaced partitions; in front, small cells, with +scanty provisions and partitions close together. Also, the larger cells +supplied me with big cocoons and females; the smaller cells gave me +little cocoons and males. The conclusion therefore is exactly the same +in the case of all three Osmiae. + +Before dismissing the Osmiae, let us devote a moment to their cocoons, a +comparison of which, in the matter of bulk, will furnish us with fairly +accurate evidence as to the relative size of the two sexes, for the +thing contained, the perfect insect, is evidently proportionate to the +silken wrapper in which it is enclosed. These cocoons are oval-shaped +and may be regarded as ellipsoids formed by a revolution around the +major axis. The volume of one of these solids is expressed in the +following formula: + +4 / 3 x pi x a x (b squared), + +in which 2a is the major axis and 2b the minor axis. + +Now, the average dimensions of the cocoons of the Three-horned Osmia are +as follows: + +2a = 13 mm. (.507 inch.--Translator's Note.), 2b = 7 mm. (.273 +inch.--Translator's Note.) in the females; + +2a = 9 mm. (.351 inch.--Translator's Note.), 2b = 5 mm. (.195 +inch.--Translator's Note.) in the males. + +The ratio therefore between 13 x 7 x 7 = 637 and 9 x 5 x 5 = 225 will be +more or less the ratio between the sizes of the two sexes. This ratio +is somewhere between 2 to 1 and 3 to 1. The females therefore are two or +three times larger than the males, a proportion already suggested by a +comparison of the mass of provisions, estimated simply by the eye. + +The Horned Osmia gives us the following average dimensions: + +2a = 15 mm. (.585 inch.--Translator's Note.), 2b = 9 mm. (.351 +inch.--Translator's Note.) in the females; + +2a = 12 mm. (.468 inch.--Translator's Note.), 2b = 7 mm. (.273 +inch.--Translator's Note.) in the males. + +Once again, the ratio between 15 x 9 x 9 = 1215 and 12 x 7 x 7 = 588 +lies between 2 to 1 and 3 to 1. + +Besides the Bees who arrange their laying in a row, I have consulted +others whose cells are grouped in a way that makes it possible to +ascertain the relative order of the two sexes, though not quite so +precisely. One of these is the Mason-bee of the Walls. I need not +describe again her dome-shaped nest, built on a pebble, which is now so +well-known to us. (Cf. "The Mason-bees": chapter 1.--Translator's Note.) + +Each mother chooses her stone and works on it in solitude. She is an +ungracious landowner and guards her site jealously, driving away any +Mason who even looks as though she might alight on it. The inhabitants +of the same nest are therefore always brothers and sisters; they are the +family of one mother. + +Moreover, if the stone presents a large enough surface--a condition +easily fulfilled--the Mason-bee has no reason to leave the support +on which she began her laying and go in search of another whereon to +deposit the rest of her eggs. She is too thrifty of her time and of her +mortar to involve herself in such expenditure except for grave reasons. +Consequently, each nest, at least when it is new, when the Bee herself +has laid the first foundations, contains the entire laying. It is a +different thing when an old nest is restored and made into a place for +depositing the eggs. I shall come back later to such houses. + +A newly-built nest then, with rare exceptions, contains the entire +laying of one female. Count the cells and we shall have the total list +of the family. Their maximum number fluctuates round about fifteen. +The most luxuriant series will occasionally reach as many as eighteen, +though these are very scarce. + +When the surface of the stone is regular all around the site of the +first cell, when the mason can add to her building with the same +facility in every direction, it is obvious that the groups of cells, +when finished, will have the oldest in the central portion and the more +recent in the surrounding portion. Because of this juxtaposition of +the cells, which serve partly as a wall to those which come next, it is +possible to form some estimate of the chronological order of the cells +in the Chalicodoma's nest and thus to discover the sequence of the two +sexes. + +In winter, by which time the Bee has long been in the perfect state, I +collect Chalicodoma-nests, removing them bodily from their support with +a few smart sideward taps of the hammer on the pebbles. At the base of +the mortar dome the cells are wide agape and display their contents. I +take the cocoon from its box, open it and take note of the sex of the +insect enclosed. + +I should probably be accused of exaggeration if I mentioned the total +number of the nests which I have gathered and the cells which I have +inspected by this method during the last six or seven years. I will +content myself with saying that the harvest of a single morning +sometimes consisted of as many as sixty nests of the Mason-bee. I had to +have help in carrying home my spoils, even though the nests were removed +from their stones on the spot. + +From the enormous number of nests which I have examined, I am able to +state that, when the cluster is regular, the female cells occupy the +centre and the male cells the edges. Where the irregularity of the +pebble has prevented an even distribution around the initial point, the +same rule has been observed. A male cell is never surrounded on every +side by female cells: either it occupies the edges of the nest, or else +it adjoins, at least on some sides, other male cells, of which the last +form part of the exterior of the cluster. As the surrounding cells are +obviously of a later date than the inner cells, it follows that the +Mason-bee acts like the Osmiae: she begins her laying with females +and ends it with males, each of the sexes forming a series of its own, +independent of the other. + +Some further circumstances add their testimony to that of the surrounded +and surrounding cells. When the pebble projects sharply and forms a sort +of dihedral angle, one of whose faces is more or less vertical and the +other horizontal, this angle is a favourite site with the Mason, who +thus finds greater stability for her edifice in the support given her by +the double plane. These sites appear to me to be in great request with +the Chalicodoma, considering the number of nests which I find thus +doubly supported. In nests of this kind, all the cells, as usual, have +their foundations fixed to the horizontal surface; but the first row, +the row of cells first built, stands with its back against the vertical +surface. + +Well, these older cells, which occupy the actual edge of the dihedral +angle, are always female, with the exception of those at either end of +the row, which, as they belong to the outside, may be male cells. In +front of this first row come others. The female cells occupy the middle +portion and the male the ends. Finally, the last row, closing in the +remainder, contains only male cells. The progress of the work is very +visible here: the Mason has begun by attending to the central group of +female cells, the first row of which occupies the dihedral angle, and +has finished her task by distributing the male cells round the outside. + +If the perpendicular face of the dihedral angle be high enough, it +sometimes happens that a second row of cells is placed above the first +row backing on to that plane; a third row occurs less often. The nest is +then one of several storeys. The lower storeys, the older, contain only +females; the upper, the more recent storey, contains none but males. It +goes without saying that the surface layer, even of the lower storeys, +can contain males without invalidating the rule, for this layer may +always be looked upon as the Chalicodoma's last work. + +Everything therefore contributes to show that, in the Mason-bee, the +females take the lead in the order of primogeniture. Theirs is the +central and best-protected part of the clay fortress; the outer part, +that most exposed to the inclemencies of the weather and to accidents, +is for the males. + +The males' cells do not differ from the females' only by being placed at +the outside of the cluster; they differ also in their capacity, which is +much smaller. To estimate the respective capacities of the two sorts +of cells, I go to work as follows: I fill the empty cell with very fine +sand and pour this sand back into a glass tube measuring 5 millimetres +(.195 inch.--Translator's Note.) in diameter. From the height of the +column of sand we can estimate the comparative capacity of the two kinds +of cells. I will take one at random among my numerous examples of cells +thus gauged. + +It comprises thirteen cells and occupies a dihedral angle. The female +cells give me the following figures, in millimetres, as the height of +the columns of sand: + +40, 44, 43, 48, 48, 46, 47 (1.56, 1.71, 1.67, 1.87, 1.87, 1.79, 1.83 +inches.--Translator's Note.), + +averaging 45. (1.75 inches.--Translator's Note.) + +The male cells give me: + +32, 35, 28, 30, 30, 31 (1.24, 1.36, 1.09, 1.17, 1.17, 1.21 +inches.--Translator's Note.), + +averaging 31. (1.21 inches.--Translator's Note.) + +The ratio of the capacity of the cells for the two sexes is therefore +roughly a ratio of 4 to 3. The actual contents of the cell being +proportionate to its capacity, the above ratio must also be more or +less the ratio of provisions and sizes between females and males. These +figures will assist us presently to tell whether an old cell, occupied +for a second or third time, belonged originally to a female or a male. + +The Chalicodoma of the Sheds cannot give us any information on this +matter. She builds under the same eaves, in excessively populous +colonies; and it is impossible to follow the labours of any single +Mason, whose cells, distributed here and there, are soon covered up +with the work of her neighbours. All is muddle and confusion in the +individual output of the swarming throng. + +I have not watched the work of the Chalicodoma of the Shrubs with close +enough attention to be able to state definitely that this Bee is a +solitary builder. Her nest is a ball of clay hanging from a bough. +Sometimes, this nest is the size of a large walnut and then appears to +be the work of one alone; sometimes, it is the size of a man's fist, in +which case I have no doubt that it is the work of several. Those bulky +nests, comprising more than fifty cells, can tell us nothing exact, as a +number of workers must certainly have collaborated to produce them. + +The walnut-sized nests are more trustworthy, for everything seems to +indicate that they were built by a single Bee. Here females are found +in the centre of the group and males at the circumference, in somewhat +smaller cells, thus repeating what the Mason-bee of the Pebbles has told +us. + +One clear and simple rule stands out from this collection of facts. +Apart from the strange exception of the Three-pronged Osmia, who mixes +the sexes without any order, the Bees whom I studied and probably a +crowd of others produce first a continuous series of females and then a +continuous series of males, the latter with less provisions and smaller +cells. This distribution of the sexes agrees with what we have long +known of the Hive-bee, who begins her laying with a long sequence of +workers, or sterile females, and ends it with a long sequence of +males. The analogy continues down to the capacity of the cells and the +quantities of provisions. The real females, the Queen-bees, have wax +cells incomparably more spacious than the cells of the males and receive +a much larger amount of food. Everything therefore demonstrates that we +are here in the presence of a general rule. + +But does this rule express the whole truth? Is there nothing beyond a +laying in two series? Are the Osmiae, the Chalicodomae and the rest of +them fatally bound by this distribution of the sexes into two distinct +groups, the male group following upon the female group, without any +mixing of the two? Is the mother absolutely powerless to make a change +in this arrangement, should circumstances require it? + +The Three-pronged Osmia already shows us that the problem is far from +being solved. In the same bramble-stump, the two sexes occur very +irregularly, as though at random. Why this mixture in the series +of cocoons of a Bee closely related to the Horned Osmia and the +Three-horned Osmia, who stack theirs methodically by separate sexes +in the hollow of a reed? What the Bee of the brambles does cannot her +kinswomen of the reeds do too? Nothing, so far as I know, can explain +this difference in a physiological act of primary importance. The three +Bees belong to the same genus; they resemble one another in general +outline, internal structure and habits; and, with this close similarity, +we suddenly find a strange dissimilarity. + +There is just one thing that might possibly arouse a suspicion of the +cause of this irregularity in the Three-pronged Osmia's laying. If I +open a bramble-stump in the winter to examine the Osmia's nest, I find +it impossible, in the vast majority of cases, to distinguish positively +between a female and a male cocoon: the difference in size is so +small. The cells, moreover, have the same capacity: the diameter of the +cylinder is the same throughout and the partitions are almost always the +same distance apart. If I open it in July, the victualling-period, it is +impossible for me to distinguish between the provisions destined for the +males and those destined for the females. The measurement of the column +of honey gives practically the same depth in all the cells. We find an +equal quantity of space and food for both sexes. + +This result makes us foresee what a direct examination of the two sexes +in the adult form tells us. The male does not differ materially from +the female in respect of size. If he is a trifle smaller, it is scarcely +noticeable, whereas, in the Horned Osmia and the Three-horned Osmia, +the male is only half or a third the size of the female, as we have seen +from the respective bulk of their cocoons. In the Mason-bee of the Walls +there is also a difference in size, though less pronounced. + +The Three-pronged Osmia has not therefore to trouble about adjusting the +dimensions of the dwelling and the quantity of the food to the sex of +the egg which she is about to lay; the measure is the same from one end +of the series to the other. It does not matter if the sexes alternate +without order: one and all will find what they need, whatever their +position in the row. The two other Osmiae, with their great disparity +in size between the two sexes, have to be careful about the twofold +consideration of board and lodging. And that, I think, is why they begin +with spacious cells and generous rations for the homes of the females +and end with narrow, scantily-provisioned cells, the homes of the males. +With this sequence, sharply defined for the two sexes, there is less +fear of mistakes which might give to one what belongs to another. If +this is not the explanation of the facts, I see no other. + +The more I thought about this curious question, the more probable it +appeared to me that the irregular series of the Three-pronged Osmia and +the regular series of the other Osmiae, of the Chalicodomae and of the +Bees in general were all traceable to a common law. It seemed to me that +the arrangement in a succession first of females and then of males did +not account for everything. There must be something more. And I was +right: that arrangement in series is only a tiny fraction of the +reality, which is remarkable in a very different way. This is what I am +going to prove by experiment. + + + + +CHAPTER 4. THE MOTHER DECIDES THE SEX OF THE EGG. + +I will begin with the Mason-bee of the Pebbles. (This is the same +insect as the Mason-bee of the Walls. Cf. "The Mason-bees": +passim.--Translator's Note.) The old nests are often used, when they are +in good enough repair. Early in the season the mothers quarrel fiercely +over them; and, when one of the Bees has taken possession of the coveted +dome, she drives any stranger away from it. The old house is far from +being a ruin, only it is perforated with as many holes as it once had +occupants. The work of restoration is no great matter. The heap of earth +due to the destruction of the lid by the outgoing tenant is taken out of +the cell and flung away at a distance, atom by atom. The remnants of +the cocoon are also thrown away, but not always, for the delicate silken +wrapper sometimes adheres closely to the masonry. + +The victualling of the renovated cell is now begun. Next comes the +laying; and lastly the orifice is sealed with a mortar plug. A second +cell is utilized in the same way, followed by a third and so on, one +after the other, as long as any remain unoccupied and the mother's +ovaries are not exhausted. Finally, the dome receives, mainly over the +apertures already plugged, a coat of plaster which makes the nest look +like new. If she has not finished her laying, the mother goes in search +of other old nests to complete it. Perhaps she does not decide to found +a new establishment except when she can find no second-hand dwellings, +which mean a great economy of time and labour. In short, among the +countless number of nests which I have collected, I find many more +ancient than recent ones. + +How shall we distinguish one from the other? The outward aspect tells +you nothing, owing to the great care taken by the Mason to restore the +surface of the old dwelling equal to new. To resist the rigours of the +winter, this surface must be impregnable. The mother knows that and +therefore repairs the dome. Inside, it is another matter: the old nest +stands revealed at once. There are cells whose provisions, at least a +year old, are intact, but dried up or musty, because the egg has never +developed. There are others containing a dead larva, reduced by time +to a blackened, curled-up cylinder. There are some whence the perfect +insect was never able to issue: the Chalicodoma wore herself out in +trying to pierce the ceiling of her chamber; her strength failed her and +she perished in the attempt. Others again and very many are occupied +by ravagers, Leucopses (Cf. "The Mason-bees": chapter 11.--Translator's +Note.) and Anthrax-flies, who will come out a good deal later, in July. +Altogether, the house is far from having every room vacant; there are +nearly always a considerable number occupied either by parasites that +were still in the egg-stage at the time when the Mason-bee was at work +or by damaged provisions, dried grubs or Chalicodomae in the perfect +state who have died without being able to effect their deliverance. + +Should all the rooms be available, a rare occurrence, there still +remains a method of distinguishing between an ancient nest and a recent +one. The cocoon, as I have said, adheres pretty closely to the walls; +and the mother does not always take away this remnant, either +because she is unable to do so, or because she considers the removal +unnecessary. Thus the base of the new cocoon is set in the bottom of the +old cocoon. This double wrapper points very clearly to two generations, +two separate years. I have even found as many as three cocoons fitting +one into another at their bases. Consequently, the nests of the +Mason-bee of the Pebbles are able to do duty for three years, if not +more. Eventually they become utter ruins, abandoned to the Spiders and +to various smaller Bees or Wasps, who take up their quarters in the +crumbling rooms. + +As we see, an old nest is hardly ever capable of containing the +Mason-bee's entire laying, which calls for some fifteen apartments. The +number of rooms at her disposal is most unequal, but always very small. +It is saying much when there are enough to receive about half the +laying. Four or five cells, sometimes two or even one: that is what +the Mason usually finds in a nest that is not her own work. This large +reduction is explained when we remember the numerous parasites that live +upon the unfortunate Bee. + +Now, how are the sexes distributed in those layings which are +necessarily broken up between one old nest and another? They are +distributed in such a way as utterly to upset the idea of an invariable +succession first of females and then of males, the idea which occurs +to us on examining the new nests. If this rule were a constant one, we +should be bound to find in the old domes at one time only females, at +another only males, according as the laying was at its first or at its +second stage. The simultaneous presence of the two sexes would then +correspond with the transition period between one stage and the next and +should be very unusual. On the contrary, it is very common; and, however +few cells there may be, we always find both females and males in the old +nests, on the sole condition that the compartments have the regulation +holding-capacity, a large capacity for the females, a lesser for the +males, as we have seen. + +The old male cells can be recognized by their position on the outer +edges and by their capacity, measuring on an average the same as a +column of sand 31 millimetres high in a glass tube 5 millimetres wide. +(1.21 x.195 inches.--Translator's Note.) These cells contain males of +the second or third generation and none but males. In the old female +cells, those in the middle, whose capacity is measured by a similar +column of sand 45 millimetres high (1.75 inches.--Translator's Note.), +are females and none but females. + +This presence of both sexes at a time, even when there are but two cells +free, one spacious and the other small, proves in the plainest fashion +that the regular distribution observed in the complete nests of recent +production is here replaced by an irregular distribution, harmonizing +with the number and holding-capacity of the chambers to be stocked. The +Mason-bee has before her, let me suppose, only five vacant cells: two +larger and three smaller. The total space at her disposal would do for +about a third of the laying. Well, in the two large cells, she puts +females; in the three small cells, she puts males. + +As we find the same sort of thing in all the old nests, we must needs +admit that the mother knows the sex of the egg which she is going to +lay, because that egg is placed in a cell of the proper capacity. We can +go further and admit that the mother alters the order of succession of +the sexes at her pleasure, because her layings, between one old nest and +another, are broken up into small groups of males and females according +to the exigencies of space in the actual nest which she happens to be +occupying. + +Just now, in the new nest, we saw the Mason-bee arranging her total +laying into series first of females and next of males; and here she +is, mistress of an old nest of which she has not the power to alter the +arrangement, breaking up her laying into sections comprising both sexes +just as required by the conditions imposed upon her. She therefore +decides the sex of the egg at will, for, without this prerogative, she +could not, in the chambers of the nest which she owes to chance, deposit +unerringly the sex for which those chambers were originally built; and +this happens however small the number of chambers to be filled. + +When the nest is new, I think I see a reason why the Mason-bee +should seriate her laying into females and then males. Her nest is +a half-sphere. That of the Mason-bee of the Shrubs is very nearly a +sphere. Of all shapes, the spherical shape is the strongest. Now these +two nests require an exceptional power of resistance. Without protection +of any kind, they have to brave the weather, one on its pebble, the +other on its bough. Their spherical configuration is therefore very +practical. + +The nest of the Mason-bee of the Walls consists of a cluster of upright +cells backing against one another. For the whole to take a spherical +form, the height of the chambers must diminish from the centre of the +dome to the circumference. Their elevation is the sine of the meridian +arc starting from the plane of the pebble. Therefore, if they are to +have any solidity, there must be large cells in the middle and small +cells at the edges. And, as the work begins with the central chambers +and ends with those on the circumference, the laying of the females, +destined for the large cells, must precede that of the males, destined +for the small cells. So the females come first and the males at the +finish. + +This is all very well when the mother herself founds the dwelling, when +she lays the first rows of bricks. But, when she is in the presence +of an old nest, of which she is quite unable to alter the general +arrangement, how is she to make use of the few vacant rooms, the large +and the small alike, if the sex of the egg be already irrevocably fixed? +She can only do so by abandoning the arrangement in two consecutive +rows and accommodating her laying to the varied exigencies of the home. +Either she finds it impossible to make an economical use of the old +nest, a theory refuted by the evidence, or else she determines at will +the sex of the egg which she is about to lay. + +The Osmiae themselves will furnish the most conclusive evidence on the +latter point. We have seen that these Bees are not generally miners, who +themselves dig out the foundation of their cells. They make use of the +old structures of others, or else of natural retreats, such as hollow +stems, the spirals of empty shells and various hiding-places in walls, +clay or wood. Their work is confined to repairs to the house, such +as partitions and covers. There are plenty of these retreats; and the +insect would always find first-class ones if it thought of going any +distance to look for them. But the Osmia is a stay-at-home: she returns +to her birth-place and clings to it with a patience extremely difficult +to exhaust. It is here, in this little familiar corner, that she prefers +to settle her progeny. But then the apartments are few in number and of +all shapes and sizes. There are long and short ones, spacious ones and +narrow. Short of expatriating herself, a Spartan course, she has to use +them all, from first to last, for she has no choice. Guided by these +considerations, I embarked on the experiments which I will now describe. + +I have said how my study, on two separate occasions, became a populous +hive, in which the Three-horned Osmia built her nests in the various +appliances which I had prepared for her. Among these appliances, tubes, +either of glass or reed, predominated. There were tubes of all lengths +and widths. In the long tubes, entire or almost entire layings, with a +series of females followed by a series of males, were deposited. As I +have already referred to this result, I will not discuss it again. The +short tubes were sufficiently varied in length to lodge one or other +portion of the total laying. Basing my calculations on the respective +lengths of the cocoons of the two sexes, on the thickness of the +partitions and the final lid, I shortened some of these to the exact +dimensions required for two cocoons only, of different sexes. + +Well, these short tubes, whether of glass or reed, were seized upon as +eagerly as the long tubes. Moreover, they yielded this splendid result: +their contents, only a part of the total laying, always began with +female and ended with male cocoons. This order was invariable; what +varied was the number of cells in the long tubes and the proportion +between the two sorts of cocoons, sometimes males predominating and +sometimes females. + +The experiment is of paramount importance; and it will perhaps make the +result clearer if I quote one instance from among a multitude of similar +cases. I give the preference to this particular instance because of +the rather exceptional fertility of the laying. An Osmia marked on the +thorax is watched, day by day, from the commencement to the end of her +work. From the 1st to the 10th of May, she occupies a glass tube in +which she lodges seven females followed by a male, which ends the +series. From the 10th to the 17th of May, she colonizes a second tube, +in which she lodges first three females and then three males. From the +17th to the 25th of May, a third tube, with three females and then two +males. On the 26th of May, a fourth tube, which she abandons, probably +because of its excessive width, after laying one female in it. Lastly, +from the 26th to the 30th of May, a fifth tube, which she colonizes +with two females and three males. Total: twenty-five Osmiae, including +seventeen females and eight males. And it will not be superfluous to +observe that these unfinished series do not in any way correspond with +periods separated by intervals of rest. The laying is continuous, in so +far as the variable condition of the atmosphere allows. As soon as one +tube is full and closed, another is occupied by the Osmia without delay. + +The tubes reduced to the exact length of two cells fulfilled my +expectation in the great majority of cases: the lower cell was occupied +by a female and the upper by a male. There were a few exceptions. +More discerning than I in her estimate of what was strictly necessary, +better-versed in the economy of space, the Osmia had found a way of +lodging two females where I had only seen room for one female and a +male. + +This experiment speaks volumes. When confronted with tubes too small to +receive all her family, she is in the same plight as the Mason-bee +in the presence of an old nest. She thereupon acts exactly as the +Chalicodoma does. She breaks up her laying, divides it into series as +short as the room at her disposal demands; and each series begins with +females and ends with males. This breaking up, on the one hand, into +sections in all of which both sexes are represented and the division, on +the other hand, of the entire laying into just two groups, one female, +the other male, when the length of the tube permits, surely provide us +with ample evidence of the insect's power to regulate the sex of the egg +according to the exigencies of space. + +And besides the exigencies of space one might perhaps venture to add +those connected with the earlier development of the males. These burst +their cocoons a couple of weeks or more before the females; they are the +first who hasten to the sweets of the almond-tree. In order to release +themselves and emerge into the glad sunlight without disturbing the +string of cocoons wherein their sisters are still sleeping, they must +occupy the upper end of the row; and this, no doubt, is the reason that +makes the Osmia end each of her broken layings with males. Being next to +the door, these impatient ones will leave the home without upsetting the +shells that are slower in hatching. + +I experimented on Latreille's Osmia, using short and even very short +stumps of reed. All that I had to do was to lay them just beside the +nests of the Mason-bee of the Sheds, nests beloved by this particular +Osmia. Old, disused hurdles supplied me with reeds inhabited from end to +end by the Horned Osmia. In both cases I obtained the same results and +the same conclusions as with the Three-horned Osmia. + +I return to the latter, nidifying under my eyes in some old nests of the +Mason-bee of the Walls, which I had placed within her reach, mixed up +with the tubes. Outside my study, I had never yet seen the Three-horned +Osmia adopt that domicile. This may be due to the fact that these nests +are isolated one by one in the fields; and the Osmia, who loves to feel +herself surrounded by her kin and to work in plenty of company, refuses +them because of this isolation. But on my table, finding them close +to the tubes in which the others are working, she adopts them without +hesitation. + +The chambers presented by those old nests are more or less spacious +according to the thickness of the coat of mortar which the Chalicodoma +has laid over the assembled chambers. To leave her cell, the Mason-bee +has to perforate not only the plug, the lid built at the mouth of the +cell, but also the thick plaster wherewith the dome is strengthened at +the end of the work. The perforation results in a vestibule which gives +access to the chamber itself. It is this vestibule which is sometimes +longer and sometimes shorter, whereas the corresponding chamber is of +almost constant dimensions, in the case of the same sex, of course. + +We will first consider the short vestibule, at the most large enough to +receive the plug with which the Osmia will close up the lodging. There +is then nothing at her disposal except the cell proper, a spacious +apartment in which one of the Osmia's females will find ample +accommodation, for she is much smaller than the original occupant of the +chamber, no matter the sex; but there is not room for two cocoons at +a time, especially in view of the space taken up by the intervening +partition. Well, in those large, well-built chambers, formerly the homes +of Chalicodomae, the Osmia settles females and none but females. + +Let us now consider the long vestibule. Here, a partition is +constructed, encroaching slightly on the cell proper, and the residence +is divided into two unequal storeys, a large room below, housing a +female, and a narrow cabin above, containing a male. + +When the length of the vestibule permits, allowing for the space +required by the outer stopper, a third storey is built, smaller than the +second; and another male is lodged in this cramped corner. In this way +the old nest of the Mason-bee of the Pebbles is colonized, cell after +cell, by a single mother. + +The Osmia, as we see, is very frugal of the lodging that has fallen to +her share; she makes the best possible use of it, giving to the females +the spacious chambers of the Mason-bee and to the males the narrow +vestibules, subdivided into storeys when this is feasible. Economy of +space is the chief consideration, since her stay-at-home tastes do not +allow her to indulge in distant quests. She has to employ the site which +chance places at her disposal just as it is, now for a male and now for +a female. Here we see displayed, more clearly than ever, her power of +deciding the sex of the egg, in order to adapt it judiciously to the +conditions of the house-room available. + +I had offered at the same time to the Osmiae in my study some old +nests of the Mason-bee of the Shrubs, which are clay spheroids with +cylindrical cavities in them. These cavities are formed, as in the old +nests of the Mason-bee of the Pebbles, of the cell properly so-called +and of the exit-way which the perfect insect cut through the outer +coating at the time of its deliverance. Their diameter is about seven +millimetres (.273 inch.--Translator's Note.); their depth at the centre +of the heap is 23 millimetres (.897 inch.--Translator's Note.); and at +the edge averages 14 millimetres (.546 inch.--Translator's Note.) + +The deep central cells receive only the females of the Osmia; sometimes +even the two sexes together, with a partition in the middle, the female +occupying the lower and the male the upper storey. True, in such cases +economy of space is strained to the utmost, the apartments provided by +the Mason-bee of the Shrubs being very small as it is, despite their +entrance-halls. Lastly, the deeper cavities on the circumference are +allotted to females and the shallower to males. + +I will add that a single mother peoples each nest and also that she +proceeds from cell to cell without troubling to ascertain the depth. She +goes from the centre to the edges, from the edges to the centre, from a +deep cavity to a shallow cavity and vice versa, which she would not +do if the sexes were to follow upon each other in a settled order. For +greater certainty, I numbered the cells of one nest as each of them was +closed. On opening them later, I was able to see that the sexes were +not subjected to a chronological arrangement. Females were succeeded by +males and these by females without its being possible for me to make out +any regular sequence. Only--and this is the essential point--the deep +cavities were allotted to the females and the shallow ones to the males. + +We know that the Three-horned Osmia prefers to haunt the habitations of +the Bees who nidify in populous colonies, such as the Mason-bee of the +Sheds and the Hairy-footed Anthophora. Exercising the very greatest +care, I broke up some great lumps of earth removed from the banks +inhabited by the Anthophora and sent to me from Carpentras by my dear +friend and pupil M. Devillario. I examined them conscientiously in the +quiet of my study. I found the Osmia's cocoons arranged in short series, +in very irregular passages, the original work of which is due to the +Anthophora. Touched up afterwards, made larger or smaller, lengthened +or shortened, intersected with a network of crossings by the numerous +generations that had succeeded one another in the same city, they formed +an inextricable labyrinth. + +Sometimes these corridors did not communicate with any adjoining +apartment; sometimes they gave access to the spacious chamber of the +Anthophora, which could be recognized, in spite of its age, by its oval +shape and its coating of glazed stucco. In the latter case, the bottom +cell, which once constituted, by itself, the chamber of the Anthophora, +was always occupied by a female Osmia. Beyond it, in the narrow +corridor, a male was lodged, not seldom two, or even three. Of course, +clay partitions, the work of the Osmia, separated the different +inhabitants, each of whom had his own storey, his own closed cell. + +When the accommodation consisted of no more than a simple cylinder, +with no state-bedroom at the end of it--a bedroom always reserved for +a female--the contents varied with the diameter of the cylinder. The +series, of which the longest were series of four, included, with a +wider diameter, first one or two females, then one or two males. It also +happened, though rarely, that the series was reversed, that is to say, +it began with males and ended with females. Lastly, there were a good +many isolated cocoons, of one sex or the other. When the cocoon was +alone and occupied the Anthophora's cell, it invariably belonged to a +female. + +I have observed the same thing in the nests of the Mason-bee of the +Sheds, but not so easily. The series are shorter here, because the +Mason-bee does not bore galleries but builds cell upon cell. The work +of the whole swarm thus forms a stratum of cells that grows thicker from +year to year. The corridors occupied by the Osmia are the holes which +the Mason-bee dug in order to reach daylight from the deep layers. +In these short series, both sexes are usually present; and, if the +Mason-bee's chamber is at the end of the passage, it is inhabited by a +female Osmia. + +We come back to what the short tubes and the old nests of the Mason-bee +of the Pebbles have already taught us. The Osmia who, in tubes of +sufficient length, divides her whole laying into a continuous sequence +of females and a continuous sequence of males, now breaks it up into +short series in which both sexes are present. She adapts her sectional +layings to the exigencies of a chance lodging; she always places a +female in the sumptuous chamber which the Mason-bee or the Anthophora +occupied originally. + +Facts even more striking are supplied by the old nests of the Masked +Anthophora (A. personata, ILLIG.), old nests which I have seen utilized +by the Horned Osmia and the Three-horned Osmia at the same time. Less +frequently, the same nests serve for Latreille's Osmia. Let us first +describe the Masked Anthophora's nests. + +In a steep bank of sandy clay, we find a set of round, wide-open holes. +There are generally only a few of them, each about half an inch in +diameter. They are the entrance-doors leading to the Anthophora's abode, +doors always left open, even after the building is finished. Each of +them gives access to a short passage, sometimes straight, sometimes +winding, nearly horizontal, polished with minute care and varnished with +a sort of white glaze. It looks as if it had received a thin coat of +whitewash. On the inner surface of this passage, in the thickness of +the earthy bank, spacious oval niches have been excavated, communicating +with the corridor by means of a narrow bottle-neck, which is closed, +when the work is done, with a substantial mortar stopper. The Anthophora +polishes the outside of this stopper so well, smooths its surface so +perfectly, bringing it to the same level as that of the passage, is so +careful to give it the white tint of the rest of the wall that, when +the job is finished, it becomes absolutely impossible to distinguish the +entrance-door corresponding with each cell. + +The cell is an oval cavity dug in the earthy mass. The wall has the +same polish, the same chalky whiteness as the general passage. But the +Anthophora does not limit herself to digging oval niches: to make her +work more solid, she pours over the walls of the chamber a salivary +liquid which not only whitens and varnishes but also penetrates to a +depth of some millimetres into the sandy earth, which it turns into +a hard cement. A similar precaution is taken with the passage; and +therefore the whole is a solid piece of work capable of remaining in +excellent condition for years. + +Moreover, thanks to the wall hardened by the salivary fluid, the +structure can be removed from its matrix by chipping it carefully away. +We thus obtain, at least in fragments, a serpentine tube from which +hangs a single or double row of oval nodules that look like large grapes +drawn out lengthwise. Each of these nodules is a cell, the entrance to +which, carefully hidden, opens into the tube or passage. When she wishes +to leave her cell, in the spring, the Anthophora destroys the mortar +disk that closes the jar and thus reaches the general corridor, which +is quite open to the outer air. The abandoned nest provides a series of +pear-shaped cavities, of which the distended part is the old cell and +the contracted part the exit-neck, rid of its stopper. + +These pear-shaped hollows form splendid lodgings, impregnable +strongholds, in which the Osmiae find a safe and commodious retreat for +their families. The Horned Osmia and the Three-horned Osmia establish +themselves there at the same time. Although it is a little too large for +her, Latrielle's Osmia also appears very well satisfied with it. + +I have examined some forty of the superb cells utilized by each of the +first two. The great majority are divided into two storeys by means of +a transversal partition. The lower storey includes the larger portion +of the Anthophora's cell; the upper storey includes the rest of the +cell and a little of the bottle-neck that surmounts it. The two-roomed +dwelling is closed, in the passage, by a shapeless, bulky mass of dried +mud. What a clumsy artist the Osmia is, compared with the Anthophora! +Against the exquisite work of the Anthophora, partition and plug strike +a note as hideously incongruous as a lump of dirt on polished marble. + +The two apartments thus obtained are of a very unequal capacity, which +at once strikes the observer. I measured them with my five-millimetre +tube. On an average, the bottom one is represented by a column of sand +50 millimetres deep (1.95 inches.--Translator's Note.) and the top one +by a column of 15 millimetres (.585 inch.--Translator's Note.). The +holding-capacity of the one is therefore about three times as large as +that of the other. The cocoons enclosed present the same disparity. The +bottom one is big, the top one small. Lastly, the lower one belongs to a +female Osmia and the upper to a male Osmia. + +Occasionally the length of the bottle-neck allows of a fresh arrangement +and the cavity is divided into three storeys. The bottom one, which is +always the most spacious, contains a female; the two above, both smaller +than the first and one smaller than the other, contain males. + +Let us keep to the first case, which is always the most frequent. The +Osmia is in the presence of one of these pear-shaped hollows. It is a +find that must be employed to the best advantage: a prize of this sort +is rare and falls only to fortune's favourites. To lodge two females +in it at once is impossible; there is not sufficient room. To lodge two +males in it would be undue generosity to a sex that is entitled to but +the smallest consideration. Besides, the two sexes must be represented +in almost equal numbers. The Osmia decides upon one female, whose +portion shall be the better room, the lower one, which is larger, +better-protected and more nicely polished, and one male, whose portion +shall be the upper storey, a cramped attic, uneven and rugged in the +part which encroaches on the bottle-neck. This decision is proved by +numerous undeniable facts. Both Osmiae therefore can choose the sex +of the egg about to be laid, seeing that they are now breaking up the +laying into groups of two, a female and a male, as required by the +conditions of the lodging. + +I have only once found Latreille's Osmia established in the nest of the +Masked Anthophora. She had occupied but a small number of cells, because +the others were not free, being inhabited by the Anthophora. The cells +in question were divided into three storeys by partitions of green +mortar; the lower storey was occupied by a female, the two others by +males, with smaller cocoons. + +I came to an even more remarkable example. Two Anthidia of my district, +A. septemdentatum, LATR., and A. bellicosum, LEP., adopt as the home of +their offspring the empty shells of different snails: Helix aspersa, H. +algira, H. nemoralis, H. caespitum. The first-named, the Common Snail, +is the most often used, under the stone-heaps and in the crevices of old +walls. Both Anthidia colonize only the second whorl of the spiral. The +central part is too small and remains unoccupied. Even so with the front +whorl, the largest, which is left completely empty, so much so that, on +looking through the opening, it is impossible to tell whether the shell +does or does not contain the Bee's nest. We have to break this last +whorl if we would perceive the curious nest tucked away in the spiral. + +We then find first a transversal partition, formed of tiny bits of +gravel cemented by a putty made from resin, which is collected in fresh +drops from the oxycedrus and the Aleppo pine. Beyond this is a stout +barricade made up of rubbish of all kinds: bits of gravel, scraps of +earth, juniper-needles, the catkins of the conifers, small shells, +dried excretions of Snails. Next come a partition of pure resin, a large +cocoon in a roomy chamber, a second partition of pure resin and, lastly, +a smaller cocoon in a narrow chamber. The inequality of the two cells is +the necessary consequence of the shape of the shell, whose inner space +gains rapidly in width as the spiral gets nearer to the orifice. Thus, +by the mere general arrangement of the home and without any work on the +Bee's part beyond some slender partitions, a large room is marked out in +front and a much smaller room at the back. + +By a very remarkable exception, which I have mentioned casually +elsewhere, the males of the genus Anthidium are generally larger than +the females; and this is the case with the two species in particular +that divide the Snail's spiral with resin partitions. I collected some +dozens of nests of both species. In at least half the cases, the two +sexes were present together; the female, the smaller, occupied the front +cell and the male, the bigger, the back cell. Other cells, which were +smaller or too much obstructed at the back by the dried-up remains of +the Mollusc, contained only one cell, occupied at one time by a female +and at another by a male. A few, lastly, had both cells inhabited now by +two males and now by two females. The most frequent arrangement was the +simultaneous presence of both sexes, with the female in front and the +male behind. The Anthidia who make resin-dough and live in Snail-shells +can therefore alternate the sexes regularly to meet the exigencies of +the spiral dwelling-house. + +One more thing and I have done. My apparatus of reeds, fixed against the +walls of the garden, supplied me with a remarkable nest of the Horned +Osmia. The nest is established in a bit of reed 11 millimetres wide +inside. (.429 inch--Translator's Note.) It comprises thirteen cells and +occupies only half the cylinder, although the orifice is plugged with +the usual stopper. The laying therefore seems here to be complete. + +Well, this laying is arranged in a most singular fashion. There is +first, at a suitable distance from the bottom or the node of the reed, a +transversal partition, perpendicular to the axis of the tube. This marks +off a cell of unusual size, in which a female is lodged. After that, +in view of the excessive width of the tunnel, which is too great for +a series in single file, the Osmia appears to alter her mind. She +therefore builds a partition perpendicular to the transversal partition +which she has just constructed and thus divides the second storey into +two rooms, a larger room, in which she lodges a female, and a smaller, +in which she lodges a male. She next builds a second transversal +partition and a second longitudinal partition perpendicular to it. These +once more give two unequal chambers, stocked likewise, the large one +with a female, the smaller one with a male. + +From this third storey onwards, the Osmia abandons geometrical +accuracy; the architect seems to be a little out in her reckoning. The +transversal partitions become more and more slanting and the work +grows irregular, but always with a sprinkling of large chambers for the +females and small chambers for the males. Three females and two males +are housed in this way, the sexes alternating. + +By the time that the base of the eleventh cell is reached, the +transversal partition is once more almost perpendicular to the axis. +Here what happened at the bottom is repeated. There is no longitudinal +partition; and the spacious cell, covering the whole diameter of the +cylinder, receives a female. The edifice ends with two transversal +partitions and one longitudinal partition, which mark out, on the same +level, chambers twelve and thirteen, both of which contain males. + +There is nothing more curious than this mixing of the two sexes, when +we know with what precision the Osmia separates them in a linear series, +where the narrow width of the cylinder demands that the cells shall be +set singly, one above the other. Here, the Bee is making use of a tube +whose diameter is not suited to her work; she is constructing a complex +and difficult edifice, which perhaps would not possess the necessary +solidity if the ceilings were too broad. The Osmia therefore supports +these ceilings with longitudinal partitions; and the unequal chambers +resulting from the introduction of these partitions receive females at +one time and males at another, according to their capacity. + + + + +CHAPTER 5. PERMUTATIONS OF SEX. + +The sex of the egg is optional. The choice rests with the mother, who is +guided by considerations of space and, according to the accommodation +at her disposal, which is frequently fortuitous and incapable of +modification, places a female in this cell and a male in that, so that +both may have a dwelling of a size suited to their unequal development. +This is the unimpeachable evidence of the numerous and varied facts +which I have set forth. People unfamiliar with insect anatomy--the +public for whom I write--would probably give the following explanation +of this marvellous prerogative of the Bee: the mother has at her +disposal a certain number of eggs, some of which are irrevocably female +and the others irrevocably male: she is able to pick out of either group +the one which she wants at the actual moment; and her choice is decided +by the holding capacity of the cell that has to be stocked. Everything +would then be limited to a judicious selection from the heap of eggs. + +Should this idea occur to him, the reader must hasten to reject it. +Nothing could be more false, as the merest reference to anatomy will +show. The female reproductive apparatus of the Hymenoptera consists +generally of six ovarian tubes, something like glove-fingers, divided +into bunches of three and ending in a common canal, the oviduct, which +carries the eggs outside. Each of these glove-fingers is fairly wide +at the base, but tapers sharply towards the tip, which is closed. +It contains, arranged in a row, one after the other, like beads on a +string, a certain number of eggs, five or six for instance, of which the +lower ones are more or less developed, the middle ones half-way towards +maturity, and the upper ones very rudimentary. Every stage of evolution +is here represented, distributed regularly from bottom to top, from the +verge of maturity to the vague outlines of the embryo. The sheath clasps +its string of ovules so closely that any inversion of the order is +impossible. Besides, an inversion would result in a gross absurdity: the +replacing of a riper egg by another in an earlier stage of development. + +Therefore, in each ovarian tube, in each glove-finger, the emergence of +the eggs occurs according to the order governing their arrangement in +the common sheath; and any other sequence is absolutely impossible. +Moreover, at the nesting period, the six ovarian sheaths, one by one and +each in its turn, have at their base an egg which in a very short time +swells enormously. Some hours or even a day before the laying, that egg +by itself represents or even exceeds in bulk the whole of the ovigenous +apparatus. This is the egg which is on the point of being laid. It is +about to descend into the oviduct, in its proper order, at its proper +time; and the mother has no power to make another take its place. It is +this egg, necessarily this egg and no other, that will presently be laid +upon the provisions, whether these be a mess of honey or a live prey; it +alone is ripe, it alone is at the entrance to the oviduct; none of the +others, since they are farther back in the row and not at the right +stage of development, can be substituted at this crisis. Its birth is +inevitable. + +What will it yield, a male or a female? No lodging has been prepared, +no food collected for it; and yet both food and lodging have to be in +keeping with the sex that will proceed from it. And here is a much more +puzzling condition: the sex of that egg, whose advent is predestined, +has to correspond with the space which the mother happens to have found +for a cell. There is therefore no room for hesitation, strange though +the statement may appear: the egg, as it descends from its ovarian tube, +has no determined sex. It is perhaps during the few hours of its rapid +development at the base of its ovarian sheath, it is perhaps on its +passage through the oviduct that it receives, at the mother's pleasure, +the final impress that will produce, to match the cradle which it has to +fill, either a female or a male. + +Thereupon the following question presents itself. Let us admit that, +when the normal conditions remain, a laying would have yielded m females +and n males. Then, if my conclusions are correct, it must be in the +mother's power, when the conditions are different, to take from the m +group and increase the n group to the same extent; it must be possible +for her laying to be represented as m-1, m-2, m-3, etc. females and by +n+1, n+2, n+3, etc. males, the sum of m+n remaining constant, but one of +the sexes being partly permuted into the other. The ultimate conclusion +even cannot be disregarded: we must admit a set of eggs represented +by m-m, or zero, females and of n+m males, one of the sexes being +completely replaced by the other. Conversely, it must be possible for +the feminine series to be augmented from the masculine series to the +extent of absorbing it entirely. It was to solve this question and some +others connected with it that I undertook, for the second time, to rear +the Three-horned Osmia in my study. + +The problem on this occasion is a more delicate one; but I am +also better-equipped. My apparatus consists of two small, closed +packing-cases, with the front side of each pierced with forty holes, +in which I can insert my glass tubes and keep them in a horizontal +position. I thus obtain for the Bees the darkness and mystery which suit +their work and for myself the power of withdrawing from my hive, at any +time, any tube that I wish, with the Osmia inside, so as to carry it +to the light and follow, if need be with the aid of the lens, the +operations of the busy worker. My investigations, however frequent and +minute, in no way hinder the peaceable Bee, who remains absorbed in her +maternal duties. + +I mark a plentiful number of my guests with a variety of dots on the +thorax, which enables me to follow any one Osmia from the beginning +to the end of her laying. The tubes and their respective holes are +numbered; a list, always lying open on my desk, enables me to note from +day to day, sometimes from hour to hour, what happens in each tube and +particularly the actions of the Osmiae whose backs bear distinguishing +marks. As soon as one tube is filled, I replace it by another. Moreover, +I have scattered in front of either hive a few handfuls of empty +Snail-shells, specially chosen for the object which I have in view. +Reasons which I will explain later led me to prefer the shells of Helix +caespitum. Each of the shells, as and when stocked, received the date +of the laying and the alphabetical sign corresponding with the Osmia to +whom it belonged. In this way, I spent five or six weeks in continual +observation. To succeed in an enquiry, the first and foremost condition +is patience. This condition I fulfilled; and it was rewarded with the +success which I was justified in expecting. + +The tubes employed are of two kinds. The first, which are cylindrical +and of the same width throughout, will be of use for confirming the +facts observed in the first year of my experiments in indoor rearing. +The others, the majority, consist of two cylinders which are of very +different diameters, set end to end. The front cylinder, the one which +projects a little way outside the hive and forms the entrance-hole, +varies in width between 8 and 12 millimetres. (Between.312 to .468 +inch.--Translator's Note.) The second, the back one, contained +entirely within my packing-case, is closed at its far end and is 5 to 6 +millimetres (.195 to.234 inch.--Translator's Note.) in diameter. Each of +the two parts of the double-galleried tunnel, one narrow and one wide, +measures at most a decimetre (3.9 inches.--Translator's Note.) in +length. I thought it advisable to have these short tubes, as the Osmia +is thus compelled to select different lodgings, each of them being +insufficient in itself to accommodate the total laying. In this way I +shall obtain a greater variety in the distribution of the sexes. Lastly, +at the mouth of each tube, which projects slightly outside the case, +there is a little paper tongue, forming a sort of perch on which the +Osmia alights on her arrival and giving easy access to the house. With +these facilities, the swarm colonized fifty-two double-galleried tubes, +thirty-seven cylindrical tubes, seventy-eight Snail-shells and a few old +nests of the Mason-bee of the Shrubs. From this rich mine of material I +will take what I want to prove my case. + +Every series, even when incomplete, begins with females and ends with +males. To this rule I have not yet found an exception, at least in +galleries of normal diameter. In each new abode, the mother busies +herself first of all with the more important sex. Bearing this point +in mind, would it be possible for me, by manoeuvring, to obtain an +inversion of this order and make the laying begin with males? I +think so, from the results already ascertained and the irresistible +conclusions to be drawn from them. The double-galleried tubes are +installed in order to put my conjectures to the proof. + +The back gallery, 5 or 6 millimetres (.195 to.234 inch.--Translator's +Note.) wide, is too narrow to serve as a lodging for normally developed +females. If, therefore, the Osmia, who is very economical of her space, +wishes to occupy them, she will be obliged to establish males there. +And her laying must necessarily begin here, because this corner is +the rear-most part of the tube. The foremost gallery is wide, with an +entrance-door on the front of the hive. Here, finding the conditions to +which she is accustomed, the mother will go on with her laying in the +order which she prefers. + +Let us now see what has happened. Of the fifty-two double galleried +tubes, about a third did not have their narrow passage colonized. The +Osmia closed its aperture communicating with the large passage; and the +latter alone received the eggs. This waste of space was inevitable. +The female Osmiae, though nearly always larger than the males, present +marked differences among one another: some are bigger, some are smaller. +I had to adjust the width of the narrow galleries to Bees of average +dimensions. It may happen therefore that a gallery is too small to admit +the large-sized mothers to whom chance allots it. When the Osmia is +unable to enter the tube, obviously she will not colonize it. She then +closes the entrance to this space which she cannot use and does her +laying beyond it, in the wide tube. Had I tried to avoid these useless +apparatus by choosing tubes of larger calibre, I should have encountered +another drawback: the medium-sized mothers, finding themselves almost +comfortable, would have decided to lodge females there. I had to be +prepared for it: as each mother selected her house at will and as I was +unable to interfere in her choice, a narrow tube would be colonized or +not, according as the Osmia who owned it was or was not able to make her +way inside. + +There remain some forty pairs of tubes with both galleries colonized. In +these there are two things to take into consideration. The narrow +rear tubes of 5 or 5 1/2 millimetres (.195 to.214 inch.--Translator's +Note.)--and these are the most numerous--contain males and males only, +but in short series, between one and five. The mother is here so much +hampered in her work that they are rarely occupied from end to end; the +Osmia seems in a hurry to leave them and to go and colonize the front +tube, whose ample space will leave her the liberty of movement necessary +for her operations. The other rear tubes, the minority, whose diameter +is about 6 millimetres (.234 inch.--Translator's Note.), contain +sometimes only females and sometimes females at the back and males +towards the opening. One can see that a tube a trifle wider and a mother +slightly smaller would account for this difference in the results. +Nevertheless, as the necessary space for a female is barely provided +in this case, we see that the mother avoids as far as she can a two-sex +arrangement beginning with males and that she adopts it only in the +last extremity. Finally, whatever the contents of the small tube may +be, those of the large one, following upon it, never vary and consist of +females at the back and males in front. + +Though incomplete, because of circumstances very difficult to control, +the result of the experiment is none the less very striking. Twenty-five +apparatus contain only males in their narrow gallery, in numbers varying +from a minimum of one to a maximum of five. After these comes the colony +of the large gallery, beginning with females and ending with males. And +the layings in these apparatus do not always belong to late summer or +even to the intermediate period: a few small tubes contain the earliest +eggs of the Osmiae. A couple of Osmiae, more forward than the others, +set to work on the 23rd of April. Both of them started their laying by +placing males in the narrow tubes. The meagre supply of provisions was +enough in itself to show the sex, which proved later to be in accordance +with my anticipations. We see then that, by my artifices, the whole +swarm starts with the converse of the normal order. This inversion is +continued, at no matter what period, from the beginning to the end of +the operations. The series which, according to rule, would begin with +females now begins with males. Once the larger gallery is reached, the +laying is pursued in the usual order. + +We have advanced one step and that no small one: we have seen that +the Osmia, when circumstances require it, is capable of reversing the +sequence of the sexes. Would it be possible, provided that the tube were +long enough, to obtain a complete inversion, in which the entire series +of the males should occupy the narrow gallery at the back and the entire +series of the females the roomy gallery in front? I think not; and I +will tell you why. + +Long and narrow cylinders are by no means to the Osmia's taste, not +because of their narrowness but because of their length. Remember that +for each load of honey brought the worker is obliged to move backwards +twice. She enters, head first, to begin by disgorging the honey-syrup +from her crop. Unable to turn in a passage which she blocks entirely, +she goes out backwards, crawling rather than walking, a laborious +performance on the polished surface of the glass and a performance +which, with any other surface, would still be very awkward, as the wings +are bound to rub against the wall with their free end and are liable to +get rumpled or bent. She goes out backwards, reaches the outside, turns +round and goes in again, but this time the opposite way, so as to brush +off the load of pollen from her abdomen on to the heap. If the gallery +is at all long, this crawling backwards becomes troublesome after a +time; and the Osmia soon abandons a passage that is too small to allow +of free movement. I have said that the narrow tubes of my apparatus +are, for the most part, only very incompletely colonized. The Bee, after +lodging a small number of males in them, hastens to leave them. In the +wide front gallery, she can stay where she is and still be able to turn +round easily for her different manipulations; she will avoid those two +long journeys backwards, which are so exhausting and so bad for her +wings. + +Another reason no doubt prompts her not to make too great a use of the +narrow passage, in which she would establish males, followed by females +in the part where the gallery widens. The males have to leave their +cells a couple of weeks or more before the females. If they occupy the +back of the house, they will die prisoners or else they will overturn +everything on their way out. This risk is avoided by the order which the +Osmia adopts. + +In my tubes with their unusual arrangement, the mother might well find +the dilemma perplexing: there is the narrowness of the space at her +disposal and there is the emergence later on. In the narrow tubes, the +width is insufficient for the females; on the other hand, if she lodges +males there, they are liable to perish, since they will be prevented +from issuing at the proper moment. This would perhaps explain the +mother's hesitation and her obstinacy in settling females in some of my +apparatus which looked as if they could suit none but males. + +A suspicion occurs to me, a suspicion aroused by my attentive +examination of the narrow tubes. All, whatever the number of their +inmates, are carefully plugged at the opening, just as separate tubes +would be. It might therefore be the case that the narrow gallery at the +back was looked upon by the Osmia not as the prolongation of the large +front gallery, but as an independent tube. The facility with which +the worker turns as soon as she reaches the wide tube, her liberty of +action, which is now as great as in a doorway communicating with the +outer air, might well be misleading and cause the Osmia to treat the +narrow passage at the back as though the wide passage in front did not +exist. This would account for the placing of the female in the large +tube above the males in the small tube, an arrangement contrary to her +custom. + +I will not undertake to decide whether the mother really appreciates the +danger of my snares, or whether she makes a mistake in considering +only the space at her disposal and beginning with males. At any rate, +I perceive in her a tendency to deviate as little as possible from the +order which safeguards the emergence of the two sexes. This tendency is +demonstrated by her repugnance to colonizing my narrow tubes with long +series of males. However, so far as we are concerned, it does not matter +much what passes at such times in the Osmia's little brain. Enough for +us to know that she dislikes narrow and long tubes, not because they are +narrow, but because they are at the same time long. + +And, in fact, she does very well with a short tube of the same diameter. +Such are the cells in the old nests of the Mason-bee of the Shrubs +and the empty shells of the Garden Snail. With the short tube, the two +disadvantages of the long tube are avoided. She has very little of that +crawling backwards to do when she has a Snail-shell for the home of +her eggs and scarcely any when the home is the cell of the Mason-bee. +Moreover, as the stack of cocoons numbers two or three at most, the +deliverance will be exempt from the difficulties attached to a long +series. To persuade the Osmia to nidify in a single tube long enough to +receive the whole of her laying and at the same time narrow enough +to leave her only just the possibility of admittance appears to me +a project without the slightest chance of success: the Bee would +stubbornly refuse such a dwelling or would content herself with +entrusting only a very small portion of her eggs to it. On the other +hand, with narrow but short cavities, success, without being easy, +seems to me at least quite possible. Guided by these considerations, +I embarked upon the most arduous part of my problem: to obtain the +complete or almost complete permutation of one sex with the other; +to produce a laying consisting only of males by offering the mother a +series of lodgings suited only to males. + +Let us in the first place consult the old nests of the Mason-bee of the +Shrubs. I have said that these mortar spheroids, pierced all over +with little cylindrical cavities, are adopted pretty eagerly by the +Three-horned Osmia, who colonizes them before my eyes with females in +the deep cells and males in the shallow cells. That is how things go +when the old nest remains in its natural state. With a grater, however, +I scrape the outside of another nest so as to reduce the depth of +the cavities to some ten millimetres. (About two-fifths of an +inch.--Translator's Note.) This leaves in each cell just room for one +cocoon, surmounted by the closing stopper. Of the fourteen cavities in +the nests, I leave two intact, measuring fifteen millimetres in depth. +(.585 inch.--Translator's Note.) Nothing could be more striking than the +result of this experiment, made in the first year of my home rearing. +The twelve cavities whose depth had been reduced all received males; the +two cavities left untouched received females. + +A year passes and I repeat the experiment with a nest of fifteen cells; +but this time all the cells are reduced to the minimum depth with the +grater. Well, the fifteen cells, from first to last, are occupied by +males. It must be quite understood that, in each case, all the offspring +belonged to one mother, marked with her distinguishing spot and kept +in sight as long as her laying lasted. He would indeed be difficult to +please who refused to bow before the results of these two experiments. +If, however, he is not yet convinced, here is something to remove his +last doubts. + +The Three-horned Osmia often settles her family in old shells, +especially those of the Common Snail (Helix aspersa), who is so common +under the stone-heaps and in the crevices of the little unmortared walls +that support our terraces. In this species, the spiral is wide open, so +that the Osmia, penetrating as far down as the helical passage permits, +finds, immediately above the point which is too narrow to pass, the +space necessary for the cell of a female. This cell is succeeded by +others, wider still, always for females, arranged in a line in the same +way as in a straight tube. In the last whorl of the spiral, the diameter +would be too great for a single row. Then longitudinal partitions are +added to the transverse partitions, the whole resulting in cells of +unequal dimensions in which males predominate, mixed with a few females +in the lower storeys. The sequence of the sexes is therefore what it +would be in a straight tube and especially in a tube with a wide bore, +where the partitioning is complicated by subdivisions on the same level. +A single Snail-shell contains room for six or eight cells. A large, +rough earthen stopper finishes the nest at the entrance to the shell. + +As a dwelling of this sort could show us nothing new, I chose for my +swarm the Garden Snail (Helix caespitum), whose shell, shaped like a +small, swollen Ammonite, widens by slow degrees, the diameter of the +usable portion, right up to the mouth, being hardly greater than that +required by a male Osmia-cocoon. Moreover, the widest part, in which +a female might find room, has to receive a thick stopping-plug, below +which there will often be a free space. Under all these conditions, the +house will hardly suit any but males arranged one after the other. + +The collection of shells placed at the foot of each hive includes +specimens of different sizes. The smallest are 18 millimetres (.7 +inch.--Translator's Note.) in diameter and the largest 24 millimetres +(.936 inch.--Translator's Note.) There is room for two cocoons, or three +at most, according to their dimensions. + +Now these shells were used by my visitors without any hesitation, +perhaps even with more eagerness than the glass tubes, whose slippery +sides might easily be a little annoying to the Bee. Some of them were +occupied on the first few days of the laying; and the Osmia who +had started with a home of this sort would pass next to a second +Snail-shell, in the immediate neighbourhood of the first, to a third, a +fourth and others still, always close to one another, until her ovaries +were emptied. The whole family of one mother would thus be lodged in +Snail-shells which were duly marked with the date of the laying and a +description of the worker. The faithful adherents of the Snail-shell +were in the minority. The greater number left the tubes to come to +the shells and then went back from the shells to the tubes. All, after +filling the spiral staircase with two or three cells, closed the house +with a thick earthen stopper on a level with the opening. It was a long +and troublesome task, in which the Osmia displayed all her patience as +a mother and all her talents as a plasterer. There were even some who, +scrupulous to excess, carefully cemented the umbilicus, a hole which +seemed to inspire them with distrust as being able to give access to the +interior of the dwelling. It was a dangerous-looking cavity, which for +the greater safety of the family it was prudent to block up. + +When the pupae are sufficiently matured, I proceed to examine +these elegant abodes. The contents fill me with joy: they fulfil my +anticipations to the letter. The great, the very great majority of the +cocoons turn out to be males; here and there, in the bigger cells, a +few rare females appear. The smallness of the space has almost done away +with the sixty-eight Snail-shells colonized. But, of this total number, +I must use only those series which received an entire laying and +were occupied by the same Osmia from the beginning to the end of +the egg-season. Here are a few examples, taken from among the most +conclusive. + +From the 6th of May, when she started operations, to the 25th of +May, the date at which her laying ceased, the Osmia occupied seven +Snail-shells in succession. Her family consists of fourteen cocoons, +a number very near the average; and, of these fourteen cocoons, twelve +belong to males and only two to females. These occupy the seventh and +thirteenth places in chronological order. + +Another, between the 9th and 27th of May, stocked six Snail-shells with +a family of thirteen, including ten males and three females. The places +occupied by the latter in the series were numbers 3, 4 and 5. + +A third, between the 2nd and 29th of May, colonized eleven Snail-shells, +a prodigious task. This industrious one was also exceedingly prolific. +She supplied me with a family of twenty-six, the largest which I have +ever obtained from one Osmia. Well, this abnormal progeny consisted of +twenty-five males and one female, one alone, occupying place 17. + +There is no need to go on, after this magnificent example, especially as +the other series would all, without exception, give us the same result. +Two facts are immediately obvious. The Osmia is able to reverse the +order of her laying and to start with a more or less long series of +males before producing any females. In the first case, the first female +appears as number 7; in the third, as number 17. There is something +better still; and this is the proposition which I was particularly +anxious to prove: the female sex can be permuted with the male sex and +can be permuted to the point of disappearing altogether. We see this +especially in the third case, where the presence of a solitary female +in a family of twenty-six is due to the somewhat larger diameter of the +corresponding Snail-shell and also, no doubt, to some mistake on the +mother's part, for the female cocoon, in a series of two, occupies the +upper storey, the one next to the orifice, an arrangement which the +Osmia appears to me to dislike. + +This result throws so much light on one of the darkest corners of +biology that I must attempt to corroborate it by means of even more +conclusive experiments. I propose next year to give the Osmiae nothing +but Snail-shells for a lodging, picked out one by one, and rigorously +to deprive the swarm of any other retreat in which the laying could be +effected. Under these conditions, I ought to obtain nothing but males, +or nearly, for the whole swarm. + +There would still remain the inverse permutation: to obtain only females +and no males, or very few. The first permutation makes the second seem +very probable, although I cannot as yet conceive a means of realizing +it. The only condition which I can regulate is the dimensions of the +home. When the rooms are small, the males abound and the females tend to +disappear. With generous quarters, the converse would not take place. I +should obtain females and afterwards an equal number of males, confined +in small cells which, in case of need, would be bounded by numerous +partitions. The factor of space does not enter into the question here. +What artifice can we then employ to provoke this second permutation? So +far, I can think of nothing that is worth attempting. + +It is time to conclude. Leading a retired life, in the solitude of +a village, having quite enough to do with patiently and obscurely +ploughing my humble furrow, I know little about modern scientific views. +In my young days I had a passionate longing for books and found it +difficult to procure them; to-day, when I could almost have them if I +wanted, I am ceasing to wish for them. It is what usually happens as +life goes on. I do not therefore know what may have been done in the +direction whither this study of the sexes has led us. If I am stating +propositions that are really new or at least more comprehensive than the +propositions already known, my words will perhaps sound heretical. No +matter: as a simple translator of facts, I do not hesitate to make my +statement, being fully persuaded that time will turn my heresy into +orthodoxy. I will therefore recapitulate my conclusions. + +Bees lay their eggs in series of first females and then males, when +the two sexes are of different sizes and demand an unequal quantity of +nourishment. When the two sexes are alike in size, the same sequence may +occur, but less regularly. + +This dual arrangement disappears when the place chosen for the nest +is not large enough to contain the entire laying. We then see broken +layings, beginning with females and ending with males. + +The egg, as it issues from the ovary, has not yet a fixed sex. The final +impress that produces the sex is given at the moment of laying or a +little before. + +So as to be able to give each larva the amount of space and food that +suits it according as it is male or female, the mother can choose the +sex of the egg which she is about to lay. To meet the conditions of the +building, which is often the work of another or else a natural retreat +that admits of little or no alteration, she lays either a male egg or +a female egg as she pleases. The distribution of the sexes depends upon +herself. Should circumstances require it, the order of the laying can +be reversed and begin with males; lastly, the entire laying can contain +only one sex. + +The same privilege is possessed by the predatory Hymenoptera, the Wasps, +at least by those in whom the two sexes are of a different size and +consequently require an amount of nourishment that is larger in the one +case than in the other. The mother must know the sex of the egg which +she is going to lay; she must be able to choose the sex of that egg so +that each larva may obtain its proper portion of food. + +Generally speaking, when the sexes are of different sizes, every insect +that collects food and prepares or selects a dwelling for its offspring +must be able to choose the sex of the egg in order to satisfy without +mistake the conditions imposed upon it. + +The question remains how this optional assessment of the sexes is +effected. I know absolutely nothing about it. If I should ever learn +anything about this delicate point, I shall owe it to some happy chance +for which I must wait, or rather watch, patiently. Towards the end of my +investigations, I heard of a German theory which relates to the Hive-bee +and comes from Dzierzon, the apiarist. (Johann Dzierzon, author of +"Theorie und Praxis des neuen Bienenfreundes."--Translator's Note.) If I +understand it aright, according to the very incomplete documents which I +have before me, the egg, as it issues from the ovary, is said already to +possess a sex, which is always the same; it is originally male; and it +becomes female by fertilization. The males are supposed to proceed from +non-fertilized eggs, the females from fertilized eggs. The Queen-bee +would thus lay female eggs or male eggs according as she fertilized them +or not while they were passing into her oviduct. + +Coming from Germany, this theory cannot but inspire me with profound +distrust. As it has been given acceptance, with rash precipitancy, in +standard works, I will overcome my reluctance to devoting my attention +to Teutonic ideas and will submit it not to the test of argument, which +can always be met by an opposite argument, but to the unanswerable test +of facts. + +For this optional fertilization, determining the sex, the mother's +organism requires a seminal reservoir which distils its drop of sperm +upon the egg contained in the oviduct and thus gives it a feminine +character, or else leaves it its original character, the male character, +by refusing it that baptism. This reservoir exists in the Hive-bee. +Do we find a similar organ in the other Hymenoptera, whether +honey-gatherers or hunters? The anatomical treatises are either silent +on this point or, without further enquiry, apply to the order as a whole +the data provided by the Hive-bee, however much she differs from the +mass of Hymenoptera owing to her social habits, her sterile workers and +especially her tremendous fertility, extending over so long a period. + +I at first doubted the universal presence of this spermatic receptacle, +having failed to find it under my scalpel in my former investigations +into the anatomy of the Sphex-wasps and some other game-hunters. But +this organ is so delicate and so small that it very easily escapes the +eye, especially when our attention is not specially directed in search +of it; and, even when we are looking for it and it only, we do not +always succeed in discovering it. We have to find a globule attaining +in many cases hardly as much as a millimetre (About one-fiftieth of an +inch.--Translator's Note.) in diameter, a globule headed amidst a tangle +of air-ducts and fatty patches, of which it shares the colour, a dull +white. Then again, the merest slip of the forceps is enough to destroy +it. My first investigations, therefore, which concerned the reproductive +apparatus as a whole, might very well have allowed it to pass +unperceived. + +In order to know the rights of the matter once and for all, as the +anatomical treatises taught me nothing, I once more fixed my microscope +on its stand and rearranged my old dissecting-tank, an ordinary tumbler +with a cork disk covered with black satin. This time, not without a +certain strain on my eyes, which are already growing tired, I succeeded +in finding the said organ in the Bembex-wasps, the Halicti (Cf. +Chapters 12 to 14 of the present volume.--Translator's Note.), the +Carpenter-bees, the Bumble-bees, the Andrenae (A species of Burrowing +Bees.--Translator's Note.) and the Megachiles. (Or Leaf-cutting Bees. +Cf. Chapter 8 of the present volume.--Translator's Note.) I failed in +the case of the Osmiae, the Chalicodomae and the Anthophorae. Is the +organ really absent? Or was there want of skill on my part? I +lean towards want of skill and admit that all the game-hunting and +honey-gathering Hymenoptera possess a seminal receptacle, which can be +recognized by its contents, a quantity of spiral spermatozoids whirling +and twisting on the slide of the microscope. + +This organ once accepted, the German theory becomes applicable to all +the Bees and all the Wasps. When copulating, the female receives the +seminal fluid and holds it stored in her receptacle. From that moment, +the two procreating elements are present in the mother at one and the +same time: the female element, the ovule; and the male element, the +spermatozoid. At the egg-layer's will, the receptacle bestows a tiny +drop of its contents upon the matured ovule, when it reaches +the oviduct, and you have a female egg; or else it withholds its +spermatozoids and you have an egg that remains male, as it was at first. +I readily admit it: the theory is very simple, lucid and seductive. But +is it correct? That is another question. + +One might begin by reproaching it with making a singular exception to +one of the most general rules. Which of us, casting his eyes over the +whole zoological progression, would dare to assert that the egg is +originally male and that it becomes female by fertilization? Do not the +two sexes both call for the assistance of the fertilizing element? If +there be one undoubted truth, it is certainly that. We are, it is true, +told very curious things about the Hive-bee. I will not discuss them: +this Bee stands too far outside the ordinary limits; and then the facts +asserted are far from being accepted by everybody. But the non-social +Bees and the predatory insects have nothing special about their laying. +Then why should they escape the common rule, which requires that every +living creature, male as well as female, should come from a fertilized +ovule? In its most solemn act, that of procreation, life is one and +uniform; what it does here it does there and there and everywhere. What! +The sporule of a scrap of moss requires an antherozoid before it is +fit to germinate; and the ovule of a Scolia, that proud huntress, can +dispense with the equivalent in order to hatch and produce a male? These +new-fangled theories seem to me to have very little value. + +One might also bring forward the case of the Three-pronged Osmia, who +distributes the two sexes without any order in the hollow of her reed. +What singular whim is the mother obeying when, without decisive motive, +she opens her seminal phial at haphazard to anoint a female egg, or +else keeps it closed, also at haphazard, to allow a male egg to pass +unfertilized? I could imagine impregnation being given or withheld +for periods of some duration; but I cannot understand impregnation and +non-impregnation following upon each other anyhow, in any sort of order, +or rather with no order it all. The mother has just fertilized an egg. +Why should she refuse to fertilize the next, when neither the provisions +nor the lodgings differ in the smallest respect from the previous +provisions and lodgings? These capricious alternations, so unreasonable +and so exceedingly erratic, are scarcely appropriate to an act of such +importance. + +But I promised not to argue and I find myself arguing. My reasoning is +too fine for dull wits. I will pass on and come to the brutal fact, the +real sledge-hammer blow. + +Towards the end of the Bee's operations, in the first week of June, the +last acts of the Three-horned Osmia become so exceptionally interesting +that I made her the object of redoubled observation. The swarm at this +time is greatly reduced in numbers. I have still some thirty laggards, +who continue very busy, though their work is in vain. I see some very +conscientiously stopping up the entrance to a tube or a Snail-shell in +which they have laid nothing at all. Others are closing the home after +only building a few partitions, or even mere attempts at partitions. +Some are placing at the back of a new gallery a pinch of pollen which +will benefit nobody and then shutting up the house with an earthen +stopper as thick, as carefully made as though the safety of a family +depended on it. Born a worker, the Osmia must die working. When her +ovaries are exhausted, she spends the remainder of her strength on +useless works: partitions, plugs, pollen-heaps, all destined to be left +unemployed. The little animal machine cannot bring itself to be inactive +even when there is nothing more to be done. It goes on working so that +its last vibrations of energy may be used up in fruitless labour. I +commend these aberrations to the staunch supporters of reasoning-powers +in the animal. + +Before coming to these useless tasks, my laggards have laid their last +eggs, of which I know the exact cells, the exact dates. These eggs, as +far as the microscopes can tell, differ in no respect from the others, +the older ones. They have the same dimensions, the same shape, the same +glossiness, the same look of freshness. Nor are their provisions in +any way peculiar, being very well suited to the males, who conclude the +laying. And yet these last eggs do not hatch: they wrinkle, fade and +wither on the pile of food. In one case, I count three or four sterile +eggs among the last lot laid; in another, I find two or only one. +Elsewhere in the swarm, fertile eggs have been laid right up to the end. + +Those sterile eggs, stricken with death at the moment of their birth, +are too numerous to be ignored. Why do they not hatch like the other +eggs, which outwardly they resemble in every respect? They have received +the same attention from the mother and the same portion of food. The +searching microscope shows me nothing in them to explain the fatal +ending. + +To the unprejudiced mind, the answer is obvious. Those eggs do not hatch +because they have not been fertilized. Any animal or vegetable egg that +had not received the life-giving impregnation would perish in the same +way. No other answer is possible. It is no use talking of the distant +period of the laying: eggs of the same period laid by other mothers, +eggs of the same date and likewise the final ones of a laying, are +perfectly fertile. Once more, they do not hatch because they were not +fertilized. + +And why were they not fertilized? Because the seminal receptacle, so +tiny, so difficult to see that it sometimes escaped me despite all +my scrutiny, had exhausted its contents. The mothers in whom this +receptacle retained a remnant of sperm to the end had their last eggs as +fertile as the first; the others, whose seminal reservoir was exhausted +too soon, had their last-born stricken with death. All this seems to me +as clear as daylight. + +If the unfertilized eggs perish without hatching, those which hatch and +produce males are therefore fertilized; and the German theory falls to +the ground. + +Then what explanation shall I give of the wonderful facts which I have +set forth? Why, none, absolutely none. I do not explain facts, I relate +them. Growing daily more sceptical of the interpretations suggested to +me and more hesitating as to those which I may have to suggest myself, +the more I observe and experiment, the more clearly I see rising out of +the black mists of possibility an enormous note of interrogation. + +Dear insects, my study of you has sustained me and continues to sustain +me in my heaviest trials. I must take leave of you for to-day. The ranks +are thinning around me and the long hopes have fled. Shall I be able to +speak to you again? (This is the closing paragraph of Volume 3 of the +"Souvenirs entomologiques," of which the author has lived to publish +seven more volumes, containing over 2,500 pages and nearly 850,000 +words.--Translator's Note.) + + + + +CHAPTER 6. INSTINCT AND DISCERNMENT. + +The Pelopaeus (A Mason-wasp forming the subject of essays which have not +yet been published in English.--Translator's Note.) gives us a very poor +idea of her intellect when she plasters up the spot in the wall where +the nest which I have removed used to stand, when she persists in +cramming her cell with Spiders for the benefit of an egg no longer there +and when she dutifully closes a cell which my forceps has left +empty, extracting alike germ and provisions. The Mason-bees (Cf. "The +Mason-bees": chapter 7.--Translator's Note.), the caterpillar of the +Great Peacock Moth (Cf. "Social Life in the Insect World" by J.H. Fabre, +translated by Bernard Miall: chapter 14.--Translator's Note.) and +many others, when subjected to similar tests, are guilty of the same +illogical behaviour: they continue, in the normal order, their series +of industrious actions, though an accident has now rendered them all +useless. Just like millstones unable to cease revolving though there be +no corn left to grind, let them once be given the compelling power and +they will continue to perform their task despite its futility. Are they +then machines? Far be it from me to think anything so foolish. + +It is impossible to make definite progress on the shifting sands +of contradictory facts: each step in our interpretation may find us +embogged. And yet these facts speak so loudly that I do not hesitate +to translate their evidence as I understand it. In insect mentality, we +have to distinguish two very different domains. One of these is INSTINCT +properly so called, the unconscious impulse that presides over the +most wonderful part of what the creature achieves. Where experience and +imitation are of absolutely no avail, instinct lays down its inflexible +law. It is instinct and instinct alone that makes the mother build for a +family which she will never see; that counsels the storing of +provisions for the unknown offspring; that directs the sting towards the +nerve-centres of the prey and skilfully paralyses it, so that the game +may keep good; that instigates, in fine, a host of actions wherein +shrewd reason and consummate science would have their part, were the +creature acting through discernment. + +This faculty is perfect of its kind from the outset, otherwise the +insect would have no posterity. Time adds nothing to it and takes +nothing from it. Such as it was for a definite species, such it is +to-day and such it will remain, perhaps the most settled zoological +characteristic of them all. It is not free nor conscious in its +practice, any more than is the faculty of the stomach for digestion +or that of the heart for pulsation. The phases of its operations are +predetermined, necessarily entailed one by another; they suggest a +system of clock-work wherein one wheel set in motion brings about the +movement of the next. This is the mechanical side of the insect, +the fatum, the only thing which is able to explain the monstrous +illogicality of a Pelopaeus when misled by my artifices. Is the Lamb +when it first grips the teat a free and conscious agent, capable of +improvement in its difficult art of taking nourishment? The insect is no +more capable of improvement in its art, more difficult still, of giving +nourishment. + +But, with its hide-bound science ignorant of itself, pure insect, if it +stood alone, would leave the insect unarmed in the perpetual conflict +of circumstances. No two moments in time are identical; though the +background remain the same, the details change; the unexpected rises on +every side. In this bewildering confusion, a guide is needed to seek, +accept, refuse and select; to show preference for this and indifference +to that; to turn to account, in short, anything useful that occasion may +offer. This guide the insect undoubtedly possesses, to a very manifest +degree. It is the second province of its mentality. Here it is conscious +and capable of improvement by experience. I dare not speak of this +rudimentary faculty as intelligence, which is too exalted a title: I +will call it DISCERNMENT. The insect, in exercising its highest gifts, +discerns, differentiates between one thing and another, within the +sphere of its business, of course; and that is about all. + +As long as we confound acts of pure instinct and acts of discernment +under the same head, we shall fall back into those endless discussions +which embitter controversy without bringing us one step nearer to the +solution of the problem. Is the insect conscious of what it does? Yes +and no. No, if its action is in the province of instinct; yes, if the +action is in that of discernment. Are the habits of an insect capable of +modification? No, decidedly not, if the habit in question belongs to the +province of instinct; yes, if it belongs to that of discernment. Let us +state this fundamental distinction more precisely by the aid of a few +examples. + +The Pelopaeus builds her cells with earth already softened, with mud. +Here we have instinct, the unalterable characteristic of the worker. +She has always built in this way and always will. The passing ages will +never teach her, neither the struggle for life nor the law of selection +will ever induce her to imitate the Mason-bee and collect dry dust +for her mortar. This mud nest needs a shelter against the rain. The +hiding-place under a stone suffices at first. But should she find +something better, the potter takes possession of that something better +and instals herself in the home of man. (The Pelopaeus builds in the +fire-places of houses.--Translator's Note.) There we have discernment, +the source of some sort of capacity for improvement. + +The Pelopaeus supplies her larvae with provisions in the form of +Spiders. There you have instinct. The climate, the longitude or +latitude, the changing seasons, the abundance or scarcity of game +introduce no modification into this diet, though the larva shows itself +satisfied with other fare provided by myself. Its forebears were brought +up on Spiders; their descendants consumed similar food; and their +posterity again will know no other. Not a single circumstance, however +favourable, will ever persuade the Pelopaeus that young Crickets, for +instance, are as good as Spiders and that her family would accept them +gladly. Instinct binds her down to the national diet. + +But, should the Epeira (The Weaving or Garden Spider. Cf. "The Life +of the Spider" by J. Henri Fabre translated by Alexander Teixeira +de Mattos; chapters 9 to 14 and appendix.--Translator's Note.), the +favourite prey, be lacking, must the Pelopaeus therefore give up +foraging? She will stock her warehouses all the same, because any Spider +suits her. There you have discernment, whose elasticity makes up, in +certain circumstances, for the too-great rigidity of instinct. Amid the +innumerable variety of game, the huntress is able to discern between +what is Spider and what is not; and, in this way, she is always prepared +to supply her family, without quitting the domain of her instinct. + +The Hairy Ammophila gives her larva a single caterpillar, a large one, +paralysed by as many pricks of her sting as it has nervous centres in +its thorax and abdomen. Her surgical skill in subduing the monster is +instinct displayed in a form which makes short work of any inclination +to see in it an acquired habit. In an art that can leave no one to +practise it in the future unless that one be perfect at the outset, of +what avail are happy chances, atavistic tendencies, the mellowing hand +of time? But the grey caterpillar, sacrificed one day, may be succeeded +on another day by a green, yellow or striped caterpillar. There you have +discernment, which is quite capable of recognizing the regulation prey +under very diverse garbs. + +The Megachiles build their honey-jars with disks cut out of leaves; +certain Anthidia make felted cotton wallets; others fashion pots out +of resin. There you have instinct. Will any rash mind ever conceive the +singular idea that the Leaf-cutter might very well have started working +in cotton, that the cotton-wool-worker once thought or will one +day think of cutting disks out of the leaves of the lilac- and the +rose-tree, that the resin-kneader began with clay? Who would dare to +indulge in any such theories? Each Bee has her art, her medium, to which +she strictly confines herself. The first has her leaves; the second +her wadding; the third her resin. None of these guilds has ever changed +trades with another; and none ever will. There you have instinct, +keeping the workers to their specialities. There are no innovations +in their workshops, no recipes resulting from experiment, no ingenious +devices, no progress from indifferent to good, from good to excellent. +To-day's method is the facsimile of yesterday's; and to-morrow will know +no other. + +But, though the manufacturing-process is invariable, the raw material is +subject to change. The plant that supplies the cotton differs in species +according to the locality; the bush out of whose leaves the pieces will +be cut is not the same in the various fields of operation; the tree that +provides the resinous putty may be a pine, a cypress, a juniper, a +cedar or a spruce, all very different in appearance. What will guide the +insect in its gleaning? Discernment. + +These, I think, are sufficient details of the fundamental distinction +to be drawn in the insect's mentality; the distinction, that is, between +instinct and discernment. If people confuse these two provinces, as they +nearly always do, any understanding becomes impossible; the last glimmer +of light disappears behind the clouds of interminable discussions. From +an industrial point of view, let us look upon the insect as a worker +thoroughly versed from birth in a craft whose essential principles never +vary; let us grant that unconscious worker a gleam of intelligence +which will permit it to extricate itself from the inevitable conflict of +attendant circumstances; and I think that we shall have come as near to +the truth as the state of our knowledge will allow for the moment. + +Having thus assigned a due share both to instinct and the aberrations +of instinct when the course of its different phases is disturbed, let +us see what discernment is able to do in the selection of a site for +the nest and materials for building it; and, leaving the Pelopaeus, upon +whom it is useless to dwell any longer, let us consider other examples, +picked from among those richest in variations. + +The Mason-bee of the Sheds (Chalicodoma rufitarsis, PEREZ) well deserves +the name which I have felt justified in giving her from her habits: she +settles in numerous colonies in our sheds, on the lower surface of the +tiles, where she builds huge nests which endanger the solidity of the +roof. Nowhere does the insect display a greater zeal for work than in +one of these colossal cities, an estate which is constantly increasing +as it passes down from one generation to another; nowhere does it find a +better workshop for the exercise of its industry. Here it has plenty of +room: a quiet resting-place, sheltered from damp and from excess of heat +or cold. + +But the spacious domain under the tiles is not within the reach of all: +sheds with free access and the proper sunny aspect are pretty rare. +These sites fall only to the favoured of fortune. Where will the others +take up their quarters? More or less everywhere. Without leaving the +house in which I live, I can enumerate stone, wood, glass, metal, paint +and mortar as forming the foundation of the nests. The green-house with +its furnace heat in the summer and its bright light, equalling that +outside, is fairly well-frequented. The Mason-bee hardly ever fails to +build there each year, in squads of a few dozen apiece, now on the glass +panes, now on the iron bars of the framework. Other little swarms settle +in the window embrasures, under the projecting ledge of the front door +or in the cranny between the wall and an open shutter. Others again, +being perhaps of a morose disposition, flee society and prefer to work +in solitude, one in the inside of a lock or of a pipe intended to carry +the rain-water from the leads; another in the mouldings of the doors and +windows or in the crude ornamentation of the stone-work. In short, +the house is made use of all round, provided that the shelter be an +out-of-door one; for observe that the enterprising invader, unlike +the Pelopaeus, never penetrates inside our dwellings. The case of +the conservatory is an exception more apparent than real: the glass +building, standing wide open throughout the summer, is to the Mason-bee +but a shed a little lighter than the others. There is nothing here to +arouse the distrust with which anything indoors or shut up inspires +her. To build on the threshold of an outer door, or to usurp its lock, +a hiding-place to her fancy, is all that she allows herself; to go any +farther is an adventure repugnant to her taste. + +Lastly, in the case of all these dwellings, the Mason-bee is man's free +tenant; her industry makes use of the products of our own industry. Can +she have no other establishments? She has, beyond a doubt; she possesses +some constructed on the ancient plan. On a stone the size of a man's +fist, protected by the shelter of a hedge, sometimes even on a pebble +in the open air, I see her building now groups of cells as large as a +walnut, now domes emulating in size, shape and solidity those of her +rival, the Mason-bee of the Walls. + +The stone support is the most frequent, though not the only one. I have +found nests, but sparsely inhabited it is true, on the trunks of trees, +in the seams of the rough bark of oaks. Among those whose support was +a living plant, I will mention two that stand out above all the others. +The first was built in the lobe of a torch-thistle as thick as my leg; +the second rested on a stalk of the opuntia, the Indian fig. Had the +fierce armour of these two stout cactuses attracted the attention of the +insect, which looked upon their tufts of spikes as furnishing a system +of defence for its nest? Perhaps so. In any case, the attempt was not +imitated; I never saw another installation of the kind. There is one +definite conclusion to be drawn from my two discoveries. Despite the +oddity of their structure, which is unparalleled among the local flora, +the two American importations did not compel the insect to go through an +apprenticeship of groping and hesitation. The one which found itself in +the presence of those novel growths, and which was perhaps the first of +its race to do so, took possession of their lobes and stalks just as it +would have done of a familiar site. From the start, the fleshy plants +from the New World suited it as well as the trunk of a native tree. + +The Mason-bee of the Pebbles (Chalicodoma parietina) has none of this +elasticity in the choice of a site. In her case, the smooth stone of the +parched uplands is the almost invariable foundation of her structures. +Elsewhere, under a less clement sky, she prefers the support of a +wall, which protects the nest against the prolonged snows. Lastly, the +Mason-bee of the Shrubs (Chalicodoma rufescens, PEREZ) fixes her ball of +clay to a twig of any ligneous plant, from the thyme, the rock-rose and +the heath to the oak, the elm and the pine. The list of the sites that +suit her would almost form a complete catalogue of the ligneous flora. + +The variety of places wherein the insect instals itself, so eloquent of +the part played by discernment in their selection, becomes still more +remarkable when it is accompanied by a corresponding variety in the +architecture of the cells. This is more particularly the case with +the Three-horned Osmia, who, as she uses clayey materials very easily +affected by the rain, requires, like the Pelopaeus, a dry shelter for +her cells, a shelter which she finds ready-made and uses just as it is, +after a few touches by way of sweeping and cleansing. The homes which I +see her adopt are especially the shells of Snails that have died under +the stone-heaps and in the low, unmortared walls which support the +cultivated earth of the hills in shelves or terraces. The use of +Snail-shells is accompanied by the no less active use of the old cells +of both the Mason-bee of the Sheds and of certain Anthophorae (A. +pilipes, A. parietina and A. personata). + +We must not forget the reed, which is highly appreciated when--a rare +find--it appears under the requisite conditions. In its natural state, +the plant with the mighty hollow cylinders is of no possible use to the +Osmia, who knows nothing of the art of perforating a woody wall. The +gallery of an internode has to be wide open before the insect can +take possession of it. Also, the clean-cut stump must be horizontal, +otherwise the rain would soften the fragile edifice of clay and soon lay +it low; also, the stump must not be lying on the ground and must be kept +at some distance from the dampness of the soil. We see therefore that, +without the intervention of man, involuntary in the vast majority of +cases and deliberate only on the experimenter's part, the Osmia would +hardly ever find a reed-stump suited to the installation of her family. +It is to her a casual acquisition, a home unknown to her race before +men took it into their heads to cut reeds and make them into hurdles for +drying figs in the sun. + +How did the work of man's pruning-knife bring about the abandonment of +the natural lodging? How was the spiral staircase of the Snail-shell +replaced by the cylindrical gallery of the reed? Was the change from one +kind of house to another effected by gradual transitions, by attempts +made, abandoned, resumed, becoming more and more definite in their +results as generation succeeded generation? Or did the Osmia, finding +the cut reed that answered her requirements, instal herself there +straightway, scorning her ancient dwelling, the Snail-shell? These +questions called for a reply; and they have received one. Let us +describe how things happened. + +Near Serignan are some great quarries of coarse limestone, +characteristic of the miocene formation of the Rhone valley. These +have been worked for many generations. The ancient public buildings of +Orange, notably the colossal frontage of the theatre whither all the +intellectual world once flocked to hear Sophocles' "Oedipus Tyrannus," +derive most of their material from these quarries. Other evidence +confirms what the similarity of the hewn stone tells us. Among the +rubbish that fills up the spaces between the tiers of seats, they +occasionally discover the Marseilles obol, a bit of silver stamped +with the four-spoked wheel, or a few bronze coins bearing the effigy of +Augustus or Tiberius. Scattered also here and there among the monuments +of antiquity are heaps of refuse, accumulations of broken stones +in which various Hymenoptera, including the Three-horned Osmia in +particular, take possession of the dead Snail-shell. + +The quarries form part of an extensive plateau which is so arid as to be +nearly deserted. In these conditions, the Osmia, at all times faithful +to her birth-place, has little or no need to emigrate from her heap of +stones and leave the shell for another dwelling which she would have +to go and seek at a distance. Since there are heaps of stone there, she +probably has no other dwelling than the Snail-shell. Nothing tells us +that the present-day generations are not descended in the direct line +from the generations contemporary with the quarryman who lost his as or +his obol at this spot. All the circumstances seem to point to it: the +Osmia of the quarries is an inveterate user of Snail-shells; so far as +heredity is concerned, she knows nothing whatever of reeds. Well, we +must place her in the presence of these new lodgings. + +I collect during the winter about two dozen well-stocked Snail-shells +and instal them in a quiet corner of my study, as I did at the time of +my enquiries into the distribution of the sexes. The little hive with +its front pierced with forty holes has bits of reed fitted to it. At the +foot of the five rows of cylinders I place the inhabited shells and +with these I mix a few small stones, the better to imitate the natural +conditions. I add an assortment of empty Snail-shells, after carefully +cleaning the interior so as to make the Osmia's stay more pleasant. When +the time comes for nest-building, the stay-at-home insect will have, +close beside the house of its birth, a choice of two habitations: the +cylinder, a novelty unknown to its race; and the spiral staircase, the +ancient ancestral home. + +The nests were finished at the end of May and the Osmiae began to answer +my list of questions. Some, the great majority, settled exclusively +in the reeds; the others remained faithful to the Snail-shell or else +entrusted their eggs partly to the spirals and partly to the cylinders. +With the first, who were the pioneers of cylindrical architecture, there +was no hesitation that I could perceive: after exploring the stump of +reed for a time and recognizing it as serviceable, the insect +instals itself there and, an expert from the first touch, without +apprenticeship, without groping, without any tendencies bequeathed by +the long practice of its predecessors, builds its straight row of cells +on a very different plan from that demanded by the spiral cavity of the +shell which increases in size as it goes on. + +The slow school of the ages, the gradual acquisitions of the past, +the legacies of heredity count for nothing therefore in the Osmia's +education. Without any novitiate on its own part or that of its +forebears, the insect is versed straight away in the calling which it +has to pursue; it possesses, inseparable from its nature, the qualities +demanded by its craft: some which are invariable and belong to the +domain of instinct; others, flexible, belonging to the province of +discernment. To divide a free lodging into chambers by means of mud +partitions; to fill those chambers with a heap of pollen-flour, with a +few sups of honey in the central part where the egg is to lie; in short, +to prepare board and lodging for the unknown, for a family which the +mothers have never seen in the past and will never see in the future: +this, in its essential features, is the function of the Osmia's +instinct. Here, everything is harmoniously, inflexibly, permanently +preordained; the insect has but to follow its blind impulse to attain +the goal. But the free lodging offered by chance varies exceedingly in +hygienic conditions, in shape and in capacity. Instinct, which does +not choose, which does not contrive, would, if it were alone, leave +the insect's existence in peril. To help her out of her predicament, +in these complex circumstances, the Osmia possesses her little stock of +discernment, which distinguishes between the dry and the wet, the solid +and the fragile, the sheltered and the exposed; which recognizes the +worth or the worthlessness of a site and knows how to sprinkle it with +cells according to the size and shape of the space at disposal. Here, +slight industrial variations are necessary and inevitable; and the +insect excels in them without any apprenticeship, as the experiment with +the native Osmia of the quarries has just proved. + +Animal resources have a certain elasticity, within narrow limits. What +we learn from the animals' industry at a given moment is not always the +full measure of their skill. They possess latent powers held in reserve +for certain emergencies. Long generations can succeed one another +without employing them; but, should some circumstance require it, +suddenly those powers burst forth, free of any previous attempts, +even as the spark potentially contained in the flint flashes forth +independently of all preceding gleams. Could one who knew nothing of the +Sparrow but her nest under the eaves suspect the ball-shaped nest at the +top of a tree? Would one who knew nothing of the Osmia save her home +in the Snail-shell expect to see her accept as her dwelling a stump +of reed, a paper funnel, a glass tube? My neighbour the Sparrow, +impulsively taking it into her head to leave the roof for the +plane-tree, the Osmia of the quarries, rejecting her natal cabin, the +spiral of the shell, for my cylinder, alike show us how sudden and +spontaneous are the industrial variations of animals. + + + + +CHAPTER 7. ECONOMY OF ENERGY. + +What stimulus does the insect obey when it employs the reserve powers +that slumber in its race? Of what use are its industrial variations? The +Osmia will yield us her secret with no great difficulty. Let us examine +her work in a cylindrical habitation. I have described in full detail, +in the foregoing pages, the structure of her nests when the dwelling +adopted is a reed-stump or any other cylinder; and I will content myself +here with recapitulating the essential features of that nest-building. + +We must first distinguish three classes of reeds according to their +diameter: the small, the medium-sized and the large. I call small those +whose narrow width just allows the Osmia to go about her household +duties without discomfort. She must be able to turn where she stands +in order to brush her abdomen and rub off its load of pollen, after +disgorging the honey in the centre of the heap of flour already +collected. If the width of the tube does not admit of this operation, +if the insect is obliged to go out and then come in again backwards in +order to place itself in a favourable posture for the discharge of the +pollen, then the reed is too narrow and the Osmia is rather reluctant +to accept it. The middle-sized reeds and a fortiori the large ones leave +the victualler entire liberty of action; but the former do not exceed +the width of a cell, a width agreeing with the bulk of the future +cocoon, whereas the latter, with their excessive diameter, require more +than one chamber on the same floor. + +When free to choose, the Osmia settles by preference in the small reeds. +Here, the work of building is reduced to its simplest expression and +consists in dividing the tube by means of earthen partitions into a +straight row of cells. Against the partition forming the back wall of +the preceding cell the mother places first a heap of honey and pollen; +next, when the portion is seen to be enough, she lays an egg in the +centre of it. Then and then only she resumes her plasterer's work +and marks out the length of the new cell with a mud partition. This +partition in its turn serves as the rear-wall of another chamber, which +is first victualled and then closed; and so on until the cylinder is +sufficiently colonized and receives a thick terminal stopper at +its orifice. In a word, the chief characteristic of this method of +nest-building, the roughest of all, is that the partition in front is +not undertaken so long as the victualling is still incomplete, or, in +other words, that the provisions and the egg are deposited before the +Bee sets to work on the partition. + +At first sight, this latter detail hardly deserves attention: is it +not right to fill the pot before we put a lid on? The Osmia who owns a +medium-sized reed is not at all of this opinion; and other plasterers +share her views, as we shall see when we watch the Odynerus building +her nest. (A genus of Mason-wasps, the essays on which have not yet been +translated into English.--Translator's Note.) Here we have an excellent +illustration of one of those latent powers held in reserve for +exceptional occasions and suddenly brought into play, although often +very far removed from the insect's regular methods. If the reed, without +being of inordinate width from the point of view of the cocoon, is +nevertheless too spacious to afford the Bee a suitable purchase against +the wall at the moment when she is disgorging honey and brushing off her +load of pollen; the Osmia altogether changes the order of her work; she +sets up the partition first and then does the victualling. + +All round the inside of the tube she places a ring of mud, which, as the +result of her constant visits to the mortar, ends by becoming a complete +diaphragm minus an orifice at the side, a sort of round dog-hole, just +large enough for the insect to pass through. When the cell is thus +marked out and almost wholly closed, the Osmia attends to the storing of +her provisions and the laying of her eggs. Steadying herself against the +margin of the hole at one time with her fore-legs and at another with +her hind-legs, she is able to empty her crop and to brush her abdomen; +by pressing against it, she obtains a foothold for her little efforts +in these various operations. When the tube was narrow, the outer wall +supplied this foothold and the earthen partition was postponed until the +heap of provisions was completed and surmounted by the egg; but in +the present case the passage is too wide and would leave the insect +floundering helplessly in space, so the partition with its serving-hatch +takes precedence of the victuals. This method is a little more expensive +than the other, first in materials, because of the diameter of the reed, +and secondly in time, if only because of the dog-hole, a delicate piece +of mortar-work which is too soft at first and cannot be used until it +has dried and become harder. Therefore the Osmia, who is sparing of her +time and strength, accepts medium-sized reeds only when there are no +small ones available. + +The large tubes she will use only in grave emergencies and I am unable +to state exactly what these exceptional circumstances are. Perhaps she +decides to make use of those roomy dwellings when the eggs have to be +laid at once and there is no other shelter in the neighbourhood. While +my cylinder-hives gave me plenty of well-filled reeds of the first and +second class, they provided me with but half-a-dozen at most of the +third, notwithstanding my precaution to furnish the apparatus with a +varied assortment. + +The Osmia's repugnance to big cylinders is quite justified. The work in +fact is longer and more costly when the tubes are wide. An inspection of +a nest constructed under these conditions is enough to convince us. It +now consists not of a string of chambers obtained by simple transverse +partitions, but of a confused heap of clumsy, many-sided compartments, +standing back to back, with a tendency to group themselves in storeys +without succeeding in doing so, because any regular arrangement would +mean that the ceilings possessed a span which it is not in the builder's +power to achieve. The edifice is not a geometrical masterpiece and it +is even less satisfactory from the point of view of economy. In the +previous constructions, the sides of the reed supplied the greater part +of the walls and the work was limited to one partition for each cell. +Here, except at the actual periphery, where the tube itself supplies a +foundation, everything has to be obtained by sheer building: the floor, +the ceiling, the walls of the many-sided compartment are one and all +made of mortar. The structure is almost as costly in materials as that +of the Chalicodoma or the Pelopaeus. + +It must be pretty difficult, too, when one thinks of its irregularity. +Fitting as best she can the projecting angles of the new cell into the +recessed corners of the cell already built, the Osmia runs up walls +more or less curved, upright or slanting, which intersect one another at +various points, so that each compartment requires a new and +complicated plan of construction, which is very different from the +circular-partition style of architecture, with its row of parallel +dividing-disks. Moreover, in this composite arrangement, the size of the +recesses left available by the earlier work to some extent decides +the assessment of the sexes, for, according to the dimensions of those +recesses, the walls erected take in now a larger space, the home of +a female, and now a smaller space, the home of a male. Roomy quarters +therefore have a double drawback for the Osmia: they greatly increase +the outlay in materials; and also they establish in the lower layers, +among the females, males who, because of their earlier hatching, would +be much better placed near the mouth of the nest. I am convinced of it: +if the Osmia refuses big reeds and accepts them only in the last resort, +when there are no others, it is because she objects to additional labour +and to the mixture of the sexes. + +The Snail-shell, then, is but an indifferent home for her, which she +is quite ready to abandon should a better offer. Its expanding cavity +represents an average between the favourite small cylinder and the +unpopular large cylinder, which is accepted only when there is no other +obtainable. The first whorls of the spiral are too narrow to be of use +to the Osmia, but the middle ones have the right diameter for cocoons +arranged in single file. Here things happen as in a first-class reed, +for the helical curve in no way affects the method of structure employed +for a rectilinear series of cells. Circular partitions are erected at +the required distances, with or without a serving-hatch, according to +the diameter. These mark out the first cells, one after the other, which +are reserved solely for the females. Then comes the last whorl, which +is much too wide for a single row of cells; and here we once more find, +exactly as in a wide reed, a costly profusion of masonry, an irregular +arrangement of the cells and a mixture of the sexes. + +Having said so much, let us go back to the Osmia of the quarries. Why, +when I offer them simultaneously Snail-shells and reeds of a suitable +size, do the old frequenters of the shells prefer the reeds, which in +all probability have never before been utilized by their race? Most of +them scorn the ancestral dwelling and enthusiastically accept my reeds. +Some, it is true, take up their quarters in the Snail-shell; but even +among these a goodly number refuse my new shells and return to their +birth-place, the old Snail-shell, in order to utilize the family +property, without much labour, at the cost of a few repairs. Whence, +I ask, comes this general preference for the cylinder, never used +hitherto? The answer can be only this: of two lodgings at her disposal +the Osmia selects the one that provides a comfortable home at a minimum +outlay. She economizes her strength when restoring an old nest; she +economizes it when replacing the Snail-shell by the reed. + +Can animal industry, like our own, obey the law of economy, the sovran +law that governs our industrial machine even as it governs, at least to +all appearances, the sublime machine of the universe? Let us go +deeper into the question and bring other workers into evidence, those +especially who, better equipped perhaps and at any rate better fitted +for hard work, attack the difficulties of their trade boldly and look +down upon alien establishments with scorn. Of this number are the +Chalicodomae, the Mason-bees proper. + +The Mason-bee of the Pebbles does not make up her mind to build a +brand-new dome unless there be a dearth of old and not quite dilapidated +nests. The mothers, sisters apparently and heirs-at-law to the domain, +dispute fiercely for the ancestral abode. The first who, by sheer brute +force, takes possession of the dome, perches upon it and, for long +hours, watches events while polishing her wings. If some claimant puts +in an appearance, forthwith the other turns her out with a volley of +blows. In this way the old nests are employed so long as they have not +become uninhabitable hovels. + +Without being equally jealous of the maternal inheritance, the Mason-bee +of the Sheds eagerly uses the cells whence her generation issued. The +work in the huge city under the eaves begins thus: the old cells, +of which, by the way, the good-natured owner yields a portion to +Latreille's Osmia and to the Three-horned Osmia alike, are first made +clean and wholesome and cleared of broken plaster and then provisioned +and shut. When all the accessible chambers are occupied, the actual +building begins with a new stratum of cells upon the former edifice, +which becomes more and more massive from year to year. + +The Mason-bee of the Shrubs, with her spherical nests hardly larger than +walnuts, puzzled me at first. Does she use the old buildings or does she +abandon them for good? To-day perplexity makes way for certainty: she +uses them very readily. I have several times surprised her lodging +her family in the empty rooms of a nest where she was doubtless born +herself. Like her kinswoman of the Pebbles, she returns to the native +dwelling and fights for its possession. Also, like the dome-builder, +she is an anchorite and prefers to cultivate the lean inheritance alone. +Sometimes, however, the nest is of exceptional size and harbours a crowd +of occupants, who live in peace, each attending to her business, as in +the colossal hives in the sheds. Should the colony be at all numerous +and the estate descend to two or three generations in succession, with a +fresh layer of masonry each year, the normal walnut-sized nest becomes +a ball as large as a man's two fists. I have gathered on a pine-tree +a nest of the Mason-bee of the Shrubs that weighed a kilogram (2.205 +pounds avoirdupois.--Translator's Note.) and was the size of a child's +head. A twig hardly thicker than a straw served as its support. The +casual sight of that lump swinging over the spot on which I had sat down +made me think of the mishap that befell Garo. (The hero of La Fontaine's +fable, "Le Gland et la Citrouille," who wondered why acorns grew on such +tall trees and pumpkins on such low vines, until he fell asleep under +one of the latter and a pumpkin dropped upon his nose.--Translator's +Note.) If such nests were plentiful in the trees, any one seeking the +shade would run a serious risk of having his head smashed. + +After the Masons, the Carpenters. Among the guild of wood-workers, the +most powerful is the Carpenter-bee (Xylocopa violacea (Cf. "The Life +of the Spider": chapter 1.--Translator's Note.)), a very large Bee of +formidable appearance, clad in black velvet with violet-coloured wings. +The mother gives her larvae as a dwelling a cylindrical gallery which +she digs in rotten wood. Useless timber lying exposed to the air, +vine-poles, large logs of fire-wood seasoning out of doors, heaped up +in front of the farmhouse porch, stumps of trees, vine-stocks and big +branches of all kinds are her favourite building-yards. A solitary and +industrious worker, she bores, bit by bit, circular passages the width +of one's thumb, as clear-cut as though they were made with an auger. +A heap of saw-dust accumulates on the ground and bears witness to the +severity of the task. Usually, the same aperture is the entrance to +two or three parallel corridors. With several galleries there is +accommodation for the entire laying, though each gallery is quite +short; and the Bee thus avoids those long series which always create +difficulties when the moment of hatching arrives. The laggards and the +insects eager to emerge are less likely to get in each other's way. + +After obtaining the dwelling, the Carpenter-bee behaves like the Osmia +who is in possession of a reed. Provisions are collected, the egg is +laid and the chamber is walled in front with a saw-dust partition. The +work is pursued in this way until the two or three passages composing +the house are completely stocked. Heaping up provisions and erecting +partitions are an invariable feature of the Xylocopa's programme; no +circumstance can release the mother from the duty of providing for the +future of her family, in the matter both of ready-prepared food and of +separate compartments for the rearing of each larva. It is only in +the boring of the galleries, the most laborious part of the work, that +economy can occasionally be exercised by a piece of luck. Well, is the +powerful Carpenter, all unheeding of fatigue, able to take advantage of +such fortunate occasions? Does she know how to make use of houses which +she has not tunnelled herself? Why, yes: a free lodging suits her just +as much as it does the various Mason-bees. She knows as well as they the +economic advantages of an old nest that is still in good condition: she +settles down, as far as possible, in her predecessors' galleries, after +freshening up the sides with a superficial scraping. And she does better +still. She readily accepts lodgings which have never known a drill, no +matter whose. The stout reeds used in the trellis-work that supports the +vines are valuable discoveries, providing as they do sumptuous galleries +free of cost. No preliminary work or next to none is required with +these. Indeed, the insect does not even trouble to make a side-opening, +which would enable it to occupy the cavity contained within two nodes; +it prefers the opening at the end cut by man's pruning-knife. If the +next partition be too near to give a chamber of sufficient length, the +Xylocopa destroys it, which is easy work, not to be compared with the +labour of cutting an entrance through the side. In this way, a spacious +gallery, following on the short vestibule made by the pruning-knife, is +obtained with the least possible expenditure of energy. + +Guided by what was happening on the trellises, I offered the black Bee +the hospitality of my reed-hives. From the very beginning, the insect +gladly welcomed my advances; each spring, I see it inspect my rows of +cylinders, pick out the best ones and instal itself there. Its work, +reduced to a minimum by my intervention, is limited to the partitions, +the materials for which are obtained by scraping the inner sides of the +reed. + +As first-rate joiners, next to the Carpenter-bees come the Lithurgi, +of whom my district possesses two species: L. cornutus, FAB., and L. +chrysurus, BOY. By what aberration of nomenclature was the name of +Lithurgus, a worker in stone, given to insects which work solely +in wood? I have caught the first, the stronger of the two, digging +galleries in a large block of oak that served as an arch for a +stable-door; I have always found the second, who is more widely +distributed, settling in dead wood--mulberry, cherry, almond, +poplar--that was still standing. Her work is exactly the same as the +Xylocopa's, on a smaller scale. A single entrance-hole gives access +to three or four parallel galleries, assembled in a serried group; +and these galleries are subdivided into cells by means of saw-dust +partitions. Following the example of the big Carpenter-bee, Lithurgus +chrysurus knows how to avoid the laborious work of boring, when occasion +offers: I find her cocoons lodged almost as often in old dormitories +as in new ones. She too has the tendency to economize her strength by +turning the work of her predecessors to account. I do not despair of +seeing her adopt the reed if, one day, when I possess a large enough +colony, I decide to try this experiment on her. I will say nothing about +L. cornutus, whom I only once surprised at her carpentering. + +The Anthophorae, those children of the precipitous earthy banks, show +the same thrifty spirit as the other members of the mining corporation. +Three species, A. parietina, A. personata and A. pilipes, dig long +corridors leading to the cells, which are scattered here and there and +one by one. These passages remain open at all seasons of the year. When +spring comes, the new colony uses them just as they are, provided +that they are well preserved in the clayey mass baked by the sun; it +increases their length if necessary, runs out a few more branches, but +does not decide to start boring in new ground until the old city, which, +with its many labyrinths, resembles some monstrous sponge, is too much +undermined for safety. The oval niches, the cells that open on those +corridors, are also profitably employed. The Anthophora restores their +entrance, which has been destroyed by the insect's recent emergence; +she smooths their walls with a fresh coat of whitewash, after which the +lodging is fit to receive the heap of honey and the egg. When the old +cells, insufficient in number and moreover partly inhabited by diverse +intruders, are all occupied, the boring of new cells begins, in the +extended sections of the galleries, and the rest of the eggs are housed. +In this way, the swarm is settled at a minimum of expense. + +To conclude this brief account, let us change the zoological setting +and, as we have already spoken of the Sparrow, see what he can do as a +builder. The simplest form of his nest is the great round ball of straw, +dead leaves and feathers, in the fork of a few branches. It is costly in +material, but can be set up anywhere, when the hole in the wall or the +shelter of a tile are lacking. What reasons induced him to give up the +spherical edifice? To all seeming, the same reasons that led the +Osmia to abandon the Snail-shell's spiral, which requires a fatiguing +expenditure of clay, in favour of the economical cylinder of the reed. +By making his home in a hole in the wall, the Sparrow escapes the +greater part of his work. Here, the dome that serves as a protection +from the rain and the thick walls that offer resistance to the wind both +become superfluous. A mere mattress is sufficient; the cavity in the +wall provides the rest. The saving is great; and the Sparrow appreciates +it quite as much as the Osmia. + +This does not mean that the primitive art has disappeared, lost through +neglect; it remains an ineffaceable characteristic of the species, ever +ready to declare itself should circumstances demand it. The generations +of to-day are as much endowed with it as the generations of yore; +without apprenticeship, without the example of others, they have within +themselves, in the potential state, the industrial aptitude of their +ancestors. If aroused by the stimulus of necessity, this aptitude will +pass suddenly from inaction to action. When, therefore, the Sparrow +still from time to time indulges in spherical building, this is not +progress on his part, as is sometimes contended; it is, on the contrary, +a retrogression, a return to the ancient customs, so prodigal of labour. +He is behaving like the Osmia who, in default of a reed, makes shift +with a Snail-shell, which is more difficult to utilize but easier to +find. The cylinder and the hole in the wall stand for progress; the +spiral of the Snail-shell and the ball-shaped nest represent the +starting-point. + +I have, I think, sufficiently illustrated the inference which is borne +out by the whole mass of analogous facts. Animal industry manifests a +tendency to achieve the essential with a minimum of expenditure; after +its own fashion, the insect bears witness to the economy of energy. On +the one hand, instinct imposes upon it a craft that is unchangeable +in its fundamental features; on the other hand, it is left a certain +latitude in the details, so as to take advantage of favourable +circumstances and attain the object aimed at with the least possible +expenditure of time, materials and work, the three elements of +mechanical labour. The problem in higher geometry solved by the Hive-bee +is only a particular case--true, a magnificent case,--of this general +law of economy which seems to govern the whole animal world. The wax +cells, with their maximum capacity as against a minimum wall-space, are +the equivalent, with the superaddition of a marvellous scientific skill, +of the Osmia's compartments in which the stonework is reduced to a +minimum through the selection of a reed. The artificer in mud and the +artificer in wax obey the same tendency: they economize. Do they know +what they are doing? Who would venture to suggest it in the case of +the Bee grappling with her transcendental problem? The others, +pursuing their rustic art, are no wiser. With all of them, there is no +calculation, no premeditation, but simply blind obedience to the law of +general harmony. + + + + +CHAPTER 8. THE LEAF-CUTTERS. + +It is not enough that animal industry should be able, to a certain +extent, to adapt itself to casual exigencies when choosing the site of +a nest; if the race is to thrive, something else is required, something +which hide-bound instinct is unable to provide. The Chaffinch, for +instance, introduces a great quantity of lichen into the outer layer of +his nest. This is his method of strengthening the edifice and making +a stout framework in which to place first the bottom mattress of moss, +fine straw and rootlets and then the soft bed of feathers, wool and +down. But, should the time-honoured lichen be lacking, will the bird +refrain from building its nest? Will it forgo the delight of hatching +its brood because it has not the wherewithal to settle its family in the +orthodox fashion? + +No, the chaffinch is not perplexed by so small a matter; he is an expert +in materials, he understands botanical equivalents. In the absence of +the branches of the evernias, he picks the long beards of the usneas, +the wartlike rosettes of the parmelias, the membranes of the stictises +torn away in shreds; if he can find nothing better, he makes shift with +the bushy tufts of the cladonias. As a practical lichenologist, when one +species is rare or lacking in the neighbourhood, he is able to fall back +on others, varying greatly in shape, colour and texture. And, if the +impossible happened and lichen failed entirely, I credit the Chaffinch +with sufficient talent to be able to dispense with it and to build the +foundations of his nest with some coarse moss or other. + +What the worker in lichens tells us the other weavers of textile +materials confirm. Each has his favourite flora, which hardly ever +varies when the plant is easily accessible and which can be supplemented +by plenty of others when it is not. The bird's botany would be worth +examining; it would be interesting to draw up the industrial herbal of +each species. In this connection, I will quote just one instance, so as +not to stray too far from the subject in hand. + +The Red-backed Shrike (Lanius collurio), the commonest variety in my +district, is noteworthy because of his savage mania for forked gibbets, +the thorns in the hedgerows whereon he impales the voluminous contents +of his game-bag--little half-fledged birds, small Lizards, Grasshoppers, +caterpillars, Beetles--and leaves them to get high. To this passion for +the gallows, which has passed unnoticed by the country-folk, at least +in my part, he adds another, an innocent botanical passion, which is +so much in evidence that everybody, down to the youngest bird's-nester, +knows all about it. His nest, a massive structure, is made of hardly +any other materials than a greyish and very fluffy plant, which is +found everywhere among the corn. This is the Filago spathulata of the +botanists; and the bird also makes use, though less frequently, of the +Filago germanica, or common cotton-rose. Both are known in Provencal by +the name herbo dou tarnagas, or Shrike-herb. This popular designation +tells us plainly how faithful the bird is to its plant. To have struck +the agricultural labourer, a very indifferent observer, the Shrike's +choice of materials must be remarkably persistent. + +Have we here a taste that is exclusive? Not in the least. Though +cotton-roses of all species are plentiful on level ground, they become +scarce and impossible to find on the parched hills. The bird, on its +side, is not given to journeys of exploration and takes what it finds to +suit it in the neighbourhood of its tree or hedge. But on arid ground, +the Micropus erectus, or upright micropus, abounds and is a satisfactory +substitute for the Filago so far as its tiny, cottony leaves and its +little fluffy balls of flowers are concerned. True, it is short and +does not lend itself well to weaver's work. A few long sprigs of another +cottony plant, the Helichrysum staechas, or wild everlasting, inserted +here and there, will give body to the structure. Thus does the Shrike +manage when hard up for his favourite materials: keeping to the same +botanical family, he is able to find and employ substitutes among the +fine cotton-clad stalks. + +He is even able to leave the family of the Compositae and to go gleaning +more or less everywhere. Here is the result of my botanizings at the +expense of his nests. We must distinguish between two genera in the +Shrike's rough classification: the cottony plants and the smooth plants. +Among the first, my notes mention the following: Convolvulus cantabrica, +or flax-leaved bindweed; Lotus symmetricus, or bird's-foot trefoil; +Teucrium polium, or poly; and the flowery heads of the Phragmites +communis, or common reed. Among the second are these: Medicago lupulina, +or nonesuch; Trifolium repens, or white clover; Lathyrus pratensis, or +meadow lathyrus; Capsella bursa pastoris, or shepherd's purse; Vicia +peregrina, or broad-podded vetch; Convolvulus arvensis, or small +bindweed; Pterotheca nemausensis, a sort of hawkweed; and Poa pratensis, +or smooth-stalked meadow-grass. When it is downy, the plant forms almost +the whole nest, as is the case with the flax-leaved bindweed; when +smooth, it forms only the framework, destined to support a crumbling +mass of micropus, as is the case with the small bindweed. When making +this collection, which I am far from giving as the birds' complete +herbarium, I was struck by a wholly unexpected detail: of the various +plants, I found only the heads still in bud; moreover, all the sprigs, +though dry, possessed the green colouring of the growing plant, a sign +of swift desiccation in the sun. Save in a few cases, therefore, the +Shrike does not collect the dead and withered remains: it is from the +growing plants that he reaps his harvest, mowing them down with his beak +and leaving the sheaves to dry in the sun before using them. I caught +him one day hopping about and pecking at the twigs of a Biscayan +bindweed. He was getting in his hay, strewing the ground with it. + +The evidence of the Shrike, confirmed by that of all the other +workers--weavers, basket-makers or woodcutters--whom we may care to call +as witnesses, shows us what a large part must be assigned to discernment +in the bird's choice of materials for its nest. Is the insect as highly +gifted? When it works with vegetable matter, is it exclusive in its +tastes? Does it know only one definite plant, its special province? Or +has it, for employment in its manufactures, a varied flora, in which its +discernment exercises a free choice? For answers to these questions we +may look, above all, to the Leaf-cutting Bees, the Megachiles. Reaumur +has told the story of their industry in detail; and I refer the reader +who wishes for further particulars to the master's Memoirs. + +The man who knows how to use his eyes in his garden will observe, some +day or other, a number of curious holes in the leaves of his lilac- and +rose-trees, some of them round, some oval, as if idle but skilful +hands had been at work with the pinking-iron. In some places, there is +scarcely anything but the veins of the leaves left. The author of the +mischief is a grey-clad Bee, a Megachile. For scissors, she has her +mandibles; for compasses, producing now an oval and anon a circle, she +has her eye and the pivot of her body. The pieces cut out are made into +thimble-shaped wallets, destined to contain the honey and the egg: +the larger, oval pieces supply the floor and sides; the smaller, round +pieces are reserved for the lid. A row of these thimbles, placed one on +top of the other, up to a dozen or more, though often there are less: +that is, roughly, the structure of the Leaf-cutter's nest. + +When taken out of the recess in which the mother has manufactured it, +the cylinder of cells seems to be an indivisible whole, a sort of tunnel +obtained by lining with leaves some gallery dug underground. The real +thing does not correspond with its appearance: under the least pressure +of the fingers, the cylinder breaks up into equal sections, which are so +many compartments independent of their neighbours as regards both floor +and lid. This spontaneous break up shows us how the work is done. The +method agrees with those adopted by the other Bees. Instead of a +general scabbard of leaves, afterwards subdivided into compartments by +transverse partitions, the Megachile constructs a string of separate +wallets, each of which is finished before the next is begun. + +A structure of this sort needs a sheath to keep the pieces in place +while giving them the proper shape. The bag of leaves, in fact, as +turned out by the worker, lacks stability; its numerous pieces, not +glued together, but simply placed one after the other, come apart and +give way as soon as they lose the support of the tunnel that keeps them +united. Later, when it spins its cocoon, the larva infuses a little +of its fluid silk into the gaps and solders the pieces to one another, +especially the inner ones, so much so that the insecure bag in due +course becomes a solid casket whose component parts it is no longer +possible to separate entirely. + +The protective sheath, which is also a framework, is not the work of +the mother. Like the great majority of the Osmiae, the Megachiles do not +understand the art of making themselves a home straight away: they +want a borrowed lodging, which may vary considerably in character. +The deserted galleries of the Anthophorae, the burrows of the fat +Earth-worms, the tunnels bored in the trunks of trees by the larva of +the Cerambyx-beetle (The Capricorn, the essay on which has not yet been +published in English.--Translator's Note.), the ruined dwellings of +the Mason-bee of the Pebbles, the Snail-shell nests of the Three-horned +Osmia, reed-stumps, when these are handy, and crevices in the walls +are all so many homes for the Leaf-cutters, who choose this or that +establishment according to the tastes of their particular genus. + +For the sake of clearness, let us cease generalizing and direct our +attention to a definite species. I first selected the White-girdled +Leaf-cutter (Megachile albocincta, PEREZ), not on account of any +exceptional peculiarities, but solely because this is the Bee most +often mentioned in my notes. Her customary dwelling is the tunnel of an +Earth-worm opening on some clay bank. Whether perpendicular or slanting, +this tunnel runs down to an indefinite depth, where the climate would be +too damp for the Bee. Besides, when the time comes for the hatching of +the adult insect, its emergence would be fraught with peril if it had +to climb up from a deep pit through crumbling rubbish. The Leaf-cutter, +therefore, uses only the front portion of the Worm's gallery, two +decimetres at most. (7.8 inches.--Translator's Note.) What is to be done +with the rest of the tunnel? It is an ascending shaft, tempting to an +enemy; and some underground ravager might come this way and destroy the +nest by attacking the row of cells at the back. + +The danger is foreseen. Before fashioning her first honey-bag, the +Bee blocks the passage with a strong barricade composed of the only +materials used in the Leaf-cutter's guild. Fragments of leaves are +piled up in no particular order, but in sufficient quantities to make +a serious obstacle. It is not unusual to find in the leafy rampart some +dozens of pieces rolled into screws and fitting into one another like +a stack of cylindrical wafers. For this work of fortification, artistic +refinement seems superfluous; at any rate, the pieces of leaves are for +the most part irregular. You can see that the insect has cut them out +hurriedly, unmethodically and on a different pattern from that of the +pieces intended for the cells. + +I am struck with another detail in the barricade. Its constituents +are taken from stout, thick, strong-veined leaves. I recognize young +vine-leaves, pale-coloured and velvety; the leaves of the whitish +rock-rose (Cistus albidus), lined with a hairy felt; those of the +holm-oak, selected among the young and bristly ones; those of the +hawthorn, smooth but tough; those of the cultivated reed, the only one +of the Monocotyledones exploited, as far as I know, by the Megachiles. +In the construction of cells, on the other hand, I see smooth leaves +predominating, notably those of the wild briar and of the common acacia, +the robinia. It would appear, therefore, that the insect distinguishes +between two kinds of materials, without being an absolute purist and +sternly excluding any sort of blending. The very much indented leaves, +whose projections can be completely removed with a dexterous snip of +the scissors, generally furnish the various layers of the barricade; the +little robinia-leaves, with their fine texture and their unbroken edges, +are better suited to the more delicate work of the cells. + +A rampart at the back of the Earth-worm's shaft is a wise precaution and +the Leaf-cutter deserves all credit for it; only it is a pity for the +Megachiles' reputation that this protective barrier often protects +nothing at all. Here we see, under a new guise, that aberration of +instinct of which I gave some examples in an earlier chapter. My notes +contain memoranda of various galleries crammed with pieces of leaves +right up to the orifice, which is on a level with the ground, and +entirely devoid of cells, even of an unfinished one. These were +ridiculous fortifications, of no use whatever; and yet the Bee treated +the matter with the utmost seriousness and took infinite pains over her +futile task. One of these uselessly barricaded galleries furnished me +with some hundred pieces of leaves arranged like a stack of wafers; +another gave me as many as a hundred and fifty. For the defence of a +tenanted nest, two dozen and even fewer are ample. Then what was the +object of the Leaf-cutter's ridiculous pile? + +I wish I could believe that, seeing that the place was dangerous, she +made her heap bigger so that the rampart might be in proportion to +the danger. Then, perhaps, at the moment of starting on the cells, she +disappeared, the victim of an accident, blown out of her course by +a gust of wind. But this line of defence is not admissible in the +Megachile's case. The proof is palpable: the galleries aforesaid are +barricaded up to the level of the ground; there is no room, absolutely +none, to lodge even a single egg. What was her object, I ask again, when +she persisted in obstinately piling up her wafers? Has she really an +object? + +I do not hesitate to say no. And my answer is based upon what the Osmiae +taught me. I have described above how the Three-horned Osmia, towards +the end of her life, when her ovaries are depleted, expends on useless +operations such energy as remains to her. Born a worker, she is bored by +the inactivity of retirement; her leisure requires an occupation. Having +nothing better to do, she sets up partitions; she divides a tunnel +into cells that will remain empty; she closes with a thick plug reeds +containing nothing. Thus is the modicum of strength of her decline +exhausted in vain labours. The other Builder-bees behave likewise. I see +Anthidia laboriously provide numerous bales of cotton to stop galleries +wherein never an egg was laid; I see Mason-bees build and then +religiously close cells that will remain unvictualled and uncolonized. + +The long and useless barricades then belong to the last hours of the +Megachile's life, when the eggs are all laid; the mother, whose ovaries +are exhausted, persists in building. Her instinct is to cut out and heap +up pieces of leaves; obeying this impulse, she cuts out and heaps up +even when the supreme reason for this labour ceases. The eggs are no +longer there, but some strength remains; and that strength is expended +as the safety of the species demanded in the beginning. The wheels of +action go on turning in the absence of the motives for action; they +continue their movement as though by a sort of acquired velocity. What +clearer proof can we hope to find of the unconsciousness of the animal +stimulated by instinct? + +Let us return to the Leaf-cutter's work under normal conditions. +Immediately after a protective barrier comes the row of cells, which +vary considerably in number, like those of the Osmia in her reed. +Strings of about a dozen are rare; the most frequent consist of five or +six. No less subject to variation is the number of pieces joined to make +a cell: pieces of two kinds, some, the oval ones, forming the honey-pot; +others, the round ones, serving as a lid. I count, on an average, eight +to ten pieces of the first kind. Though all cut on the pattern of an +ellipse, they are not equal in dimensions and come under two categories. +The larger, outside ones are each of them almost a third of the +circumference and overlap one another slightly. Their lower end bends +into a concave curve to form the bottom of the bag. Those inside, which +are considerably smaller, increase the thickness of the sides and fill +up the gaps left by the first. + +The Leaf-cutter therefore is able to use her scissors according to the +task before her: first, the large pieces, which help the work forward, +but leave empty spaces; next, the small pieces, which fit into the +defective portions. The bottom of the cell particularly comes in for +after-touches. As the natural curve of the larger pieces is not enough +to provide a cup without cracks in it, the Bee does not fail to improve +the work with two or three small oval pieces applied to the imperfect +joins. + +Another advantage results from the snippets of unequal size. The three +or four outer pieces, which are the first placed in position, being +the longest of all, project beyond the mouth, whereas the next, being +shorter, do not come quite up to it. A brim is thus obtained, a ledge +on which the round disks of the lid rest and are prevented from touching +the honey when the Bee presses them into a concave cover. In other +words, at the mouth the circumference comprises only one row of leaves; +lower down it takes two or three, thus restricting the diameter and +securing an hermetic closing. + +The cover of the pot consists solely of round pieces, very nearly alike +and more or less numerous. Sometimes I find only two, sometimes I count +as many as ten, closely stacked. At times, the diameter of these pieces +is of an almost mathematical precision, so much so that the edges of the +disk rest upon the ledge. No better result would be obtained had they +been cut out with the aid of compasses. At times, again, the piece +projects slightly beyond the mouth, so that, to enter, it has to be +pressed down and curved cupwise. There is no variation in the diameter +of the first pieces placed in position, those nearest to the honey. +They are all of the same size and thus form a flat cover which does not +encroach on the cell and will not afterwards interfere with the larva, +as a convex ceiling would. The subsequent disks, when the pile is +numerous, are a little larger; they only fit the mouth by yielding to +pressure and becoming concave. The Bee seems to make a point of this +concavity, for it serves as a mould to receive the curved bottom of the +next cell. + +When the row of cells is finished, the task still remains of blocking up +the entrance to the gallery with a safety-stopper similar to the earthen +plug with which the Osmia closes her reeds. The Bee then returns to the +free and easy use of the scissors which we noticed at the beginning when +she was fencing off the back part of the Earth-worm's too deep burrow; +she cuts out of the foliage irregular pieces of different shapes and +sizes and often retaining their original deeply-indented margins; and +with all these pieces, very few of which fit at all closely the orifice +to be blocked, she succeeds in making an inviolable door, thanks to the +huge number of layers. + +Let us leave the Leaf-cutter to finish depositing her eggs in other +galleries, which will be colonized in the same manner, and consider for +a moment her skill as a cutter. Her edifices consist of a multitude of +fragments belonging to three categories: oval pieces for the sides +of the cells; round pieces for the lids; and irregular pieces for the +barricades at the front and back. The last present no difficulty: the +Bee obtains them by removing from the leaf some projecting portion, +as it stands, a serrate lobe which, owing to its notches, shortens the +insect's task and lends itself better to scissor-work. So far, there +is nothing to deserve attention: it is unskilled labour, in which an +inexperienced apprentice might excel. + +With the oval pieces, it becomes another matter. What model has the +Megachile when cutting her neat ellipses out of the delicate material +for her wallets, the robinia-leaves? What mental pattern guides her +scissors? What system of measurement tells her the dimensions? One would +like to picture the insect as a living pair of compasses, capable of +tracing an elliptic curve by a certain natural inflexion of its body, +even as our arm traces a circle by swinging from the shoulder. A +blind mechanism, the mere outcome of its organization, would alone be +responsible for its geometry. This explanation would tempt me if the +large oval pieces were not accompanied by much smaller ones, also oval, +which are used to fill the empty spaces. A pair of compasses which +changes its radius of its own accord and alters the curve according to +the plan before it appears to me an instrument somewhat difficult to +believe in. There must be something better than that. The circular +pieces of the lid suggest it to us. + +If, by the mere flexion inherent in her structure, the Leaf-cutter +succeeds in cutting out ovals, how does she succeed in cutting out +rounds? Can we admit the presence of other wheels in the machinery for +the new pattern, so different in shape and size? Besides, the real point +of the difficulty does not lie there. These rounds, for the most part, +fit the mouth of the jar with almost exact precision. When the cell +is finished, the Bee flies hundreds of yards away to make the lid. She +arrives at the leaf from which the disk is to be cut. What picture, what +recollection has she of the pot to be covered? Why, none at all: she has +never seen it; she does her work underground, in utter darkness! At the +utmost, she can have the indications of touch: not actual indications, +of course, for the pot is not there, but past indications, useless in +a work of precision. And yet the disk to be cut out must have a fixed +diameter: if it were too large, it would not go in; if too small, it +would close badly, it would slip down on the honey and suffocate the +egg. How shall it be given its correct dimensions without a pattern? The +Bee does not hesitate for a moment. She cuts out her disk with the same +celerity which she would display in detaching any shapeless lobe that +might do for a stopper; and that disk, without further measurement, is +of the right size to fit the pot. Let whoso will explain this geometry, +which in my opinion is inexplicable, even when we allow for memory +begotten of touch and sight. + +One winter evening, as we were sitting round the fire, whose cheerful +blaze unloosed our tongues, I put the problem of the Leaf-cutter to my +family: + +'Among your kitchen-utensils,' I said, 'you have a pot in daily use; +but it has lost its lid, which was knocked over and broken by the Tomcat +playing among the shelves. To-morrow is market-day and one of you will +be going to Orange to buy the week's provisions. Would she undertake, +without a measure of any kind, with the sole aid of memory, which we +would allow her to refresh before starting by a careful examination of +the object, to bring back exactly what the pot wants, a lid neither too +large nor too small, in short the same size as the top?' + +It was admitted with one accord that nobody would accept such a +commission without taking a measure with her, or at least a bit of +string giving the width. Our memory for sizes is not accurate enough. +She would come back from the town with something that 'might do'; and it +would be the merest chance if this turned out to be the right size. + +Well, the Leaf-cutter is even less well-off than ourselves. She has no +mental picture of her pot, because she has never seen it; she is not +able to pick and choose in the crockery-dealer's heap, which acts as +something of a guide to our memory by comparison; she must, without +hesitation, far away from her home, cut out a disk that fits the top of +her jar. What is impossible to us is child's-play to her. Where we could +not do without a measure of some kind, a bit of string, a pattern or +a scrap of paper with figures upon it, the little Bee needs nothing at +all. In housekeeping matters she is cleverer than we are. + +One objection was raised. Was it not possible that the Bee, when at work +on the shrub, should first cut a round piece of an approximate diameter, +larger than that of the neck of the jar, and that afterwards, on +returning home, she should gnaw away the superfluous part until the lid +exactly fitted the pot? These alterations made with the model in front +of her would explain everything. + +That is perfectly true; but are there any alterations? To begin with, it +seems to me hardly possible that the insect can go back to the cutting +once the piece is detached from the leaf: it lacks the necessary support +to gnaw the flimsy disk with any precision. A tailor would spoil his +cloth if he had not the support of a table when cutting out the pieces +for a coat. The Megachile's scissors, so difficult to wield on anything +not firmly held, would do equally bad work. + +Besides, I have better evidence than this for my refusal to believe in +the existence of alterations when the Bee has the cell in front of her. +The lid is composed of a pile of disks whose number sometimes reaches +half a score. Now the bottom part of all these disks is the under +surface of the leaf, which is paler and more strongly veined; the top +part is the upper surface, which is smooth and greener. In other words, +the insect places them in the position which they occupy when gathered. +Let me explain. In order to cut out a piece, the Bee stands on the +upper surface of the leaf. The piece detached is held in the feet and +is therefore laid with its top surface against the insect's chest at the +moment of departure. There is no possibility of its being turned over on +the journey. Consequently, the piece is laid as the Bee has just picked +it, with the lower surface towards the inside of the cell and the upper +surface towards the outside. If alterations were necessary to reduce the +lid to the diameter of the pot, the disk would be bound to get turned +over: the piece, manipulated, set upright, turned round, tried this way +and that, would, when finally laid in position, have its top or bottom +surface inside just as it happened to come. But this is exactly what +does not take place. Therefore, as the order of stacking never changes, +the disks are cut, from the first clip of the scissors, with their +proper dimensions. The insect excels us in practical geometry. I look +upon the Leaf-cutter's pot and lid as an addition to the many other +marvels of instinct that cannot be explained by mechanics; I submit it +to the consideration of science; and I pass on. + +The Silky Leaf-cutter (Megachile sericans, FONSCOL.; M. Dufourii, LEP.) +makes her nests in the disused galleries of the Anthophorae. I know +her to occupy another dwelling which is more elegant and affords a more +roomy installation: I mean the old dwelling of the fat Capricorn, the +denizen of the oaks. The metamorphosis is effected in a spacious chamber +lined with soft felt. When the long-horned Beetle reaches the adult +stage, he releases himself and emerges from the tree by following a +vestibule which the larva's powerful tools have prepared beforehand. +When the deserted cabin, owing to its position, remains wholesome and +there is no sign of any running from its walls, no brown stuff smelling +of the tan-yard, it is soon visited by the Silky Megachile, who finds in +it the most sumptuous of the apartments inhabited by the Leaf-cutters. +It combines every condition of comfort: perfect safety, an even +temperature, freedom from damp, ample room; and so the mother who is +fortunate enough to become the possessor of such a lodging uses it +entirely, vestibule and drawing-room alike. Accommodation is found for +all her family of eggs; at least, I have nowhere seen nests as populous +as here. + +One of them provides me with seventeen cells, the highest number +appearing in my census of the Megachile clan. Most of them are lodged in +the nymphal chamber of the Capricorn; and, as the spacious recess is too +wide for a single row, the cells are arranged in three parallel series. +The remainder, in a single string, occupy the vestibule, which is +completed and filled up by the terminal barricade. In the materials +employed, hawthorn-and paliurus-leaves predominate. The pieces, both +in the cells and in the barrier, vary in size. It is true that the +hawthorn-leaves, with their deep indentations, do not lend themselves to +the cutting of neat oval pieces. The insect seems to have detached each +morsel without troubling overmuch about the shape of the piece, so long +as it was big enough. Nor has it been very particular about arranging +the pieces according to the nature of the leaf: after a few bits of +paliurus come bits of vine and hawthorn; and these again are followed by +bits of bramble and paliurus. The Bee has collected her pieces anyhow, +taking a bit here and there, just as her fancy dictated. Nevertheless, +paliurus is the commonest, perhaps for economical reasons. + +I notice, in fact, that the leaves of this shrub, instead of being +used piecemeal, are employed whole, when they do not exceed the proper +dimensions. Their oval form and their moderate size suit the insect's +requirements; and there is therefore no necessity to cut them into +pieces. The leaf-stalk is clipped with the scissors and, without more +ado, the Megachile retires the richer by a first-rate bit of material. + +Split up into their component parts, two cells give me altogether +eighty-three pieces of leaves, whereof eighteen are smaller than the +others and of a round shape. The last-named come from the lids. If they +average forty-two each, the seventeen cells of the nest represent seven +hundred and fourteen pieces. These are not all: the nest ends, in the +Capricorn's vestibule, with a stout barricade in which I count three +hundred and fifty pieces. The total therefore amounts to one thousand +and sixty-four. All those journeys and all that work with the scissors +to furnish the deserted chamber of the Cerambyx! If I did not know the +Leaf-cutter's solitary and jealous disposition, I should attribute the +huge structure to the collaboration of several mothers; but there is +no question of communism in this case. One dauntless creature and one +alone, one solitary, inveterate worker, has produced the whole of +the prodigious mass. If work is the best way to enjoy life, this one +certainly has not been bored during the few weeks of her existence. + +I gladly award her the most honourable of eulogies, that due to the +industrious; and I also compliment her on her talent for closing the +honey-pots. The pieces stacked into lids are round and have nothing +to suggest those of which the cells and the final barricade are made. +Excepting the first, those nearest the honey, they are perhaps cut a +little less neatly than the disks of the White-girdled Leaf-cutter; no +matter: they stop the jar perfectly, especially when there are some ten +of them one above the other. When cutting them, the Bee was as sure of +her scissors as a dressmaker guided by a pattern laid on the stuff; and +yet she was cutting without a model, without having in front of her the +mouth to be closed. To enlarge on this interesting subject would mean to +repeat oneself. All the Leaf-cutters have the same talent for making the +lids of their pots. + +A less mysterious question than this geometrical problem is that of the +materials. Does each species of Megachile keep to a single plant, or +has it a definite botanical domain wherein to exercise its liberty of +choice? The little that I have already said is enough to make us suspect +that the insect is not restricted to one plant; and this is confirmed +by an examination of the separate cells, piece by piece, when we find a +variety which we were far from imagining at first. Here is the flora +of the Megachiles in my neighbourhood, a very incomplete flora and +doubtless capable of considerable amplification by future researches. + +The Silky Leaf-cutter gathers the materials for her pots, her lids and +her barricades from the following plants: paliurus, hawthorn, vine, +wild briar, bramble, holm-oak, amelanchier, terebinthus, sage-leaved +rock-rose. The first three supply the greater part of the leaf-work; the +last three are represented only by rare fragments. + +The Hare-footed Leaf-cutter (Megachile lagopoda, LIN.) which I see very +busy in my enclosure, though she only collects her materials there, +exploits the lilac and the rose-tree by preference. From time to time, +I see her also cutting bits out of the robinia, the quince-tree and the +cherry-tree. In the open country, I have found her building with the +leaves of the vine alone. + +The Silvery Leaf-cutter (Megachile argentata, FAB.), another of my +guests, shares the taste of the aforesaid for the lilac and the rose, +but her domain includes in addition the pomegranate-tree, the bramble, +the vine, the common dogwood and the cornelian cherry. + +The White-girdled Leaf-cutter likes the robinia, to which she adds, in +lavish proportions, the vine, the rose and the hawthorn and sometimes, +in moderation, the reed and the whitish-leaved rock-rose. + +The Black-tipped Leaf-cutter (Megachile apicalis, SPIN.) has for her +abode the cells of the Mason-bee of the Pebbles and the ruined nests of +the Osmiae and Anthidia in the Snail-shells. I have not known her to use +any other materials than the wild briar and the hawthorn. + +Incomplete though it be, this list tells us that the Megachiles do not +have exclusive botanical tastes. Each species manages extremely well +with several plants differing greatly in appearance. The first condition +to be fulfilled by the shrub exploited is that it be near the +nest. Frugal of her time, the Leaf-cutter declines to go on distant +expeditions. Whenever I come upon a recent Megachile-nest, I am not long +in finding in the neighbourhood, without much searching, the tree or +shrub from which the Bee has cut her pieces. + +Another main condition is a fine and supple texture, especially for the +first disks used in the lid and for the pieces which form the lining of +the wallet. The rest, less carefully executed, allows of coarser +stuff; but even then the piece must be flexible and lend itself to the +cylindrical configuration of the tunnel. The leaves of the rock-roses, +thick and roughly fluted, fulfil this condition unsatisfactorily, for +which reason I see them occurring only at very rare intervals. The +insect has gathered pieces of them by mistake and, not finding them good +to use, has ceased to visit the unprofitable shrub. Stiffer still, the +leaf of the holm-oak in its full maturity is never employed: the Silky +Leaf-cutter uses it only in the young state and then in moderation; she +can get her velvety pieces better from the vine. In the lilac-bushes so +zealously exploited before my eyes by the Hare-footed Leaf-cutter occur +a medley of different shrubs which, from their size and the lustre of +their leaves, should apparently suit that sturdy pinker. They are the +shrubby hare's-ear, the honeysuckle, the prickly butcher's-broom, the +box. What magnificent disks ought to come from the hare's-ear and the +honeysuckle! One could get an excellent piece, without further labour, +by merely cutting the leaf-stalk of the box, as Megachile sericans does +with her paliurus. The lilac-lover disdains them absolutely. For +what reason? I fancy that she finds them too stiff. Would she think +differently if the lilac-bush were not there? Perhaps so. + +In short, apart from the questions of texture and proximity to the +nest, the Megachile's choice, it seems to me, must depend upon whether a +particular shrub is plentiful or not. This would explain the lavish use +of the vine, an object of widespread cultivation, and of the hawthorn +and the wild briar, which form part of all our hedges. As these are to +be found everywhere, the fact that the different Leaf-cutters make use +of them is no reflection upon a host of equivalents varying according to +the locality. + +If we had to believe what people tell us about the effects of heredity, +which is said to hand down from generation to generation, ever more +firmly established, the individual habits of those who come before, the +Megachiles of these parts, experienced in the local flora by the long +training of the centuries, but complete novices in the presence of +plants which their race encounters for the first time, ought to refuse +as unusual and suspicious any exotic leaves, especially when they have +at hand plenty of the leaves made familiar by hereditary custom. The +question was deserving of separate study. + +Two subjects of my observations, the Hare-footed and the Silvery +Leaf-cutter, both of them inmates of my open-air laboratory, gave me a +definite answer. Knowing the points frequented by the two Megachiles, +I planted in their work-yard, overgrown with briar and lilac, two +outlandish plants which seemed to me to fulfil the required conditions +of suppleness of texture, namely, the ailantus, a native of Japan, and +the Virginian physostegia. Events justified the selection: both Bees +exploited the foreign flora with the same assiduity as the local +flora, passing from the lilac to the ailantus, from the briar to the +physostegia, leaving the one, going back to the other, without drawing +distinctions between the known and the unknown. Inveterate habit could +not have given greater certainty, greater ease to their scissors, though +this was their first experience of such a material. + +The Silvery Leaf-cutter lent herself to an even more conclusive test. As +she readily makes her nest in the reeds of my apparatus, I was able, +up to a certain point, to create a landscape for her and select its +vegetation myself. I therefore moved the reed-hive to a part of the +enclosure stocked chiefly with rosemary, whose scanty foliage is not +adapted for the Bee's work, and near the apparatus I arranged an exotic +shrubbery in pots, including notably the smooth lopezia, from Mexico, +and the long-fruited capsicum, an Indian annual. Finding close at hand +the wherewithal to build her nest, the Leaf-cutter went no further +afield. The lopezia suited her especially, so much so that almost the +whole nest was composed of it. The rest had been gathered from the +capsicum. + +Another recruit, whose co-operation I had in no way engineered, came +spontaneously to offer me her evidence. This was the Feeble Leaf-cutter +(Megachile imbecilla, GERST.). Nearly a quarter of a century ago, I saw +her, all through the month of July, cutting out her rounds and ellipses +at the expense of the petals of the Pelargonium zonale, the common +geranium. Her perseverance devastated--there is no other word for +it--my modest array of pots. Hardly was a blossom out, when the +ardent Megachiles came and scalloped it into crescents. The colour was +indifferent to her: red, white or pink, all the petals underwent +the disastrous operation. A few captures, ancient relics of my +collecting-boxes by this time, indemnified me for the pillage. I have +not seen this unpleasant Bee since. With what does she build when there +are no geranium-flowers handy? I do not know; but the fact remains that +the fragile tailoress used to attack the foreign flower, a fairly +recent acquisition from the Cape, as though all her race had never done +anything else. + +These details leave us with one obvious conclusion, which is contrary to +our original ideas, based on the unvarying character of insect industry. +In constructing their jars, the Leaf-cutters, each following the taste +peculiar to her species, do not make use of this or that plant to +the exclusion of the others; they have no definite flora, no domain +faithfully transmitted by heredity. Their pieces of leaves vary +according to the surrounding vegetation; they vary in different layers +of the same cell. Everything suits them, exotic or native, rare or +common, provided that the bit cut out be easy to employ. It is not the +general aspect of the shrub, with its fragile or bushy branches, its +large or small, green or grey, dull or glossy leaves, that guides +the insect: such advanced botanical knowledge does not enter into the +question at all. In the thicket chosen as a pinking-establishment, the +Megachile sees but one thing: leaves useful for her work. The Shrike, +with his passion for plants with long, woolly sprigs, knows where +to find nicely-wadded substitutes when his favourite growth, the +cotton-rose, is lacking; the Megachile has much wider resources: +indifferent to the plant itself, she looks only into the foliage. If she +finds leaves of the proper size, of a dry texture capable of defying the +damp and of a suppleness favourable to cylindrical curving, that is +all she asks; and the rest does not matter. She has therefore an almost +unlimited field for her labour. + +These sudden and wholly unprovoked changes give cause for reflection. +When my geranium-flowers were devastated, how had the obtrusive Bee, +untroubled by the profound dissimilarity between the petals, snow-white +here, bright scarlet there, how had she learnt her trade? Nothing tells +us that she herself was not for the first time exploiting the plant from +the Cape; and, if she really did have predecessors, the habit had not +had time to become inveterate, considering the modern importation of the +geranium. Where again did the Silvery Megachile, for whom I created an +exotic shrubbery, make the acquaintance of the lopezia, which comes from +Mexico? She certainly is making a first start. Never did her village or +mine possess a stalk of that chilly denizen of our hot-houses. She is +making a first start; and behold her straightway a graduate, versed in +the art of carving unfamiliar foliage. + +People often talk of the long apprenticeships served by instinct, of its +gradual acquirements, of its talents, the laborious work of the ages. +The Megachiles affirm the exact opposite. They tell me that the animal, +though invariable in the essence of its art, is capable of innovation +in the details; but at the same time they assure me that any such +innovation is sudden and not gradual. Nothing prepares the innovations, +nothing improves them or hands them down; otherwise a selection would +long ago have been made amid the diversity of foliage; and the +shrub recognized as the most serviceable, especially when it is also +plentiful, would alone supply all the building-materials needed. If +heredity transmitted industrial discoveries, a Megachile who thought of +cutting her disks out of pomegranate-leaves and found them satisfactory +ought to have instilled a liking for similar materials into her +descendants; and we should this day find Leaf-cutters faithful to the +pomegranate-leaves, workers who remained exclusive in their choice of +the raw material. The facts refute these theories. + +People also say: + +'Grant us a variation, however small, in the insect's industry; and +that variation, accentuated more and more, will produce a new race and +finally a fixed species.' + +This trifling variation is the fulcrum for which Archimedes clamoured in +order to lift the world with his system of levers. The Megachiles +offer us one and a very great one: the indefinite variation of their +materials. What will the theorists' levers lift with this fulcrum? Why, +nothing at all! Whether they cut the delicate petals of the geranium or +the tough leaves of the lilac-bushes, the Leaf-cutters are and will +be what they were. This is what we learn from the persistence of each +species in its structural details, despite the great variety of the +foliage employed. + + + + +CHAPTER 9. THE COTTON-BEES. + +The evidence of the Leaf-cutters proves that a certain latitude is +left to the insect in its choice of materials for the nest; and this is +confirmed by the testimony of the Anthidia, the cotton-manufacturers. +My district possesses five: A. Florentinum, LATR., A. diadema, LATR., A. +manicatum, LATR., A. cingulatum, LATR., A. scapulare, LATR. None of them +creates the refuge in which the cotton goods are manufactured. Like the +Osmiae and the Leaf-cutters, they are homeless vagrants, adopting, +each to her own taste, such shelter as the work of others affords. The +Scapular Anthidium is loyal to the dry bramble, deprived of its pith and +turned into a hollow tube by the industry of various mining Bees, among +which figure, in the front rank, the Ceratinae, dwarf rivals of the +Xylocopa, or Carpenter-bee, that mighty driller of rotten wood. +The spacious galleries of the Masked Anthophora suit the Florentine +Anthidium, the foremost member of the genus so far as size is concerned. +The Diadem Anthidium considers that she has done very well if she +inherits the vestibule of the Hairy-footed Anthophora, or even the +ordinary burrow of the Earth-worm. Failing anything better, she may +establish herself in the dilapidated dome of the Mason-bee of the +Pebbles. The Manicate Anthidium shares her tastes. I have surprised the +Girdled Anthidium cohabiting with a Bembex-wasp. The two occupants of +the cave dug in the sand, the owner and the stranger, were living in +peace, both intent upon their business. Her usual habitation is some +hole or other in the crevices of a ruined wall. To these refuges, the +work of others, we can add the stumps of reeds, which are as popular +with the various cotton-gatherers as with the Osmiae; and, after we have +mentioned a few most unexpected retreats, such as the sheath provided +by a hollow brick or the labyrinth furnished by the lock of a gate, we +shall have almost exhausted the list of domiciles. + +Like the Osmiae and the Leaf-cutters, the Anthidium shows an urgent need +of a ready-made home. She never houses herself at her own expense. Can +we discover the reason? Let us first consult a few hard workers who are +artificers of their own dwellings. The Anthophora digs corridors and +cells in the road-side banks hardened by the sun; she does not erect, +she excavates; she does not build, she clears. Toiling away with her +mandibles, atom by atom, she manages to contrive the passages and +chambers necessary for her eggs; and a huge business it is. She has, in +addition, to polish and glaze the rough sides of her tunnels. What would +happen if, after obtaining a home by dint of long-continued toil, +she had next to line it with wadding, to gather the fibrous down from +cottony plants and to felt it into bags suitable for the honey-paste? +The hard-working Bee would not be equal to producing all these +refinements. Her mining calls for too great an expenditure of time and +strength to leave her the leisure for luxurious furnishing. Chambers and +corridors, therefore, will remain bare. + +The Carpenter-bee gives us the same answer. When with her joiner's +wimble she has patiently bored the beam to a depth of nine inches, would +she be able to cut out and place in position the thousand and one pieces +which the Silky Leaf-cutter employs for her nest? Time would fail her, +even as it would fail a Megachile who, lacking the Capricorn's chamber, +had herself to dig a home in the trunk of the oak. Therefore the +Carpenter-bee, after the tedious work of boring, gets the installation +done in the most summary fashion, simply running up a sawdust partition. + +The two things, the laborious business of obtaining a lodging and the +artistic work of furnishing, seem unable to go together. With the +insect as with man, he who builds the house does not furnish it, he who +furnishes it does not build it. To each his share, because of lack of +time. Division of labour, the mother of the arts, makes the workman +excel in his department; one man for the whole work would mean +stagnation, the worker never getting beyond his first crude attempts. +Animal industry is a little like our own: it does not attain its +perfection save with the aid of obscure toilers, who, without knowing +it, prepare the final masterpiece. I see no other reason for this +need of a gratuitous lodging for the Megachile's leafy basket or the +Anthidia's cotton purses. In the case of other artists who handle +delicate things that require protection, I do not hesitate to assume +the existence of a ready-made home. Thus Reaumur tells us of the +Upholsterer-bee, Anthocopa papaveris, who fashions her cells with +poppy-petals. I do not know the flower-cutter, I have never seen her; +but her art tells me plainly enough that she must establish herself in +some gallery wrought by others, as, for instance, in an Earth-worm's +burrow. + +We have but to see the nest of a Cotton-bee to convince ourselves that +its builder cannot at the same time be an indefatigable navvy. When and +newly-felted and not yet made sticky with honey, the wadded purse is +by far the most elegant known specimen of entomological nest-building, +especially where the cotton is of a brilliant white, as is frequently +the case in the manufacturers of the Girdled Anthidium. No bird's-nest, +however deserving of our admiration, can vie in fineness of flock, in +gracefulness of form, in delicacy of felting with this wonderful bag, +which our fingers, even with the aid of tools, could hardly imitate, for +all their dexterity. I abandon the attempt to understand how, with its +little bales of cotton brought up one by one, the insect, no otherwise +gifted than the kneaders of mud and the makers of leafy baskets, manages +to felt what it has collected into a homogeneous whole and then to work +the product into a thimble-shaped wallet. Its tools as a master-fuller +are its legs and its mandibles, which are just like those possessed by +the mortar-kneaders and Leaf-cutters; and yet, despite this similarity +of outfit, what a vast difference in the results obtained! + +To see the Cotton-bees' talents in action seems an undertaking fraught +with innumerable difficulties: things happen at a depth inaccessible to +the eye; and to persuade the insect to work in the open does not lie +in our power. One resource remained and I did not fail to turn to +it, though hitherto I have been wholly unsuccessful. Three species, +Anthidium diadema, A. manicatum and A. florentinum--the first-named in +particular--show themselves quite ready to take up their abode in my +reed-apparatus. All that I had to do was to replace the reeds by glass +tubes, which would allow me to watch the work without disturbing the +insect. This stratagem had answered perfectly with the Three-horned +Osmia and Latreille's Osmia, whose little housekeeping-secrets I had +learnt thanks to the transparent dwelling-house. Why should it not +answer for its Cotton-bees and, in the same way, with the Leaf-cutters? +I almost counted on success. Events betrayed my confidence. For +four years I supplied my hives with glass tubes and not once did the +Cotton-weavers or the Leaf-cutters condescend to take up their quarters +in the crystal palaces. They always preferred the hovel provided by the +reed. Shall I persuade them one day? I do not abandon all hope. + +Meanwhile, let me describe the little that I saw. More or less stocked +with cells, the reed is at last closed, right at the orifice, with +a thick plug of cotton, usually coarser than the wadding of the +honey-satchels. It is the equivalent of the Three-horned Osmia's +barricade of mud, of the leaf-putty of Latreille's Osmia, of the +Megachiles' barrier of leaves cut into disks. All these free tenants are +careful to shut tight the door of the dwelling, of which they have often +utilized only a portion. To watch the building of this barricade, which +is almost external work, demands but a little patience in waiting for +the favourable moment. + +The Anthidium arrives at last, carrying the bale of cotton for the +plugging. With her fore-legs she tears it apart and spreads it out; with +her mandibles, which go in closed and come out open, she loosens the +hard lumps of flock; with her forehead she presses each new layer upon +the one below. And that is all. The insect flies off, returns the richer +by another bale and repeats the performance until the cotton barrier +reaches the level of the opening. We have here, remember, a rough task, +in no way to be compared with the delicate manufacturer of the bags; +nevertheless, it may perhaps tell us something of the general procedure +of the finer work. The legs do the carding, the mandibles the dividing, +the forehead the pressing; and the play of these implements produces the +wonderful cushioned wallet. That is the mechanism in the lump; but what +of the artistry? + +Let us leave the unknown for facts within the scope of observation. I +will question the Diadem Anthidium in particular, a frequent inmate +of my reeds. I open a reed-stump about two decimetres long by twelve +millimetres in diameter. (About seven and three-quarter inches by +half an inch.--Translator's Note.) The end is occupied by a column of +cotton-wool comprising ten cells, without any demarcation between +them on the outside, so that their whole forms a continuous cylinder. +Moreover, thanks to a close felting, the different compartments are +soldered together, so much so that, when pulled by the end, the cotton +edifice does not break into sections, but comes out all in one piece. +One would take it for a single cylinder, whereas in reality the work +is composed of a series of chambers, each of which has been constructed +separately, independently of the one before, except perhaps at the base. + +For this reason, short of ripping up the soft dwelling, still full of +honey, it is impossible to ascertain the number of storeys; we must +wait until the cocoons are woven. Then our fingers can tell the cells by +counting the knots that resist pressure under the cover of wadding. This +general structure is easily explained. A cotton bag is made, with the +sheath of the reed as a mould. If this guiding sheath were lacking, the +thimble shape would be obtained all the same, with no less elegance, +as is proved by the Girdled Anthidium, who makes her nest in some +hiding-place or other in the walls or the ground. When the purse is +finished, the provisions come and the egg, followed by the closing of +the cell. We do not here find the geometrical lid of the Leaf-cutters, +the pile of disks tight-set in the mouth of the jar. The bag is closed +with a cotton sheet whose edges are soldered by a felting-process to the +edges of the opening. The soldering is so well done that the honey-pouch +and its cover form an indivisible whole. Immediately above it, the +second cell is constructed, having its own base. At the beginning of +this work, the insect takes care to join the two storeys by felting the +ceiling of the first to the floor of the second. Thus continued to the +end, the work, with its inner solderings, becomes an unbroken cylinder, +in which the beauties of the separate wallets disappear from view. In +very much the same fashion, but with less adhesion among the different +cells, do the Leaf-cutters act when stacking their jars in a column +without any external division into storeys. + +Let us return to the reed-stump which gives us these details. Beyond the +cotton-wool cylinder wherein ten cocoons are lodged in a row comes +an empty space of half a decimetre or more. (About two +inches.--Translator's Note.) The Osmiae and the Leaf-cutters are also +accustomed to leave these long, deserted vestibules. The nest ends, at +the orifice of the reed, with a strong plug of flock coarser and less +white than that of the cells. This use of closing-materials which are +less delicate in texture but of greater resisting-power, while not an +invariable characteristic, occurs frequently enough to make us suspect +that the insect knows how to distinguish what is best suited now to the +snug sleeping-berth of the larvae, anon to the defensive barricade of +the home. Sometimes the choice is an exceedingly judicious one, as is +shown by the nest of the Diadem Anthidium. Time after time, whereas the +cells were composed of the finest grade of white cotton, gathered from +Centaurea solsticialis, or St. Barnaby's thistle, the barrier at the +entrance, differing from the rest of the work in its yellow colouring, +was a heap of close-set bristles supplied by the scallop-leaved mullein. +The two functions of the wadding are here plainly marked. The delicate +skin of the larvae needs a well-padded cradle; and the mother collects +the softest materials that the cottony plants provide. Rivalling the +bird, which furnishes the inside of the nest with wool and strengthens +the outside with sticks, she reserves for the grubs' mattress the finest +down, so hard to find and collected with such patience. But, when it +becomes a matter of shutting the door against the foe, then the entrance +bristles with forbidding caltrops, with stiff, prickly hairs. + +This ingenious system of defence is not the only one known to the +Anthidia. More distrustful still, the Manicate Anthidium leaves no space +in the front part of the reed. Immediately after the column of cells, +she heaps up, in the uninhabited vestibule, a conglomeration of rubbish, +whatever chance may offer in the neighbourhood of the nest: little +pieces of gravel, bits of earth, grains of sawdust, particles of mortar, +cypress-catkins, broken leaves, dry Snail-droppings and any other +material that comes her way. The pile, a real barricade this time, +blocks the reed completely to the end, except about two centimetres +(About three-quarters of an inch.--Translator's Note.) left for the +final cotton plug. Certainly no foe will break in through the double +rampart; but he will make an insidious attack from the rear. +The Leucopsis will come and, with her long probe, thanks to some +imperceptible fissure in the tube, will insert her dread eggs and +destroy every single inhabitant of the fortress. Thus are the Manicate +Anthidium's anxious precautions outwitted. + +If we had not already seen the same thing with the Leaf-cutters, this +would be the place to enlarge upon the useless tasks undertaken by the +insect when, with its ovaries apparently depleted, it goes on spending +its strength with no maternal object in view and for the sole pleasure +of work. I have come across several reeds stopped up with flock though +containing nothing at all, or else furnished with one, two or three +cells devoid of provisions or eggs. The ever-imperious instinct +for gathering cotton and felting it into purses and heaping it into +barricades persists, fruitlessly, until life fails. The Lizard's tail +wriggles, curls and uncurls after it is detached from the animal's body. +In these reflex movements, I seem to see not an explanation, certainly, +but a rough image of the industrious persistency of the insect, still +toiling away at its business, even when there is nothing useful left to +do. This worker knows no rest but death. + +I have said enough about the dwelling of the Diadem Anthidium; let us +look at the inhabitant and her provisions. The honey is pale-yellow, +homogeneous and of a semifluid consistency, which prevents it from +trickling through the porous cotton bag. The egg floats on the surface +of the heap, with the end containing the head dipped into the paste. To +follow the larva through its progressive stages is not without interest, +especially on account of the cocoon, which is one of the most singular +that I know. With this object in view, I prepare a few cells that lend +themselves to observation. I take a pair of scissors, slice a piece off +the side of the cotton-wool purse, so as to lay bare both the victuals +and the consumer, and place the ripped cell in a short glass tube. +During the first few days, nothing striking happens. The little grub, +with its head still plunged in the honey, slakes its thirst with long +draughts and waxes fat. A moment comes...But let us go back a little +farther, before broaching this question of sanitation. + +Every grub, of whatever kind, fed on provisions collected by the mother +and placed in a narrow cell is subject to conditions of health unknown +to the roving grub that goes where it likes and feeds itself on what it +can pick up. The first, the recluse, is no more able than the second, +the gadabout, to solve the problem of a food which can be entirely +assimilated, without leaving an unclean residue. The second gives no +thought to these sordid matters: any place suits it for getting rid +of that difficulty. But what will the other do with its waste matter, +cooped up as it is in a tiny cell stuffed full of provisions? A most +unpleasant mixture seems inevitable. Picture the honey-eating grub +floating on liquid provisions and fouling them at intervals with its +excretions! The least movement of the hinder-part would cause the +whole to amalgamate; and what a broth that would make for the delicate +nursling! No, it cannot be; those dainty epicures must have some method +of escaping these horrors. + +They all have, in fact, and most original methods at that. Some take +the bull by the horns, so to speak, and, in order not to soil things, +refrain from uncleanliness until the end of the meal: they keep the +dropping-trap closed as long as the victuals are unfinished. This is +a radical scheme, but not in every one's power, it appears. It is +the course adopted, for instance, by the Sphex-wasps and the +Anthophora-bees, who, when the whole of the food is consumed, expel at +one shot the residues amassed in the intestines since the commencement +of the repast. + +Others, the Osmiae in particular, accept a compromise and begin to +relieve the digestive tract when a suitable space has been made in +the cell through the gradual disappearance of the victuals. Others +again--more hurried these--find means of obeying the common law pretty +early by engaging in stercoral manufactures. By a stroke of genius, they +make the unpleasant obstruction into building-bricks. We already know +the art of the Lily-beetle (Crioceris merdigera. Fabre's essay on this +insect has not yet been translated into English; but readers interested +in the matter will find a full description in "An Introduction to +Entomology," by William Kirby, Rector of Barham, and William Spence: +letter 21.--Translator's Note.), who, with her soft excrement, makes +herself a coat wherein to keep cool in spite of the sun. It is a very +crude and revolting art, disgusting to the eye. The Diadem Anthidium +belongs to another school. With her droppings she fashions masterpieces +of marquetry and mosaic, which wholly conceal their base origin from the +onlooker. Let us watch her labours through the windows of my tubes. + +When the portion of food is nearly half consumed, there begins and goes +on to the end a frequent defecation of yellowish droppings, each hardly +the size of a pin's head. As these are ejected, the grub pushes them +back to the circumference of the cell with a movement of its hinder-part +and keeps them there by means of a few threads of silk. The work of +the spinnerets, therefore, which is deferred in the others until the +provisions are finished, starts earlier here and alternates with the +feeding. In this way, the excretions are kept at a distance, away from +the honey and without any danger of getting mixed with it. They end by +becoming so numerous as to form an almost continuous screen around the +larva. This excremental awning, made half of silk and half of droppings, +is the rough draft of the cocoon, or rather a sort of scaffolding on +which the stones are deposited until they are definitely placed in +position. Pending the piecing together of the mosaic, the scaffolding +keeps the victuals free from all contamination. + +To get rid of what cannot be flung outside, by hanging it on the +ceiling, is not bad to begin with; but to use it for making a work of +art is better still. The honey has disappeared. Now commences the final +weaving of the cocoon. The grub surrounds itself with a wall of silk, +first pure white, then tinted reddish-brown by means of an adhesive +varnish. Through its loose-meshed stuff, it seizes one by one the +droppings hanging from the scaffold and inlays them firmly in the +tissue. The same mode of work is employed by the Bembex-, Stizus-and +Tachytes-wasps and other inlayers, who strengthen the inadequate woof +of their cocoons with grains of sand; only, in their cotton-wool purses, +the Anthidium's grubs substitute for the mineral particles the only +solid materials at their disposal. For them, excrement takes the place +of pebbles. + +And the work goes none the worse for it. On the contrary: when the +cocoon is finished, any one who had not witnessed the process of +manufacture would be greatly puzzled to state the nature of the +workmanship. The colouring and the elegant regularity of the outer +wrapper of the cocoon suggest some kind of basket-work made with tiny +bits of bamboo, or a marquetry of exotic granules. I too let myself be +caught by it in my early days and wondered in vain what the hermit of +the cotton wallet had used to inlay her nymphal dwelling so prettily +withal. To-day, when the secret is known to me, I admire the ingenuity +of the insect capable of obtaining the useful and the beautiful out of +the basest materials. + +The cocoon has another surprise in store for us. The end containing the +head finishes with a short conical nipple, an apex, pierced by a narrow +shaft that establishes a communication between the inside and the +out. This architectural feature is common to all the Anthidia, to the +resin-workers who will occupy our attention presently, as well as to the +cotton-workers. It is found nowhere outside the Anthidium group. + +What is the use of this point which the larva leaves bare instead of +inlaying it like the rest of the shell? What is the use of that hole, +left quite open or, at most, closed at the bottom with a feeble grating +of silk? The insect appears to attach great importance to it, from what +I see. In point of fact, I watch the careful work of the apex. The grub, +whose movements the hole enables me to follow, patiently perfects the +lower end of the conical channel, polishes it and gives it an exactly +circular shape; from time to time, it inserts into the passage its +two closed mandibles, whose points project a little way outside; then, +opening them to a definite radius, like a pair of compasses, it widens +the aperture and makes it regular. + +I imagine, without venturing, however, to make a categorical statement, +that the perforated apex is a chimney to admit the air required for +breathing. Every pupa breathes in its shell, however compact this may +be, even as the unhatched bird breathes inside the egg. The thousands +of pores with which the shell is pierced allow the inside moisture to +evaporate and the outer air to penetrate as and when needed. The stony +caskets of the Bembex- and Stizus-wasps are endowed, notwithstanding +their hardness, with similar means of exchange between the vitiated and +the pure atmosphere. Can the shells of the Anthidia be air-proof, owing +to some modification that escapes me? In any case, this impermeability +cannot be attributed to the excremental mosaic, which the cocoons of the +resin-working Anthidia do not possess, though endowed with an apex of +the very best. + +Shall we find an answer to the question in the varnish with which the +silken fabric is impregnated? I hesitate to say yes and I hesitate to +say no, for a host of cocoons are coated with a similar lacquer though +deprived of communication with the outside air. All said, without being +able at present to account for its necessity, I admit that the apex of +the Anthidia is a breathing-aperture. I bequeath to the future the task +of telling us for what reasons the collectors of both cotton and resin +leave a large pore in their shells, whereas all the other weavers close +theirs completely. + +After these biological curiosities, it remains for me to discuss the +principal subject of this chapter: the botanical origin of the materials +of the nest. By watching the insect when busy at its harvesting, or else +by examining its manufactured flock under the microscope, I was able to +learn, not without a great expenditure of time and patience, that the +different Anthidia of my neighbourhood have recourse without distinction +to any cottony plant. Most of the wadding is supplied by the Compositae, +particularly the following: Centaurea solsticialis, or St. Barnaby's +thistle; C. paniculata, or panicled centaury; Echinops ritro, or +small globe-thistle; Onopordon illyricum, or Illyrian cotton-thistle; +Helichrysum staechas, or wild everlasting; Filago germanica, or common +cotton-rose. Next come the Labiatae: Marrubium vulgare, or common white +horehound; Ballota fetida, or stinking horehound; Calamintha nepeta, +or lesser calamint; Salvia aethiopis, or woolly sage. Lastly, the +Solanaceae: Verbascum thapsus, or shepherd's club; V. sinuatum, or +scollop-leaved mullein. + +The Cotton-bees' flora, we see, incomplete as it is in my notes, +embraces plants of very different aspect. There is no resemblance in +appearance between the proud candelabrum of the cotton-thistle, with its +red tufts, and the humble stalk of the globe-thistle, with its sky-blue +capitula; between the plentiful leaves of the mullein and the scanty +foliage of the St. Barnaby's thistle; between the rich silvery fleece +of the woolly sage and the short hairs of the everlasting. With the +Anthidium, these clumsy botanical characteristics do not count; one +thing alone guides her: the presence of cotton. Provided that the plant +be more or less well-covered with soft wadding, the rest is immaterial +to her. + +Another condition, however, has to be fulfilled, apart from the fineness +of the cotton-wool. The plant, to be worth shearing, must be dead and +dry. I have never seen the harvesting done on fresh plants. In this +way, the Bee avoids mildew, which would make its appearance in a mass of +hairs still filled with sap. + +Faithful to the plant recognized as yielding good results, the Anthidium +arrives and resumes her gleaning on the edges of the parts denuded by +earlier harvests. Her mandibles scrape away and pass the tiny fluffs, +one by one, to the hind-legs, which hold the pellet pressed against the +chest, mix with it the rapidly-increasing store of down and make the +whole into a little ball. When this is the size of a pea, it goes back +into the mandibles; and the insect flies off, with its bale of cotton +in its mouth. If we have the patience to wait, we shall see it return to +the same point, at intervals of a few minutes, so long as the bag is not +made. The foraging for provisions will suspend the collecting of cotton; +then, next day or the day after, the scraping will be resumed on the +same stalk, on the same leaf, if the fleece be not exhausted. The owner +of a rich crop appears to keep to it until the closing-plug calls for +coarser materials; and even then this plug is often manufactured with +the same fine flock as the cells. + +After ascertaining the diversity of cotton-fields among our native +plants, I naturally had to enquire whether the Cotton-bee would also +put up with exotic plants, unknown to her race; whether the insect would +show any hesitation in the presence of woolly plants offered for the +first time to the rakes of her mandibles. The common clary and the +Babylonian centaury, with which I have stocked the harmas, shall be the +harvest-fields; the reaper shall be the Diadem Anthidium, the inmate of +my reeds. + +The common clary, or toute-bonne, forms part, I know, of our French +flora to-day; but it is an acclimatized foreigner. They say that a +gallant crusader, returning from Palestine with his share of glory and +bruises, brought back the toute-bonne from the Levant to help him cure +his rheumatism and dress his wounds. From the lordly manor, the plant +propagated itself in all directions, while remaining faithful to the +walls under whose shelter the noble dames of yore used to grow it for +their unguents. To this day, feudal ruins are its favourite resorts. +Crusaders and manors disappeared; the plant remained. In this case, the +origin of the clary, whether historical or legendary, is of secondary +importance. Even if it were of spontaneous growth in certain parts +of France, the toute-bonne is undoubtedly a stranger in the Vaucluse +district. Only once in the course of my long botanizing-expeditions +across the department have I come upon this plant. It was at Caromb, in +some ruins, nearly thirty years ago. I took a cutting of it; and since +then the crusaders' sage has accompanied me on all my peregrinations. +My present hermitage possesses several tufts of it: but, outside the +enclosure, except at the foot of the walls, it would be impossible to +find one. We have, therefore, a plant that is new to the country for +many miles around, a cotton-field which the Serignan Cotton-bees had +never utilized before I came and sowed it. + +Nor had they ever made use of the Babylonian centaury, which I was the +first to introduce in order to cover my ungrateful stony soil with +some little vegetation. They had never seen anything like the colossal +centaury imported from the region of the Euphrates. Nothing in the local +flora, not even the cotton-thistle, had prepared them for this stalk +as thick as a child's wrist, crowned at a height of nine feet with a +multitude of yellow balls, nor for those great leaves spreading over the +ground in an enormous rosette. What will they do in the presence of such +a find? They will take possession of it with no more hesitation than if +it were the humble St. Barnaby's thistle, the usual purveyor. + +In fact, I place a few stalks of clary and Babylonian centaury, +duly dried, near the reed-hives. The Diadem Anthidium is not long in +discovering the rich harvest. Straight away the wool is recognized as +being of excellent quality, so much so that, during the three or four +weeks of nest-building, I can daily witness the gleaning, now on the +clary, now on the centaury. Nevertheless the Babylonian plant appears to +be preferred, no doubt because of its whiter, finer and more plentiful +down. I keep a watchful eye on the scraping of the mandibles and the +work of the legs as they prepare the pellet; and I see nothing +that differs from the operations of the insect when gleaning on +the globe-thistle and the St. Barnaby's thistle. The plant from the +Euphrates and the plant from Palestine are treated like those of the +district. + +Thus we find what the Leaf-cutters taught us proved, in another way, +by the cotton-gatherers. In the local flora, the insect has no precise +domain; it reaps its harvest readily now from one species, now from +another, provided that it find the materials for its manufactures. The +exotic plant is accepted quite as easily as that of indigenous growth. +Lastly, the change from one plant to another, from the common to the +rare, from the habitual to the exceptional, from the known to the +unknown, is made suddenly, without gradual initiations. There is no +novitiate, no training by habit in the choice of the materials for +the nest. The insect's industry, variable in its details by sudden, +individual and non-transmissible innovations, gives the lie to the two +great factors of evolution: time and heredity. + + + + +CHAPTER 10. THE RESIN-BEES. + +At the time when Fabricius (Johann Christian Fabricius (1745-1808), +a noted Danish entomologist, author of "Systema entomologiae" +(1775).--Translator's Note.) gave the genus Anthidium its name, a name +still used in our classifications, entomologists troubled very little +about the live animal; they worked on corpses, a dissecting-room method +which does not yet seem to be drawing to an end. They would examine +with a conscientious eye the antenna, the mandible, the wing, the leg, +without asking themselves what use the insect had made of those organs +in the exercise of its calling. The animal was classified very nearly +after the manner adopted in crystallography. Structure was everything; +life, with its highest prerogatives, intellect, instinct, did not count, +was not worthy of admission into the zoological scheme. + +It is true that an almost exclusively necrological study is obligatory +at first. To fill one's boxes with insects stuck on pins is an operation +within the reach of all; to watch those same insects in their mode of +life, their work, their habits and customs is quite a different +thing. The nomenclator who lacks the time--and sometimes also the +inclination--takes his magnifying-glass, analyzes the dead body +and names the worker without knowing its work. Hence the number of +appellations the least of whose faults is that they are unpleasant to +the ear, certain of them, indeed, being gross misnomers. Have we not, +for instance, seen the name of Lithurgus, or stone-worker, given to a +Bee who works in wood and nothing but wood? Such absurdities will be +inevitable until the animal's profession is sufficiently familiar to +lend its aid in the compiling of diagnoses. I trust that the future will +see this magnificent advance in entomological science: men will reflect +that the impaled specimens in our collections once lived and followed +a trade; and anatomy will be kept in its proper place and made to leave +due room for biology. + +Fabricius did not commit himself with his expression Anthidium, which +alludes to the love of flowers, but neither did he mention anything +characteristic: as all Bees have the same passion in a very high degree, +I see no reason to treat the Anthidia as more zealous looters than the +others. If he had known their cotton nests, perhaps the Scandinavian +naturalist would have given them a more logical denomination. As for me, +in a language wherein technical parade is out of place, I will call them +the Cotton-bees. + +The term requires some limiting. To judge by my finds, in fact, the old +genus Anthidium, that of the classifying entomologists, comprises in my +district two very different corporations. One is known to us and works +exclusively in wadding; the other, which we are about to study, works in +resin, without ever having recourse to cotton. Faithful to my extremely +simple principle of defining the worker, as far as possible, by his +work, I will call the members of this guild the Resin-bees. Thus +confining myself to the data supplied by my observations, I divide the +Anthidium group into equal sections, of equal importance, for which I +demand special generic titles; for it is highly illogical to call the +carders of wool and the kneaders of resin by the same name. I surrender +to those whom it concerns the honour of effecting this reform in the +orthodox fashion. + +Good luck, the friend of the persevering, made me acquainted in +different parts of Vaucluse with four Resin-bees whose singular trade +no one had yet suspected. To-day, I find them all four again in my own +neighbourhood. They are the following: Anthidium septemdentatum, LATR., +A. bellicosum, LEP., A. quadrilobum, LEP., and A. Latreillii, LEP. +The first two make their nests in deserted Snail-shells; the other two +shelter their groups of cells sometimes in the ground, sometimes under a +large stone. We will first discuss the inhabitants of the Snail-shell. +I made a brief reference to them in an earlier chapter, when speaking of +the distribution of the sexes. This mere allusion, suggested by a study +of a different kind, must now be amplified. I return to it with fuller +particulars. + +The stone-heaps in the Roman quarries near Serignan, which I have so +often visited in search of the nests of the Osmia who takes up her abode +in Snail-shells, supply me also with the two Resin-bees installed +in similar quarters. When the Field-mouse has left behind him a rich +collection of empty shells scattered all round his hay mattress under +the slab, there is always a hope of finding some Snail-shells plugged +with mud and, here and there, mixed with them, a few Snail-shells closed +with resin. The two Bees work next door to each other, one using clay, +the other gum. The excellence of the locality is responsible for this +frequent cohabitation, shelter being provided by the broken stone from +the quarry and lodgings by the shells which the Mouse has left behind. + +At places where dead Snail-shells are few and far between, as in the +crevices of rustic walls, each Bee occupies by herself the shells which +she has found. But here, in the quarries, our crop will certainly be +a double or even a treble one, for both Resin-bees frequent the same +heaps. Let us, therefore, lift the stones and dig into the mound until +the excessive dampness of the subsoil tells us that it is useless to +look lower down. Sometimes at the moment of removing the first layer, +sometimes at a depth of eighteen inches, we shall find the Osmia's +Snail-shell and, much more rarely, the Resin-bee's. Above all, patience! +The job is none of the most fruitful; nor is it exactly an agreeable +one. By dint of turning over uncommonly jagged stones, our fingertips +get hurt, lose their skin and become as smooth as though we had held +them on a grindstone. After a whole afternoon of this work, our back +will be aching, our fingers will be itching and smarting and we shall +possess a dozen Osmia-nests and perhaps two or three Resin-bees' nests. +Let us be content with that. + +The Osmia's shells can be recognized at once, as being closed at +the orifice with a clay cover. The Anthidium's call for a special +examination, without which we should run a great risk of filling our +pockets with cumbersome rubbish. We find a dead Snail-shell among the +stones. Is it inhabited by the Resin-bee or not? The outside tells us +nothing. The Anthidium's work comes at the bottom of the spiral, a long +way from the mouth; and, though this is wide open, the eye cannot travel +far enough along the winding stair. I hold up the doubtful shell to the +light. If it is completely transparent, I know that it is empty and I +put it back to serve for future nests. If the second whorl is opaque, +the spiral contains something. What does it contain? Earth washed in by +the rain? Remnants of the putrefied Snail? That remains to be seen. +With a little pocket-trowel, the inquisitorial implement which always +accompanies me, I make a wide window in the middle of the final whorl. +If I see a gleaming resin floor, with incrustations of gravel, the +thing is settled: I possess an Anthidium's nest. But, oh the number of +failures that go to one success! The number of windows vainly opened in +shells whose bottom is stuffed with clay or with noisome corpses! Thus +picking shells among the overturned stone-heaps, inspecting them in +the sun, breaking into them with the trowel and nearly always rejecting +them, I manage, after repeated attempts, to obtain my materials for this +chapter. + +The first to hatch is the Seven-pronged Resin-bee (Anthidium +septemdentatum). We see her, in the month of April, lumbering along to +the rubbish-heaps in the quarries and the low boundary-walls, in search +of her Snail-shell. She is a contemporary of the Three-horned Osmia, who +begins operations in the last week of April, and often occupies the same +stone-heap, settling in the next shell. She is well-advised to start +work early and to be on neighbourly terms with the Osmia when the latter +is building; in fact, we shall soon see the terrible dangers to which +that same proximity exposes her dilatory rival in resin-work, Anthidium +bellicosum. + +The shell adopted in the great majority of cases is that of the +Common Snail, Helix aspersa. It is sometimes of full size, sometimes +half-developed. Helix nemoralis and H. caespitum, which are much +smaller, also supply suitable lodgings; and this would as surely apply +to any shell of sufficient capacity, if the places which I explore +possessed others, as witness a nest which my son Emile has sent me from +somewhere near Marseilles. This time, the Resin-bee is settled in Helix +algira, the most remarkable of our land-shells because of the width and +regularity of its spiral, which is copied from that of the Ammonites. +This magnificent nest, a perfect specimen of both the Snail's work and +the Bee's, deserves description before any other. + +For a distance of three centimetres (1.17 inches.--Translator's +Note.) from the mouth, the last spiral whorl contains nothing. At this +inconsiderable depth, a partition is clearly seen. The moderate diameter +of the passage accounts for the Anthidium's choice of this site to which +our eye can penetrate. In the common Snail-shell, whose cavity widens +rapidly, the insect establishes itself much farther back, so that, in +order to see the terminal partition, we must, as I have said, make a +lateral inlet. The position of this boundary-ceiling, which may come +farther forward or farther back, depends on the variable diameter of the +passage. The cells of the cocoons require a certain length and a certain +breadth, which the mother finds by going higher up or lower down in +the spiral, according to the shape of the shell. When the diameter is +suitable, the last whorl is occupied up to the orifice, where the final +lid appears, absolutely exposed to view. This is the case with the adult +Helix nemoralis and H. caespitum, and also with the young Common Snail. +We will not linger at present over this peculiarity, the importance of +which will become manifest shortly. + +Whether in the front or at the back of the spiral slope, the insect's +work ends in a facade of coarse mosaic, formed of small, angular bits +of gravel, firmly cemented with a gum the nature of which has to +be ascertained. It is an amber-coloured material, semi-transparent, +brittle, soluble in spirits of wine and burning with a sooty flame and a +strong smell of resin. From these characteristics it is evident that the +Bee prepares her gum with the resinous drops exuded by the Coniferae. + +I think that I am even able to name the particular plant, though I have +never caught the insect in the act of gathering its materials. Hard +by the stone-heaps which I turn over for my collections there is a +plentiful supply of brown-berried junipers. Pines are totally absent; +and the cypress only appears occasionally near the houses. Moreover, +among the vegetable remains which we shall see assisting in the +protection of the nest, we often find the juniper's catkins and needles. +As the resin-insect is economical of its time and does not fly far from +the quarters familiar to it, the gum must have been collected on the +shrub at whose foot the materials for the barricade have been gathered. +Nor is this merely a local circumstance, for the Marseilles nest abounds +in similar remnants. I therefore regard the juniper as the regular +resin-purveyor, without, however, excluding the pine, the cypress and +other Coniferae when the favourite shrub is absent. + +The bits of gravel in the lid are angular and chalky in the Marseilles +nest; they are round and flinty in most of the Serignan nests. In +making her mosaic, the worker pays no heed to the form or colour of its +component parts; she collects indiscriminately anything that is hard +enough and not too large. Sometimes she lights upon treasures that give +her work a more original character. The Marseilles nest shows me, neatly +encrusted amid the bits of gravel, a tiny whole landshell, Pupa cineres. +A nest in my own neighbourhood provides me with a pretty Snail-shell, +Helix striata, forming a rose-pattern in the middle of the mosaic. These +little artistic details remind me of a certain nest of Eumenes Amadei +(A Mason-wasp, forming the subject of an essay which has not yet been +published in English.--Translator's Note.) which abounds in small +shells. Ornamental shell-work appears to number its lovers among the +insects. + +After the lid of resin and gravel, an entire whorl of the spiral is +occupied by a barricade of incongruous remnants, similar to that which, +in the reeds, protects the row of cocoons of the Manicate Cotton-bee. +It is curious to see exactly the same defensive methods employed by two +builders of such different talents, one of whom handles flock, the +other gum. The nest from Marseilles has for its barricade bits of chalky +gravel, particles of earth, fragments of sticks, a few scraps of +moss and especially juniper-catkins and needles. The Serignan nests, +installed in Helix aspersa, have almost the same protective materials. I +see bits of gravel, the size of a lentil, and the catkins and needles of +the brown-berried juniper predominating. Next come the dry excretions of +the Snail and a few rare little land-shells. A similar jumble of more or +less everything found near the nest forms, as we know, the barricade +of the Manicate Cotton-bee, who is also an adept at using the Snail's +stercoral droppings after these have been dried in the sun. Let us +observe finally that these dissimilar materials are heaped together +without any cementing, just as the insect has picked them up. Resin +plays no part in the mass; and we have only to pierce the lid and turn +the shell upside down for the barricade to come dribbling to the ground. +To glue the whole thing together does not enter into the Resin-bee's +scheme. Perhaps such an expenditure of gum is beyond her means; perhaps +the barricade, if hardened into a solid block, would afterwards form an +invincible obstacle to the escape of the youngsters; perhaps again the +mass of gravel is an accessory rampart, run up roughly as a work of +secondary importance. + +Amid these doubtful matters, I see at least that the insect does not +look upon its barricade as indispensable. It employs it regularly in +the large shells, whose last whorl, too spacious to be used, forms an +unoccupied vestibule; it neglects it in the moderate shells, such as +Helix nemoralis, in which the resin lid is level with the orifice. My +excavations in the stone-heaps supply me with an almost equal number of +nests with and without defensive embankments. Among the Cotton-bees, the +Manicate Anthidium is not faithful either to her fort of little sticks +and stones; I know some of her nests in which cotton serves every +purpose. With both of them, the gravel rampart seems useful only in +certain circumstances, which I am unable to specify. + +On the other side of the outworks of the fortification, the lid and +barricade, are the cells set more or less far down in the spiral, +according to the diameter of the shell. They are bounded back and +front by partitions of pure resin, without any encrustations of mineral +particles. Their number is exceedingly restricted and is usually limited +to two. The front room, which is larger because the width of the passage +goes on increasing, is the abode of a male, superior in size to the +other sex; the less spacious back room contains a female. I have already +drawn attention in an earlier chapter to the wonderful problem submitted +for our consideration by this breaking up of the laying into couples +and this alternation of the males and females. Without calling for other +work than the transverse partitions, the broadening stairway of the +Snail-shell thus furnishes both sexes with house-room suited to their +size. + +The second Resin-bee that inhabits shells, Anthidium bellicosum, hatches +in July and works during the fierce heat of August. Her architecture +differs in no wise from that of her kinswoman of the springtime, so much +so that, when we find a tenanted Snail-shell in a hole in the wall or +under the stones, it is impossible to decide to which of the two species +the nest belongs. The only way to obtain exact information is to break +the shell and split the cocoons in February, at which time the nests +of the summer Resin-bee are occupied by larvae and those of the spring +Resin-bee by the perfect insect. If we shrink from this brutal +method, we are still in doubt until the cocoons open, so great is the +resemblance between the two pieces of work. + +In both cases, we find the same lodging, Snail-shells of every size and +every kind, just as they happen to come; the same resin lid, the inside +gritty with tiny bits of stone, the outside almost smooth and +sometimes ornamented with little shells; the same barricade--not always +present--of various kinds of rubbish; the same division into two rooms +of unequal size occupied by the two sexes. Everything is identical, down +to the purveyor of the gum, the brown-berried juniper. To say more about +the nest of the summer Resin-bee would be to repeat oneself. + +There is only one thing that requires further investigation. I do not +see the reason that prompts the two insects to leave the greater part of +their shell empty in front, instead of occupying it entirely up to the +orifice as the Osmia habitually does. As the mother's laying is broken +up into intermittent shifts of a couple of eggs apiece, is it necessary +that there should be a new home for each shift? Is the half-fluid resin +unsuitable for the wide-spanned roofs which would have to be constructed +when the diameter of the helical passage exceeded certain limits? Is +the gathering of the cement too wearisome a task to leave the Bee any +strength for making the numerous partitions which she would need if she +utilized the spacious final whorl? I find no answer to these questions. +I note the fact without interpreting it: when the shell is a large one, +the front part, almost the whole of the last whorl, remains an empty +vestibule. + +To the spring Resin-bee, Anthidium septemdentatum, this less than half +occupied lodging presents no drawbacks. A contemporary of the Osmia, +often her neighbour under the same stone, the gum-worker builds her nest +at the same period as the mud-worker; but there is no fear of mutual +encroachments, for the two Bees, working next door to each other, +watch their respective properties with a jealous eye. If attempts at +usurpation were to be made, the owner of the Snail-shell would know how +to enforce her rights as the first occupant. + +For the summer Resin-bee, A. bellicosum, the conditions are very +different. At the moment when the Osmia is building, she is still in the +larval, or at most in the nymphal stage. Her abode, which would not be +more absolutely silent if deserted, her shell, with its vast untenanted +porch, will not tempt the earlier Resin-bee, who herself wants +apartments right at the far end of the spiral, but it might suit the +Osmia, who knows how to fill the shell with cells up to the mouth. The +last whorl left vacant by the Anthidium is a magnificent lodging which +nothing prevents the mason from occupying. The Osmia does seize upon +it, in fact, and does so too often for the welfare of the unfortunate +late-comer. The final resin lid takes the place, for the Osmia, of +the mud stopper with which she cuts off at the back the portion of the +spiral too narrow for her labours. Upon this lid she builds her mass of +cells in so many storeys, after which she covers the whole with a +thick defensive plug. In short, the work is conducted as though the +Snail-shell contained nothing. + +When July arrives, this doubly-tenanted house becomes the scene of a +tragic conflict. Those below, on attaining the adult state, burst their +swaddling-bands, demolish their resin partitions, pass through the +gravel barricade and try to release themselves; those above, larvae +still or budding pupae, prisoners in their shells until the following +spring, completely block the way. To force a passage from the far-end +of those catacombs is beyond the strength of the Resin-bee, already +weakened by the effort of breaking out of her own nest. A few of the +Osmia's partitions are damaged, a few cocoons receive slight injuries; +and then, worn out with vain struggles, the captives abandon hope and +perish behind the impregnable wall of earth. And with them perish also +certain parasites, even less fit for the prodigious work of clearance: +Zonites and Chryses (Chrysis flammea), of whom the first are consumers +of provisions and the second of grubs. + +This lamentable ending of the Resin-bee, buried alive under the Osmia's +walls, is not a rare accident to be passed over in silence or mentioned +in a few words; on the contrary, it happens very often; and its +frequency suggests this thought: the school which sees in instinct an +acquired habit treats the slightest favourable occurrence in the course +of animal industry as the starting-point of an improvement which, +transmitted by heredity and becoming in time more and more accentuated, +at last grows into a settled characteristic common to the whole race. +There is, it is true, a total absence of positive proofs in support of +this theory; but it is stated with a wealth of hypothesis that leaves +a thousand loopholes: 'Granting that...Supposing that...It may +be...nothing need prevent us from believing... It is quite possible...' +Thus argued the master; and the disciples have not yet hit upon anything +better. + +'If the sky were to fall,' said Rabelais, 'the larks would all be +caught.' + +Yes, but the sky stays up; and the larks go on flying. + +'If things happened in such and such a way,' says our friend, 'instinct +may have undergone variations and modifications.' + +Yes, but are you quite sure that things happened as you say? + +I banish the word 'if' from my vocabulary. I suppose nothing, I take +nothing for granted; I pluck the brutal fact, the only thing that can be +trusted; I record it and then ask myself what conclusion rests upon +its solid framework. From the fact which I have related we may draw the +following inference: + +'You say that any modification profitable to the animal is transmitted +throughout a series of favoured ones who, better equipped with tools, +better endowed with aptitudes, abandon the ancient usages and replace +the primitive species, the victim of the struggle for life. You declare +that once, in the dim distance of the ages, a Bee found herself by +accident in possession of a dead Snail-shell. The safe and peaceful +lodging pleased her fancy. On and on went the hereditary liking; and the +Snail-shell proved more and more agreeable to the insect's descendants, +who began to look for it under the stones, so that later generations, +with the aid of habit, ended by adopting it as the ancestral dwelling. +Again by accident, the Bee happened upon a drop of resin. It was soft, +plastic, well-suited for the partitioning of the Snail-shell; it soon +hardened into a solid ceiling. The Bee tried the resinous gum and +benefited by it. Her successors also benefited by it, especially after +improving it. Little by little, the rubble-work of the lid and of the +gravel barricade was invented: an enormous improvement, of which the +race did not fail to take advantage. The defensive fortification was the +finishing-touch to the original structure. Here we have the origin and +development of the instinct of the Resin-bees who make their home in +Snail-shells.' + +This glorious genesis of insect ways and means lacks just one little +thing: probability. Life everywhere, even among the humble, has two +phases: its share of good and its share of evil. Avoiding the latter +and seeking the former is the rough balance-sheet of life's actions. +Animals, like ourselves, have their portion of the sweet and the bitter: +they are just as anxious to reduce the second as to increase the first; +for, with them as with us, + + De malheurs evites le bonheur se compose. + (Bad luck missed is good luck gained.) + +If the Bee has so faithfully handed down her casual invention of a resin +nest built inside a Snail-shell, then there is no denying that she must +have just as faithfully handed down the means of averting the terrible +danger of belated hatchings. A few mothers, escaping at rare intervals +from the catacombs blocked by the Osmiae, must have retained a lively +memory, a powerful impression of their desperate struggle through the +mass of earth; they must have inspired their descendants with a dread +of those vast dwellings where the stranger comes afterwards and builds; +they must have taught them by habit the means of safety, the use of the +medium-sized shell, which the nest fills to the mouth. So far as the +prosperity of the race was concerned, the discontinuance of the system +of empty vestibules was far more important than the invention of the +barricade, which is not altogether indispensable: it would have saved +them from perishing miserably, behind impenetrable walls, and would have +considerably increased the numbers of their posterity. + +Thousands and thousands of experiments have been made throughout the +ages with Snail-shells of average dimensions: the thing is certain, +because I find many of them to-day. Well, have these life-saving +experiments, with their immense importance to the race, become general +by hereditary bequest? Not at all: the Resin-bee persists in using big +Snail-shells just as though her ancestors had never known the danger of +the Osmia-blocked vestibule. Once these facts are duly recognized, the +conclusion is irresistible: it is obvious that, as the insect does not +hand down the casual modification tending towards the avoidance of +what is to its disadvantage, neither does it hand down the modification +leading to the adoption of what is to its advantage. However lively the +impression made upon the mother, the accidental leaves no trace in the +offspring. Chance plays no part in the genesis of the instincts. + +Next to these tenants of the Snail-shells we have two other Resin-bees +who never come to the shells for a cabin for their nests. They are +Anthidium quadrilobum, LEP., and A. Latreillii, LEP., both exceedingly +uncommon in my district. If we meet them very rarely, however, this may +well be due to the difficulty of seeing them; for they lead extremely +solitary and wary lives. A warm nook under some stone or other; the +deserted streets of an Ant-hill in a sun-baked bank; a Beetle's vacant +burrow a few inches below the ground; in short, a cavity of some +sort, perhaps arranged by the Bee's own care: these are the only +establishments which I know them to occupy. And here, with no other +shelter than the cover of the refuge, they build a mass of cells joined +together and grouped into a sphere, which, in the case of the Four-lobed +Resin-bee, attains the size of a man's fist and, in that of Latreille's +Resin-bee, the size of a small apple. + +At first sight, we remain very uncertain as to the nature of the strange +ball. It is brown, rather hard, slightly sticky, with a bituminous +smell. Outside are encrusted a few bits of gravel, particles of earth, +heads of large-sized Ants. This cannibal trophy is not a sign of +barbarous customs: the Bee does not decapitate Ants to adorn her hut. +An inlayer, like her colleagues of the Snail-shell, she gathers any hard +granule near at hand capable of strengthening her work; and the dried +skulls of Ants, which are frequent around about her abode, are in her +eyes building-stones of equal value to the pebbles. One and all employ +whatever they can find without much seeking. The inhabitant of the +shell, in order to construct her barricade, makes shift with the dry +excrement of the nearest Snail; the denizen of the flat stones and of +the roadside banks frequented by the Ants does what she can with the +heads of the defunct and, should these be lacking, is ready to replace +them with something else. Moreover, the defensive inlaying is slight; +we see that the insect attaches no great importance to it and has every +confidence in the stout wall of the home. + +The material of which the work is made at first suggests some rustic +wax, much coarser than that of the Bumble-bees, or rather some tar +of unknown origin. We think again and then recognize in the puzzling +substance the semitransparent fracture, the quality of becoming soft +when exposed to heat and of burning with a smoky flame, the solubility +in spirits of wine--in short, all the distinguishing characteristics +of resin. Here then are two more collectors of the exudations of the +Coniferae. At the points where I find their nests are Aleppo pines, +cypresses, brown-berried junipers and common junipers. Which of the four +supplies the mastic? There is nothing to tell us. Nor is there anything +to explain how the native amber-colour of the resin is replaced in the +work of both Bees by a dark-brown hue resembling that of pitch. Does the +insect collect resin impaired by the weather, soiled by the sanies of +rotten wood? When kneading it, does it mix some dark ingredient with it? +I look upon this as possible, but not as proved, since I have never seen +the Bee collecting her resin. + +While this point escapes me, another of higher interest appears most +plainly; and that is the large amount of resinous material used in a +single nest, especially in that of Anthidium quadrilobum, in which I +have counted as many as twelve cells. The nest of the Mason-bee of +the Pebbles is hardly more massive. For so costly an establishment, +therefore, the Resin-bee collects her pitch on the dead pine as +copiously as the Mason-bee collects her mortar on the macadamized +road. Her workshop no longer shows us the niggardly partitioning of a +Snail-shell with two or three drops of resin; what we see is the whole +building of the house, from the basement to the roof, from the thick +outer walls to the partitions of the rooms. The cement expended would +be enough to divide hundreds of Snail-shells, wherefore the title of +Resin-bee is due first and foremost to this master-builder in pitch. +Honourable mention should be awarded to A. Latreillii, who rivals +her fellow-worker as far as her smaller stature permits. The other +manipulators of resin, those who build partitions in Snail-shells, come +third, a very long way behind. + +And now, with the facts to support us, let us philosophize a little. +We have here, recognized as of excellent standard by all the expert +classifiers, so fastidious in the arrangement of their lists, a generic +group, called Anthidium, containing two guilds of workers entirely +dissimilar in character: the cotton-fullers and the resin-kneaders. It +is even possible that other species, when their habits are better known, +will come and increase this variety of manufactures. I confine myself to +the little that I know and ask myself in what the manipulator of cotton +differs from the manipulator of resin as regards tools, that is to +say, organs. Certainly, when the genus Anthidium was set down by +the classifiers, they were not wanting in scientific precision: they +consulted, under the lens of the microscope, the wings, the mandibles, +the legs, the harvesting-brush, in short, all the details calculated +to assist the proper delimitation of the group. After this minute +examination by the experts, if no organic differences stand revealed, +the reason is that they do not exist. Any dissimilarity of structure +could not escape the accurate eyes of our learned taxonomists. The +genus, therefore, is indeed organically homogeneous; but industrially it +is thoroughly heterogeneous. The implements are the same and the work is +different. + +That eminent Bordeaux entomologist, Professor Jean Perez, to whom I +communicated the misgivings aroused in my mind by the contradictory +nature of my discoveries, thinks that he has found the solution of the +difficulty in the conformation of the mandibles. I extract the following +passage from his volume, "Les Abeilles": + +'The cotton-pressing females have the edge of their mandibles cut out +into five or six little teeth, which make an instrument admirably suited +for scraping and removing the hairs from the epidermis of the plants. It +is a sort of comb or teasel. The resin-kneading females have the edge of +the mandible not toothed, but simply curved; the tip alone, preceded +by a notch which is pretty clearly marked in some species, forms a real +tooth; but this tooth is blunt and does not project. The mandible, in +short, is a kind of spoon perfectly fitted to remove the sticky matter +and to shape it into a ball.' + +Nothing better could be said to explain the two sorts of industry: in +the one case, a rake which gathers the wool; in the other, a spoon +which scoops up the resin. I should have left it at that and felt quite +content without further investigation, if I had not had the curiosity to +open my boxes and, in my turn, to take a good look, side by side, at +the workers in cement and the workers in cotton. Allow me, my learned +master, to whisper in your ear what I saw. + +The first that I examine is Anthidium septemdentatum. A spoon: yes, it +is just that. Powerful mandibles, shaped like an isosceles triangle, +flat above, hollowed out below; and no indentations, none whatsoever. +A splendid tool, as you say, for gathering the viscous pellet; quite as +efficacious in its kind of work as is the rake of the toothed mandibles +for gathering cotton. Here certainly is a creature potently-gifted, even +though it be for a poor little task, the scooping up of two or three +drops of glue. + +Things are not quite so satisfactory with the second Resin-bee of the +Snail-shells, A. bellicosum. I find that she has three teeth to her +mandibles. Still, they are slight and project very little. Let us say +that this does not count, even though the work is exactly the same. +With A. quadrilobum the whole thing breaks down. She, the queen of +Resin-bees; she, who collects a lump of mastic the size of one's fist, +enough to subdivide hundreds of her kinswomen's Snail-shells: well, she, +by way of a spoon, carries a rake! On the wide edges of her mandibles +stand four teeth, as long and pointed as those of the most zealous +cotton-gleaner. A. florentinum, that mighty manufacturer of +cotton-goods, can hardly rival her in respect of combing-tools. And +nevertheless, with her toothed implement, a sort of saw, the Resin-bee +collects her great heap of pitch, load by load; and the material is +carried not rigid, but sticky, half-fluid, so that it may amalgamate +with the previous lots and be fashioned into cells. + +A. Latreillii, without having a very large implement, also bears witness +to the possibility of heaping up soft resin with a rake; she arms her +mandibles with three or four sharply-cut teeth. In short, out of four +Resin-bees, the only four that I know, one is armed with a spoon, if +this expression be really suited to the tool's function; the three +others are armed with a rake; and it so happens that the most copious +heap of resin is just the work of the rake with the most teeth to it, +a tool suited to the cotton-reapers, according to the views of the +Bordeaux entomological expert. + +No, the explanation that appealed to me so much at first is not +admissible. The mandible, whether supplied with teeth or not, does not +account at all for the two manufactures. May we, in this predicament, +have recourse to the general structure of the insect, although this is +not distinctive enough to be of much use to us? Not so either; for, +in the same stone-heaps where the Osmia and the two Resin-bees of the +Snail-shells work, I find from time to time another manipulator of +mastic who bears no structural relationship whatever to the genus +Anthidium. It is a small-sized Mason-wasp, Odynerus alpestris, SAUSS. +She builds a very pretty nest with resin and gravel in the shells of +the young Common Snail, of Helix nemoralis and sometimes of Bulimulus +radiatus. I will describe her masterpiece on some other occasion. To +one acquainted with the genus Odynerus, any comparison with the Anthidia +would be an inexcusable error. In larval diet, in shape, in habits, they +form two dissimilar groups, very far removed one from the other. The +Anthidia feed their offspring on honey-bread; the Odyneri feed it on +live prey. Well, with her slender form, her weakly frame, in which +the most clear-seeing eye would seek in vain for a clue to the trade +practised, the Alpine Odynerus, the game-lover, uses pitch in the same +way as the stout and massive Resin-bee, the honey-lover. She even uses +it better, for her mosaic of tiny pebbles is much prettier than the +Bee's and no less solid. With her mandibles, this time neither spoon nor +rake, but rather a long forceps slightly notched at the tip, she gathers +her drop of sticky matter as dexterously as do her rivals with their +very different outfit. Her case will, I think, persuade us that neither +the shape of the tool nor the shape of the worker can explain the work +done. + +I will go further: I ask myself in vain the reason of this or that trade +in the case of a fixed species. The Osmiae make their partitions with +mud or with a paste of chewed leaves; the Mason-bees build with cement; +the Pelopaeus-wasps fashion clay pots; the Megachiles made disks +cut from leaves into urns; the Anthidia felt cotton into purses; +the Resin-bees cement together little bits of gravel with gum; the +Carpenter-bees and the Lithurgi bore holes in timber; the Anthophorae +tunnel the roadside slopes. Why all these different trades, to say +nothing of the others? How are they prescribed for the insect, this one +rather than that? + +I foresee the answer: they are prescribed by the organization. An insect +excellently equipped for gathering and felting cotton is ill-equipped +for cutting leaves, kneading mud or mixing resin. The tool in its +possession decides its trade. + +This is a very simple explanation, I admit, and one within the scope +of everybody: in itself a sufficient recommendation for any one who +has neither the inclination nor the time to undertake a more thorough +investigation. The popularity of certain speculative views is due +entirely to the easy food which they provide for our curiosity. They +save us much long and often irksome study; they impart a veneer of +general knowledge. There is nothing that achieves such immediate success +as an explanation of the riddle of the universe in a word or two. The +thinker does not travel so fast: content to know little so that he may +know something, he limits his field of search and is satisfied with +a scanty harvest, provided that the grain be of good quality. Before +agreeing that the tool determines the trade, he wants to see things with +his own eyes; and what he observes is far from confirming the sweeping +statement. Let us share his doubts for a moment and look into matters +more closely. + +Franklin left us a maxim which is much to the point here. He said that a +good workman should be able to plane with a saw and to saw with a plane. +The insect is too good a workman not to follow the advice of the sage +of Boston. Its industry abounds in instances where the plane takes the +place of the saw, or the saw of the plane; its dexterity makes good the +inadequacy of the implement. To go no further, have we not just seen +different artisans collecting and using pitch, some with spoons, others +with rakes, others again with pincers? Therefore, with such equipment +as it possesses, the insect would be capable of abandoning cotton for +leaves, leaves for resin, resin for mortar, if some predisposition of +talent did not make it keep to its speciality. + +These few lines, which are the outcome not of a heedless pen but of +mature reflection, will set people talking of hateful paradoxes. We +will let them talk and we will submit the following proposition to our +adversaries: take an entomologist of the highest merit, a Latreille +(Pierre Andre Latreille (1762-1833), one of the founders of modern +entomological science.--Translator's Note.), for instance, versed in all +the details of the structure of insects but utterly unacquainted with +their habits. He knows the dead insect better than anybody, but he has +never occupied himself with the living insect. As a classifier, he is +beyond compare; and that is all. We ask him to examine a Bee, the first +that comes to hand, and to name her trade from her tools. + +Come, be honest: could he? Who would dare put him to such a test? Has +personal experience not fully convinced us that the mere examination +of the insect can tell us nothing about its particular industry? The +baskets on its legs and the brush on its abdomen will certainly inform +us that it collects honey and pollen; but its special art will remain an +utter secret, notwithstanding all the scrutiny of the microscope. In our +own industries, the plane denotes the joiner, the trowel the mason, the +scissors the tailor, the needle the seamstress. Are things the same +in animal industry? Just show us, if you please, the trowel that is +a certain sign of the mason-insect, the chisel that is a positive +characteristic of the carpenter-insect, the iron that is an authentic +mark of the pinking-insect; and as you show them, say: + +'This one cuts leaves; that one bores wood; that other mixes cement.' + +And so on, specifying the trade from the tool. + +You cannot do it, no one can; the worker's speciality remains an +impenetrable secret until direct observation intervenes. Does not +this incapacity, even of the most expert, proclaim loudly that animal +industry, in its infinite variety, is due to other causes besides the +possession of tools? Certainly, each of those specialists requires +implements; but they are rough and ready implements, good for all sorts +of purposes, like the tool of Franklin's workman. The same notched +mandible that reaps cotton, cuts leaves and moulds pitch also kneads +mud, scrapes decayed wood and mixes mortar; the same tarsus that +manufactures cotton and disks cut out of leaves is no less clever at the +art of making earthen partitions, clay turrets and gravel mosaics. + +What then is the reason of these thousand industries? In the light of +facts, I can see but one: imagination governing matter. A primordial +inspiration, a talent antecedent to the actual form, directs the tool +instead of being subordinate to it. The instrument does not determine +the manner of industry; the tool does not make the workman. At the +beginning there is an object, a plan, in view of which the animal acts, +unconsciously. Have we eyes to see with, or do we see because we have +eyes? Does the function create the organ, or the organ the function? Of +the two alternatives, the insect proclaims the first. It says: + +'My industry is not imposed upon me by the implement which I possess; +what I do is to use the implement, such as it is, for the talent with +which I am gifted.' + +It says to us, in its own way: + +'The function has determined the organ; vision is the reason of the +eye.' + +In short, it repeats to us Virgil's profound reflection: + +'Mens agitat molem'; 'Mind moves matter.' + + + + +CHAPTER 11. THE POISON OF THE BEE. + +I have discussed elsewhere the stings administered by the Wasps to +their prey. Now chemistry comes and puts a spoke in the wheel of our +arguments, telling us that the poison of the Bees is not the same as +that of the Wasps. The Bees' is complex and formed of two elements, acid +and alkaline. The Wasps' possess only the acid element; and it is to +this very acidity and not to the 'so-called' skill of the operators that +the preservation of the provisions is due. (The author's numerous essays +on the Wasps will form the contents of later works. In the meantime, cf. +"Insect Life," by J.H. Fabre, translated by the author of "Mademoiselle +Mori": chapters 4 to 12, and 14 to 18; and "The Life and Love of the +Insect," by J. Henri Fabre, translated by Alexander Teixeira de Mattos: +chapters 11, 12 and 17.--Translator's Note.) + +Admitting that there is a difference in the nature of the venom, I fail +to see that this has any bearing on the problem in hand. I can inoculate +with various liquids--acids, weak nitric acid, alkalis, ammonia, neutral +bodies, spirits of wine, essence of turpentine--and obtain conditions +similar to those of the victims of the predatory insects, that is to +say, inertia with the persistence of a dull vitality betrayed by +the movements of the mouth-parts and antennae. I am not, of course, +invariably successful, for there is neither delicacy nor precision in +my poisoned needle and the wound which it makes does not bear comparison +with the tiny puncture of the unerring natural sting; but, after all, +it is repeated often enough to put the object of my experiment beyond +doubt. I should add that, to achieve success, we must have a subject +with a concentrated ganglionic column, such as the Weevil, the +Buprestis, the Dung-beetle and others. Paralysis is then obtained with +but a single prick, made at the point which the Cerceris has revealed +to us, the point at which the corselet joins the rest of the thorax. In +that case, the least possible quantity of the acrid liquid is instilled, +a quantity too small to endanger the patient's life. With scattered +nervous centres, each requiring a separate operation, this method is +impracticable: the victim would die of the excess of corrosive fluid. I +am quite ashamed to have to recall these old experiments. Had they been +resumed and carried on by others of greater authority than I, we should +have escaped the objections of chemistry. + +When light is so easy to obtain, why go in search of scientific +obscurity? Why talk of acid or alkaline reactions, which prove nothing, +when it is so simple to have recourse to facts, which prove everything? +Before declaring that the hunting insects' poison has preservative +properties merely because of its acid qualities, it would have been well +to enquire if the sting of a Bee, with its acid and its alkali, could +not perchance produce the same effects as that of the paralyser, whose +skill is categorically denied. The chemists never gave this a thought. +Simplicity is not always welcome in our laboratories. It is my duty to +repair that little omission. I propose to enquire if the poison of the +Bee, the chief of the Apidae, is suitable for a surgery that paralyses +without killing. + +The enquiry bristles with difficulties, though this is no reason for +abandoning it. First and foremost, I cannot possibly operate with the +Bee just as I catch her. Time after time I make the attempt, without +once succeeding; and patience becomes exhausted. The sting has to +penetrate at a definite point, exactly where the Wasp's sting would +have entered. My intractable captive tosses about angrily and stings at +random, never where I wish. My fingers get hurt even oftener than the +patient. I have only one means of gaining a little control over the +indomitable dart; and that is to cut off the Bee's abdomen with my +scissors, to seize the stump instantly with a fine forceps and to apply +the tip at the spot where the sting is to enter. + +Everybody knows that the Bee's abdomen needs no orders from the head +to go on drawing its weapon for a few instants longer and to avenge +the deceased before being itself overcome with death's inertia. This +vindictive persistency serves me to perfection. There is another +circumstance in my favour: the barbed sting remains where it is, which +enables me to ascertain the exact spot pierced. A needle withdrawn +as soon as inserted would leave me doubtful. I can also, when the +transparency of the tissues permits, perceive the direction of the +weapon, whether perpendicular and favourable to my plans, or slanting +and therefore valueless. Those are the advantages. + +The disadvantages are these: the amputated abdomen, though more +tractable than the entire Bee, is still far from satisfying my wishes. +It gives capricious starts and unexpected pricks. I want it to sting +here. No, it balks my forceps and goes and stings elsewhere: not very +far away, I admit; but it takes so little to miss the nerve-centre which +we wish to get at. I want it to go in perpendicularly. No, in the +great majority of cases it enters obliquely and passes only through the +epidermis. This is enough to show how many failures are needed to make +one success. + +Nor is this all. I shall be telling nobody anything new when I recall +the fact that the Bee's sting is very painful. That of the hunting +insects, on the contrary, is in most cases insignificant. My skin, which +is no less sensitive than another's, pays no attention to it: I handle +Sphex, Ammophilae and Scoliae without heeding their lancet-pricks. I +have said this before; I remind the reader of it because of the matter +in hand. In the absence of well-known chemical or other properties, we +have really but one means of comparing the two respective poisons; and +that is the amount of pain produced. All the rest is mystery. Besides, +no poison, not even that of the Rattlesnake, has hitherto revealed the +cause of its dread effects. + +Acting, therefore, under the instruction of that one guide, pain, I +place the Bee's sting far above that of the predatory insects as an +offensive weapon. A single one of its thrusts must equal and often +surpass in efficaciousness the repeated wounds of the other. For all +these reasons--an excessive display of energy; the variable quantity of +the virus inoculated by a wriggling abdomen which no longer measures the +emission by doses; a sting which I cannot direct as I please; a wound +which may be deep or superficial, the weapon entering perpendicularly or +obliquely, touching the nerve-centres or affecting only the surrounding +tissues--my experiments ought to produce the most varied results. + +I obtain, in fact, every possible kind of disorder: ataxy, temporary +disablement, permanent disablement, complete paralysis, partial +paralysis. Some of my stricken victims recover; others die after a brief +interval. It would be an unnecessary waste of space to record in this +volume my hundred and one attempts. The details would form tedious +reading and be of very little advantage, as in this sort of study it +is impossible to marshal one's facts with any regularity. I will, +therefore, sum them up in a few examples. + +A colossal member of the Grasshopper tribe, the most powerful in my +district, Decticus verrucivorus (This Decticus has received its specific +name of verrucivorus, or Wart-eating, because it is employed by +the peasants in Sweden and elsewhere to bite off the warts on their +fingers.--Translator's Note.), is pricked at the base of the neck, on +the line of the fore-legs, at the median point. The prick goes straight +down. The spot is the same as that pierced by the sting of the slayer +of Crickets and Ephippigers. (A species of Green Grasshopper. The Sphex +paralyses Crickets and Grasshoppers to provide food for her grubs. Cf. +"Insect Life": chapters 6 to 12.--Translator's Note.) The giantess, as +soon as stung, kicks furiously, flounders about, falls on her side and +is unable to get up again. The fore-legs are paralysed; the others are +capable of moving. Lying sideways, if not interfered with, the insect in +a few moments gives no signs of life beyond a fluttering of the antennae +and palpi, a pulsation of the abdomen and a convulsive uplifting of the +ovipositor; but, if irritated with a slight touch, it stirs its four +hind-legs, especially the third pair, those with the big thighs, which +kick vigorously. Next day, the condition is much the same, with an +aggravation of the paralysis, which has now attacked the middle-legs. +On the day after that, the legs do not move, but the antennae, the palpi +and the ovipositor continue to flutter actively. This is the condition +of the Ephippiger stabbed three times in the thorax by the Languedocian +Sphex. One point alone is missing, a most important point: the long +persistence of a remnant of life. In fact, on the fourth day, the +Decticus is dead; her dark colour tells me so. + +There are two conclusions to be drawn from this experiment and it is +well to emphasise them. First, the Bee's poison is so active that a +single dagger-thrust aimed at a nervous centre kills in four days one +of the largest of the Orthoptera (An order of insects including the +Grasshoppers, Locusts, Cockroaches, Mantes and Earwigs, in addition +to the Stick- and Leaf-insects, Termites, Dragon-flies, May-flies, +Book-lice and others.--Translator's Note.), though an insect of powerful +constitution. Secondly, the paralysis at first affects only the legs +whose ganglion is attacked; next, it spreads slowly to the second +pair; lastly, it reaches the third. The local effect is diffused. This +diffusion, which might well take place in the victims of the predatory +insects, plays no part in the latters' method of operation. The egg, +which will be laid immediately afterwards, demands the complete inertia +of the prey from the outset. Hence all the nerve-centres that govern +locomotion must be numbed instantaneously by the virus. + +I can now understand why the poison of the predatory Wasps is +comparatively painless in its effects. If it possessed the strength of +that of the Bee, a single stab would impair the vitality of the prey, +while leaving it for some days capable of violent movements that would +be very dangerous to the huntress and especially to the egg. More +moderate in its action, it is instilled at the different nervous +centres, as is the case more particularly with the caterpillars. +(Caterpillars are the prey of the Ammophila, which administers a +separate stab to each of the several ganglia.--Translator's Note.) +In this way, the requisite immobility is obtained at once; and, +notwithstanding the number of wounds, the victim is not a speedy corpse. +To the marvels of the paralysers' talent we must add one more: their +wonderful poison, the strength of which is regulated by delicate doses. +The Bee revenging herself intensifies the virulence of her poison; the +Sphex putting her grubs' provender to sleep weakens it, reduces it to +what is strictly necessary. + +One more instance of nearly the same kind. I prefer to take my subjects +from among the Orthoptera, which, owing to their imposing size and the +thinness of their skin at the points to be attacked, lend themselves +better than other insects to my delicate manipulations. The armour of +a Buprestis, the fat blubber of a Rosechafer-grub, the contortions of +a caterpillar present almost insuperable obstacles to the success of +a sting which it is not in my power to direct. The insect which I +now offer to the Bee's lancet is the Great Green Grasshopper (Locusta +viridissima), the adult female. The prick is given in the median line of +the fore-legs. + +The effect is overwhelming. For two or three seconds the insect writhes +in convulsions and then falls on its side, motionless throughout, +save in the ovipositor and the antennae. Nothing stirs so long as the +creature is left alone; but, if I tickle it with a hair-pencil, the four +hind-legs move sharply and grip the point. As for the fore-legs, smitten +in their nerve-centre, they are quite lifeless. The same condition +is maintained for three days longer. On the fifth day, the creeping +paralysis leaves nothing free but the antennae waving to and fro and +the abdomen throbbing and lifting up the ovipositor. On the sixth, the +Grasshopper begins to turn brown; she is dead. Except that the vestige +of life is more persistent, the case is the same as that of the +Decticus. If we can prolong the duration, we shall have the victim of +the Sphex. + +But first let us look into the effect of a prick administered elsewhere +than opposite the thoracic ganglia. I cause a female Ephippiger to be +stung in the abdomen, about the middle of the lower surface. The patient +does not seem to trouble greatly about her wound: she clambers gallantly +up the sides of the bell-jar under which I have placed her; she goes on +hopping as before. Better still, she sets about browsing the vine-leaf +which I have given her for her consolation. A few hours pass and the +whole thing is forgotten. She has made a rapid and complete recovery. + +A second is wounded in three places on the abdomen: in the middle and on +either side. On the first day, the insect seems to have felt nothing; +I see no sign of stiffness in its movements. No doubt it is suffering +acutely; but these stoics keep their troubles to themselves. Next day, +the Ephippiger drags her legs a little and walks somewhat slowly. Two +days more; and, when laid on her back, she is unable to turn over. On +the fifth day, she succumbs. This time, I have exceeded the dose; the +shock of receiving three stabs was too much for her. + +And so with the others, down to the sensitive Cricket, who, pricked once +in the abdomen, recovers in one day from the painful experience and goes +back to her lettuce-leaf. But, if the wound is repeated a few times, +death ensues within a more or less short period. I make an +exception, among those who pay tribute to my cruel curiosity, of the +Rosechafer-grubs, who defy three and four needle-thrusts. They will +collapse suddenly and lie outstretched, flabby and lifeless; and, just +when I am thinking them dead or paralysed, the hardy creatures will +recover consciousness, move along on their backs (This is the usual mode +of progression of the Cetonia- or Rosechafer-grub. Cf. "The Life and +Love of the Insect": chapter 11.--Translator's Note.), bury themselves +in the mould. I can obtain no precise information from them. True, their +thinly scattered cilia and their breastplate of fat form a palisade and +a rampart against the sting, which nearly always enters only a little +way and that obliquely. + +Let us leave these unmanageable ones and keep to the Orthoperon, which +is more amenable to experiment. A dagger-thrust, we were saying, kills +it if directed upon the ganglia of the thorax; it throws it into a +transient state of discomfort if directed upon another point. It is, +therefore, by its direct action upon the nervous centres that the poison +reveals its formidable properties. + +To generalize and say that death is always near at hand when the sting +is administered in the thoracic ganglia would be going too far: it +occurs frequently, but there are a good many exceptions, resulting from +circumstances impossible to define. I cannot control the direction of +the sting, the depth attained, the quantity of poison shed; and the +stump of the Bee is very far from making up for my shortcomings. We have +here not the cunning sword-play of the predatory insect, but a casual +blow, ill-placed and ill-regulated. Any accident is possible, therefore, +from the gravest to the mildest. Let us mention some of the more +interesting. + +An adult Praying Mantis (Mantis religiosa, so-called because the toothed +fore-legs, in which it catches and kills its prey, adopt, when folded, +an attitude resembling that of prayer.--Translator's Note.) is pricked +level with the attachment of the predatory legs. Had the wound been in +the centre, I should have witnessed an occurrence which, although I have +seen it many times, still arouses my liveliest emotion and surprise. +This is the sudden paralysis of the warrior's savage harpoons. No +machinery stops more abruptly when the mainspring breaks. As a rule, the +inertia of the predatory legs attacks the others in the course of a day +or two; and the palsied one dies in less than a week. But the present +sting is not in the exact centre. The dart has entered near the base +of the right leg, at less than a millimetre (.039 inch.--Translator's +Note.) from the median point. That leg is paralysed at once; the other +is not; and the insect employs it to the detriment of my unsuspecting +fingers, which are pricked to bleeding-point by the spike at the +tip. Not until to-morrow is the leg which wounded me to-day rendered +motionless. This time, the paralysis goes no farther. The Mantis +moves along quite well, with her corselet proudly raised, in her usual +attitude; but the predatory fore-arms, instead of being folded against +the chest, ready for attack, hang lifeless and open. I keep the cripple +for twelve days longer, during which she refuses all nourishment, being +incapable of using her tongs to seize the prey and lift it to her mouth. +The prolonged abstinence kills her. + +Some suffer from locomotor ataxy. My notes recall an Ephippiger who, +pricked in the prothorax away from the median line, retained the use +of her six limbs without being able to walk or climb for lack of +co-ordination in her movements. A singular awkwardness left her wavering +between going back and going forward, between turning to the right and +turning to the left. + +Some are smitten with semiparalysis. A Cetonia-grub, pricked away from +the centre on a level with the fore-legs, has her right side flaccid, +spread out, incapable of contracting, while the left side swells, +wrinkles and contracts. Since the left half no longer receives the +symmetrical cooperation of the right half, the grub, instead of curling +into the normal volute, closes its spiral on one side and leaves it wide +open on the other. The concentration of the nervous apparatus, poisoned +by the venom down one side of the body only, a longitudinal half, +explains this condition, which is the most remarkable of all. + +There is nothing to be gained by multiplying these examples. We have +seen pretty clearly the great variety of results produced by the +haphazard sting of a Bee's abdomen; let us now come to the crux of the +matter. Can the Bee's poison reduce the prey to the condition required +by the predatory Wasp? Yes, I have proved it by experiment; but the +proof calls for so much patience that it seemed to me to suffice when +obtained once for each species. In such difficult conditions, with a +poison of excessive strength, a single success is conclusive proof; the +thing is possible so long as it occurs once. + +A female Ephippiger is stung at the median point, just a little in front +of the fore-legs. Convulsive movements lasting for a few seconds +are followed by a fall to one side, with pulsations of the abdomen, +flutterings of the antennae and a few feeble movements of the legs. The +tarsi cling firmly to the hair-pencil which I hold out to them. I place +the insect on its back. It lies motionless. Its state is absolutely the +same as that to which the Languedocian Sphex (Cf. "Insect Life": chapter +10.--Translator's Note.) reduces her Ephippigers. For three weeks on +end, I see repeated in all its details the spectacle to which I have +been accustomed in the victims extracted from the burrows or taken from +the huntress: the wide-open mandibles, the quivering palpi and tarsi, +the ovipositor shuddering convulsively, the abdomen throbbing at long +intervals, the spark of life rekindled at the touch of a pencil. In +the fourth week, these signs of life, which have gradually weakened, +disappear, but the insect still remains irreproachably fresh. At last +a month passes; and the paralysed creature begins to turn brown. It is +over; death has come. + +I have the same success with a Cricket and also with a Praying Mantis. +In all three cases, from the point of view of long-maintained freshness +and of the signs of life proved by slight movements, the resemblance +between my victim and those of the predatory insects is so great that no +Sphex and no Tachytes would have disowned the product of my devices. My +Cricket, my Ephippiger, my Mantis had the same freshness as theirs; they +preserved it as theirs did for a period amply sufficient to allow of +the grubs' complete evolution. They proved to me, in the most conclusive +manner, they prove to all whom it may interest, that the poison of the +Bees, leaving its hideous violence on one side, does not differ in its +effects from the poison of the predatory Wasps. Are they alkaline or +acid? The question is an idle one in this connection. Both of them +intoxicate, derange, torpify the nervous centres and thus produce either +death or paralysis, according to the method of inoculation. For the +moment, that is all. No one is yet able to say the last word on the +actions of those poisons, so terrible in infinitesimal doses. But on the +point under discussion we need no longer be ignorant: the Wasp owes the +preservation of her grub's provisions not to any special qualities of +her poison but to the extreme precision of her surgery. + +A last and more plausible objection is that raised by Darwin when he +said that there were no fossil remains of instincts. And, if there were, +O master, what would they teach us? Not very much more than what we +learn from the instincts of to-day. Does not the geologist make the +erstwhile carcases live anew in our minds in the light of the world as +we see it? With nothing but analogy to guide them, he describes how +some saurian lived in the jurassic age; there are no fossil remains of +habits, but nevertheless he can tell us plenty about them, things worthy +of credence, because the present teaches him the past. Let us do a +little as he does. + +I will suppose a precursor of the Calicurgi (The Calicurgus, or +Pompilus, is a Hunting Wasp, feeding her larvae on Spiders. Cf. "The +Life and Love of the Insect": chapter 12.--Translator's Note.) dwelling +in the prehistoric coal-forests. Her prey was some hideous Scorpion, +that first-born of the Arachnida. How did the Hymenopteron master the +terrible prey? Analogy tells us, by the methods of the present slayer of +Tarantulae. It disarmed the adversary; it paralysed the venomous sting +by a stroke administered at a point which we could determine for certain +by the animal's anatomy. Unless this was the way it happened, the +assailant must have perished, first stabbed and then devoured by the +prey. There is no getting away from it: either the precursor of the +Calicurgi, that slaughterer of Scorpions, knew her trade thoroughly, or +else the continuation of her race became impossible, even as it would +be impossible to keep up the race of the Tarantula-killer without the +dagger-thrust that paralyses the Spider's poison-fangs. The first who, +greatly daring, pinked the Scorpion of the coal-seams was already an +expert fencer; the first to come to grips with the Tarantula had an +unerring knowledge of her dangerous surgery. The least hesitation, the +slightest speculation; and they were lost. The first teacher would also +have been the last, with no disciples to take up her work and perfect +it. + +But fossil instincts, they insist, would show us intermediary stages, +first, second and third rungs; they would show us the gradual passing +from the casual and very incorrect attempt to the perfect practice, the +fruit of the ages; with their accidental differences, they would give +us terms of comparison wherewith to trace matters from the simple to the +complex. Never mind about that, my masters: if you want varied instincts +in which to seek the source of the complex by means of the simple, it +is not necessary to search the foliations of the coal-seams and the +successive layers of the rocks, those archives of the prehistoric world; +the present day affords to contemplation an inexhaustible treasury +realizing perhaps everything that can emerge from the limbo of +possibility. In what will soon be half a century of study, I have caught +but a tiny glimpse of a very tiny corner of the realm of instinct; and +the harvest gathered overwhelms me with its variety: I do not yet know +two species of predatory Wasps whose methods are exactly the same. + +One gives a single stroke of the dagger, a second two, a third three, a +fourth nine or ten. One stabs here and the other there; and neither +is imitated by the next, who attacks elsewhere. This one injures the +cephalic centres and produces death; that one respects them and produces +paralysis. Some squeeze the cervical ganglia to obtain a temporary +torpor; others know nothing of the effects of compressing the brain. A +few make the prey disgorge, lest its honey should poison the offspring; +the majority do not resort to preventive manipulations. Here are some +that first disarm the foe, who carries poisoned daggers; yonder are +others and more numerous, who have no precautions to take before +murdering the unarmed prey. In the preliminary struggle, I know some who +grab their victims by the neck, by the rostrum, by the antennae, by the +caudal threads; I know some who throw them on their backs, some who +lift them breast to breast, some who operate on them in the vertical +position, some who attack them lengthwise and crosswise, some who climb +on their backs or on their abdomens, some who press on their backs to +force out a pectoral fissure, some who open their desperately contracted +coil, using the tip of the abdomen as a wedge. And so I could go on +indefinitely: every method of fencing is employed. What could I not also +say about the egg, slung pendulum-fashion by a thread from the ceiling, +when the live provisions are wriggling underneath; laid on a scanty +mouthful, a solitary opening dish, when the dead prey requires renewing +from day to-day; entrusted to the last joint stored away, when the +victuals are paralysed; fixed at a precise spot, entailing the least +danger to the consumer and the game, when the corpulent prey has to be +devoured with a special art that warrants its freshness! + +Well, how can this multitude of varied instincts teach us anything +about gradual transformation? Will the one and only dagger-thrust of the +Cerceris and the Scolia take us to the two thrusts of the Calicurgus, to +the three thrusts of the Sphex, to the manifold thrust of the Ammophila? +Yes, if we consider only numerical progression. One and one are two; two +and one are three: so run the figures. But is this what we want to +know? What has arithmetic to do with the case? Is not the whole problem +subordinate to a condition that cannot be translated into cyphers? As +the prey changes, the anatomy changes; and the surgeon always operates +with a complete understanding of his subject. The single dagger-thrust +is administered to ganglia collected into a common cluster; the manifold +thrusts are distributed over the scattered ganglia; of the two thrusts +of the Tarantula-huntress, one disarms and the other paralyses. And so +with the others: that is to say, the instinct is directed each time by +the secrets of the nervous organism. There is a perfect harmony between +the operation and the patient's anatomy. + +The single stroke of the Scolia is no less wonderful than the repeated +strokes of the Ammophila. Each has her appointed game and each slays it +by a method as rational as any that our own science could invent. In +the presence of this consummate knowledge, which leaves us utterly +confounded, what a poor argument is that of 1 + 1 = 2! And what is that +progress by units to us? The universe is mirrored in a drop of water; +universal logic flashes into sight in a single sting. + +Besides, push on the pitiful argument. One leads to two, two lead to +three. Granted without dispute. And then? We will accept the Scolia +as the pioneer, the foundress of the first principles of the art. The +simplicity of her method justifies our supposition. She learns her +trade in some way or other, by accident; she knows supremely well how +to paralyse her Cetonia-grub with a single dagger-thrust driven into +the thorax. One day, through some fortuitous circumstance, or rather +by mistake, she takes it into her head to strike two blows. As one is +enough for the Cetonia, the repetition was of no value unless there was +a change of prey. What was the new victim submitted to the butcher's +knife? Apparently, a large Spider, since the Tarantula and the Garden +Spider call for two thrusts. And the prentice Scolia, who used at first +to sting under the throat, had the skill, at her first attempt, to begin +by disarming her adversary and then to go quite low down, almost to the +end of the thorax, to strike the vital point. I am utterly incredulous +as to her success. I see her eaten up if her lancet swerves and hits the +wrong spot. Let us look impossibility boldly in the face and admit that +she succeeds. I then see the offspring, which have no recollection of +the fortunate event save through the belly--and then we are postulating +that the digestion of the carnivorous larva leaves a trace in the memory +of the honey-sipping insect--I see the offspring, I say, obliged to wait +at long intervals for that inspired double thrust and obliged to succeed +each time under pain of death for them and their descendants. To accept +this host of impossibilities exceeds all my faculties of belief. One +leads to two, no doubt; the Ssingle blow of the predatory Wasp will +never lead to the blow twice delivered. + +In order to live, we all require the conditions that enable us to live: +this is a truth worthy of the famous axioms of La Palice. (Jacques de +Chabannes, Seigneur de La Palice [circa 1470-1525]), was a French captain +killed at the battle of Pavia. His soldiers made up in his honour a +ballad, two lines of which, translated, run: + +Fifteen minutes before he died, He was still alive. + +(Hence the French expression, une verite de La Palice, meaning an obvious +truth.--Translator's Note.) + +The predatory insects live by their talent. If they do not possess it to +perfection, their race is lost. Hidden in the murk of the past ages, the +argument based upon the non-existence of fossil instinct is no better +able than the others to withstand the light of living realities; it +crumbles under the stroke of fate; it vanishes before a La Palice +platitude. + + + + +CHAPTER 12. THE HALICTI: A PARASITE. + +Do you know the Halicti? Perhaps not. There is no great harm done: it is +quite possible to enjoy the few sweets of existence without knowing +the Halicti. Nevertheless, when questioned persistently, these humble +creatures with no history can tell us some very singular things; and +their acquaintance is not to be disdained if we would enlarge our ideas +upon the bewildering swarm of this world. Since we have nothing better +to do, let us look into the Halicti. They are worth the trouble. + +How shall we recognize them? They are manufacturers of honey, generally +longer and slighter than the Bee of our hives. They constitute a +numerous group that varies greatly in size and colouring. Some there are +that exceed the dimensions of the Common Wasp; others might be compared +with the House-fly, or are even smaller. In the midst of this variety, +which is the despair of the novice, one characteristic remains +invariable. Every Halictus carries the clearly-written certificate of +her guild. + +Examine the last ring, at the tip of the abdomen, on the dorsal surface. +If your capture be an Halictus, there will be here a smooth and shiny +line, a narrow groove along which the sting slides up and down when the +insect is on the defensive. This slide for the unsheathed weapon denotes +some member of the Halictus tribe, without distinction of size or +colour. No elsewhere, in the sting-bearing order, is this original sort +of groove in use. It is the distinctive mark, the emblem of the family. + +Three Halicti will appear before you in this biographical fragment. Two +of them are my neighbours, my familiars, who rarely fail to settle each +year in the best parts of the enclosure. They occupied the ground before +I did; and I should not dream of evicting them, persuaded as I am that +they will well repay my indulgence. Their proximity, which allows me to +visit them daily at my leisure, is a piece of good luck. Let us profit +by it. + +At the head of my three subjects is the Zebra Halictus (H. zebrus, +WALCK.), which is beautifully belted around her long abdomen with +alternate black and pale-russet scarves. Her slender shape, her size, +which equals that of the Common Wasp, her simple and pretty dress, +combine to make her the chief representative of the genus here. + +She establishes her galleries in firm soil, where there is no danger +of landslips which would interfere with the work at nesting-time. In my +garden, the well-levelled paths, made of a mixture of tiny pebbles +and red clayey earth, suits her to perfection. Every spring she takes +possession of it, never alone, but in gangs whose number varies greatly, +amounting sometimes to as many as a hundred. In this way she founds what +may be described as small townships, each clearly marked out and distant +from the other, in which the joint possession of the site in no way +entails joint work. + +Each has her home, an inviolable manor which none but the owner has +the right to enter. A sound buffeting would soon call to order any +adventuress who dared to make her way into another's dwelling. No such +indiscretion is suffered among the Halicti. Let each keep to her own +place and to herself and perfect peace will reign in this new-formed +society, made up of neighbours and not of fellow-workers. + +Operations begin in April, most unobtrusively, the only sign of the +underground works being the little mounds of fresh earth. There is no +animation in the building-yards. The labourers show themselves very +seldom, so busy are they at the bottom of their pits. At moments, here +and there, the summit of a tiny mole-hill begins to totter and tumbles +down the slopes of the cone: it is a worker coming up with her armful +of rubbish and shooting it outside, without showing herself in the open. +Nothing more for the moment. + +There is one precaution to be taken: the villages must be protected +against the passers-by, who might inadvertently trample them under foot. +I surround each of them with a palisade of reed-stumps. In the centre +I plant a danger-signal, a post with a paper flag. The sections of the +paths thus marked are forbidden ground; none of the household will walk +upon them. + +May arrives, gay with flowers and sunshine. The navvies of April have +turned themselves into harvesters. At every moment I see them settling, +all befloured with yellow, atop of the mole-hills now turned into +craters. Let us first look into the question of the house. The +arrangement of the home will give us some useful information. A spade +and a three-pronged fork place the insect's crypts before our eyes. + +A shaft as nearly vertical as possible, straight or winding according to +the exigencies of a soil rich in flinty remains, descends to a depth of +between eight and twelve inches. As it is merely a passage in which the +only thing necessary is that the Halictus should find an easy support in +coming and going, this long entrance-hall is rough and uneven. A regular +shape and a polished surface would be out of place here. These artistic +refinements are reserved for the apartments of her young. All that the +Halictus mother asks is that the passage should be easy to go up and +down, to ascend or descend in a hurry. And so she leaves it rugged. Its +width is about that of a thick lead-pencil. + +Arranged one by one, horizontally and at different heights, the cells +occupy the basement of the house. They are oval cavities, three-quarters +of an inch long, dug out of the clay mass. They end in a short +bottle-neck that widens into a graceful mouth. They look like tiny +vaccine-phials laid on their sides. All of them open into the passage. + +The inside of these little cells has the gloss and polish of a stucco +which our most experienced plasterers might envy. It is diapered with +faint longitudinal, diamond-shaped marks. These are the traces of the +polishing-tool that has given the last finish to the work. What can this +polisher be? None other than the tongue, that is obvious. The Halictus +has made a trowel of her tongue and licked the wall daintily and +methodically in order to polish it. + +This final glazing, so exquisite in its perfection, is preceded by a +trimming-process. In the cells that are not yet stocked with provisions, +the walls are dotted with tiny dents like those in a thimble. Here we +recognize the work of the mandibles, which squeeze the clay with their +tips, compress it and purge it of any grains of sand. The result is a +milled surface whereon the polished layer will find a solid adhesive +base. This layer is obtained with a fine clay, very carefully selected +by the insect, purified, softened and then applied atom by atom, after +which the trowel of the tongue steps in, diapering and polishing, while +saliva, disgorged as needed, gives pliancy to the paste and finally +dries into a waterproof varnish. + +The humidity of the subsoil, at the time of the spring showers, would +reduce the little earthen alcove to a sort of pap. The coating of saliva +is an excellent preservative against this danger. It is so delicate +that we suspect rather than see it; but its efficacy is none the less +evident. I fill a cell with water. The liquid remains in it quite well, +without any trace of infiltration. + +The tiny pitcher looks as if it were varnished with galenite. The +impermeability which the potter obtains by the brutal infusion of his +mineral ingredients the Halictus achieves with the soft polisher of her +tongue moistened with saliva. Thus protected, the larva will enjoy all +the advantages of a dry berth, even in rain-soaked ground. + +Should the wish seize us, it is easy to detach the waterproof film, at +least in shreds. Take the little shapeless lump in which a cell has been +excavated and put it in sufficient water to cover the bottom of it. The +whole earthy mass will soon be soaked and reduced to a mud which we are +able to sweep with the point of a hair-pencil. Let us have patience and +do our sweeping gently; and we shall be able to separate from the main +body the fragments of a sort of extremely fine satin. This transparent, +colourless material is the upholstery that keeps out the wet. The +Spider's web, if it formed a stuff and not a net, is the only thing that +could be compared with it. + +The Halictus' nurseries are, as we see, structures that take much time +in the making. The insect first digs in the clayey earth a recess with +an oval curve to it. It has its mandibles for a pick-axe and its tarsi, +armed with tiny claws, for rakes. Rough though it be, this early work +presents difficulties, for the Bee has to do her excavating in a narrow +gully, where there is only just room for her to pass. + +The rubbish soon becomes cumbersome. The insect collects it and then, +moving backwards, with its fore-legs closed over the load, it hoists it +up through the shaft and flings it outside, upon the mole-hill, which +rises by so much above the threshold of the burrow. Next come the dainty +finishing-touches: the milling of the wall, the application of a glaze +of better-quality clay, the assiduous polishing with the long-suffering +tongue, the waterproof coating and the jarlike mouth, a masterpiece of +pottery in which the stopping-plug will be fixed when the time comes +for locking the door of the room. And all this has to be done with +mathematical precision. + +No, because of this perfection, the grubs' chambers could never be +work done casually from day to day, as the ripe eggs descend from the +ovaries. They are prepared long beforehand, during the bad weather, +at the end of March and in April, when flowers are scarce and the +temperature subject to sudden changes. This thankless period, often +cold, liable to hail-storms, is spent in making ready the home. Alone +at the bottom of her shaft, which she rarely leaves, the mother works at +her children's apartments, lavishing upon them those finishing-touches +which leisure allows. They are completed, or very nearly, when May comes +with the radiant sunshine and wealth of flowers. + +We see the evidence of these long preparations in the burrows +themselves, if we inspect them before the provisions are brought. All of +them show us cells, about a dozen in number, quite finished, but still +empty. To begin by getting all the huts built is a sensible precaution: +the mother will not have to turn aside from the delicate task of +harvesting and egg-laying in order to perform rough navvy's work. + +Everything is ready by May. The air is balmy; the smiling lawns are +gay with a thousand little flowers, dandelions, rock-roses, tansies +and daisies, among which the harvesting Bee rolls gleefully, covering +herself with pollen. With her crop full of honey and the brushes of her +legs befloured, the Halictus returns to her village. Flying very low, +almost level with the ground, she hesitates, with sudden turns and +bewildered movements. It seems that the weak-sighted insect finds its +way with difficulty among the cottages of its little township. + +Which is its mole-hill among the many others near, all similar in +appearance? It cannot tell exactly save by the sign-board of certain +details known to itself alone. Therefore, still on the wing, tacking +from side to side, it examines the locality. The home is found at last: +the Halictus alights on the threshold of her abode and dives into it +quickly. + +What happens at the bottom of the pit must be the same thing that +happens in the case of the other Wild Bees. The harvester enters a cell +backwards; she first brushes herself and drops her load of pollen; then, +turning round, she disgorges the honey in her crop upon the floury mass. +This done, the unwearied one leaves the burrow and flies away, back to +the flowers. After many journeys, the stack of provisions in the cell is +sufficient. This is the moment to bake the cake. + +The mother kneads her flour, mingles it sparingly with honey. The +mixture is made into a round loaf, the size of a pea. Unlike our own +loaves, this one has the crust inside and the crumb outside. The middle +part of the roll, the ration which will be consumed last, when the grub +has acquired some strength, consists of almost nothing but dry pollen. +The Bee keeps the dainties in her crop for the outside of the loaf, +whence the feeble grub-worm is to take its first mouthfuls. Here it is +all soft crumb, a delicious sandwich with plenty of honey. The little +breakfast-roll is arranged in rings regulated according to the age of +the nurseling: first the syrupy outside and at the very end the dry +inside. Thus it is ordained by the economics of the Halictus. + +An egg bent like a bow is laid upon the sphere. According to the +generally-accepted rule, it now only remains to close the +cabin. Honey-gatherers--Anthophorae, Osmiae, Mason-bees and many +others--usually first collect a sufficient stock of food and then, +having laid the egg, shut up the cell, to which they need pay no more +attention. The Halicti employ a different method. The compartments, each +with its round loaf and its egg--the tenant and his provisions--are not +closed up. As they all open into the common passage of the burrow, the +mother is able, without leaving her other occupations, to inspect them +daily and enquire tenderly into the progress of her family. I imagine, +without possessing any certain proof, that from time to time she +distributes additional provisions to the grubs, for the original loaf +appears to me a very frugal ration compared with that served by the +other Bees. + +Certain hunting Hymenoptera, the Bembex-wasps, for instance, are +accustomed to furnish the provisions in instalments: so that the grub +may have fresh though dead game, they fill the platter each day. The +Halictus mother has not these domestic necessities, as her provisions +keep more easily; but still she might well distribute a second portion +of flour to the larvae, when their appetite attains its height. I can +see nothing else to explain the open doors of the cells during the +feeding-period. + +At last the grubs, close-watched and fed to repletion, have achieved the +requisite degree of fatness; they are on the eve of being transformed +into pupae. Then and not till then the cells are closed: a big clay +stopper is built by the mother into the spreading mouth of the jug. +Henceforth the maternal cares are over. The rest will come of itself. + +Hitherto we have witnessed only the peaceful details of the +housekeeping. Let us go back a little and we shall be witnesses of +rampant brigandage. In May, I visit my most populous village daily, at +about ten o'clock in the morning, when the victualling-operations are in +full swing. Seated on a low chair in the sun, with my back bent and my +arms upon my knees, I watch, without moving, until dinner-time. What +attracts me is a parasite, a trumpery Gnat, the bold despoiler of the +Halictus. + +Has the jade a name? I trust so, without, however, caring to waste +my time in enquiries that can have no interest for the reader. Facts +clearly stated are preferable to the dry minutiae of nomenclature. Let +me content myself with giving a brief description of the culprit. She +is a Dipteron, or Fly, five millimetres long. (.195 inch.--Translator's +Note.) Eyes, dark-red; face, white. Corselet, pearl-grey, with five +rows of fine black dots, which are the roots of stiff bristles pointing +backwards. Greyish belly, pale below. Black legs. + +She abounds in the colony under observation. Crouching in the sun, +near a burrow, she waits. As soon as the Halictus arrives from her +harvesting, her legs yellow with pollen, the Gnat darts forth and +pursues her, keeping behind her in all the turns of her oscillating +flight. At last, the Bee suddenly dives indoors. No less suddenly the +other settles on the mole-hill, quite close to the entrance. Motionless, +with her head turned towards the door of the house, she waits for the +Bee to finish her business. The latter reappears at last and, for a few +seconds, stands on the threshold, with her head and thorax outside the +hole. The Gnat, on her side, does not stir. + +Often, they are face to face, separated by a space no wider than a +finger's breadth. Neither of them shows the least excitement. The +Halictus--judging, at least, by her tranquillity--takes no notice of +the parasite lying in wait for her; the parasite, on the other hand, +displays no fear of being punished for her audacity. She remains +imperturbable, she, the dwarf, in the presence of the colossus who could +crush her with one blow. + +In vain I watch anxiously for some sign of apprehension on either side: +nothing in the Halictus points to a knowledge of the danger run by +her family; nor does the Gnat betray any dread of swift retribution. +Plunderer and plundered stare at each other for a moment; and that is +all. + +If she liked, the amiable giantess could rip up with her claw the tiny +bandit who ruins her home; she could crunch her with her mandibles, run +her through with her stiletto. She does nothing of the sort, but leaves +the robber in peace, to sit quite close, motionless, with her red eyes +fixed on the threshold of the house. Why this fatuous clemency? + +The Bee flies off. Forthwith, the Gnat walks in, with no more ceremony +than if she were entering her own place. She now chooses among the +victualled cells at her ease, for they are all open, as I have said; +she leisurely deposits her eggs. No one will disturb her until the Bee's +return. To flour one's legs with pollen, to distend one's crop with +syrup is a task that takes long a-doing; and the intruder, therefore, +has time and to spare wherein to commit her felony. Moreover, her +chronometer is well-regulated and gives the exact measure of the Bee's +length of absence. When the Halictus comes back from the fields, the +Gnat has decamped. In some favourable spot, not far from the burrow, she +awaits the opportunity for a fresh misdeed. + +What would happen if a parasite were surprised at her work by the Bee? +Nothing serious. I see them, greatly daring, follow the Halictus right +into the cave and remain there for some time while the mixture of pollen +and honey is being prepared. Unable to make use of the paste so long as +the harvester is kneading it, they go back to the open air and wait +on the threshold for the Bee to come out. They return to the sunlight, +calmly, with unhurried steps: a clear proof that nothing untoward has +occurred in the depths where the Halictus works. + +A tap on the Gnat's neck, if she become too enterprising in the +neighbourhood of the cake: that is all that the lady of the house seems +to allow herself, to drive away the intruder. There is no serious +affray between the robber and the robbed. This is apparent from the +self-possessed manner and undamaged condition of the dwarf who returns +from visiting the giantess engaged down in the burrow. + +The Bee, when she comes home, whether laden with provisions or not, +hesitates, as I have said, for a while; in a series of rapid zigzags, +she moves backwards, forwards and from side to side, at a short distance +from the ground. This intricate flight at first suggests the idea +that she is trying to lead her persecutress astray by means of an +inextricable tangle of marches and countermarches. That would certainly +be a prudent move on the Bee's part; but so much wisdom appears to be +denied her. + +It is not the enemy that is disturbing her, but rather the difficulty of +finding her own house amid the confusion of the mole-hills, encroaching +one upon the other, and all the alleys of the little township, which, +owing to landslips of fresh rubbish, alter in appearance from one day to +the next. Her hesitation is manifest, for she often blunders and alights +at the entrance to a burrow that is not hers. The mistake is at once +perceived from the slight indications of the doorway. + +The search is resumed with the same see-sawing flights, mingled with +sudden excursions to a distance. At last, the burrow is recognized. +The Halictus dives into it with a rush; but, however prompt her +disappearance underground, the Gnat is there, perched on the threshold +with her eyes turned to the entrance, waiting for the Bee to come out, +so that she may visit the honey-jars in her turn. + +When the owner of the house ascends, the other draws back a little, just +enough to leave a free passage and no more. Why should she put herself +out? the meeting is so peaceful that, short of further information, one +would not suspect that a destroyer and destroyed were face to face. Far +from being intimidated by the sudden arrival of the Halictus, the Gnat +pays hardly any attention; and, in the same way, the Halictus takes no +notice of her persecutress, unless the bandit pursue her and worry her +on the wing. Then, with a sudden bend, the Bee makes off. + +Even so do Philanthus apivorus (The Bee-hunting Wasp. Cf. "Social Life +in the Insect World": chapter 13.--Translator's Note.) and the other +game-hunters behave when the Tachina is at their heels seeking the +chance to lay her egg on the morsel about to be stored away. Without +jostling the parasite which they find hanging around the burrow, they +go indoors quite peaceably; but, on the wing, perceiving her after them, +they dart off wildly. The Tachina, however, dares not go down to the +cells where the huntress stacks her provisions; she prudently waits at +the door for the Philanthus to arrive. The crime, the laying of the +egg, is committed at the very moment when the victim is about to vanish +underground. + +The troubles of the parasite of the Halictus are of quite another +kind. The homing Bee has her honey in her crop and her pollen on her +leg-brushes: the first is inaccessible to the thief; the second is +powdery and would give no resting-place to the egg. Besides, there is +not enough of it yet: to collect the wherewithal for that round loaf of +hers, the Bee will have to make repeated journeys. When the necessary +amount is obtained, she will knead it with the tip of her mandibles +and shape it with her feet into a little ball. The Gnat's egg, were it +present among the materials, would certainly be in danger during this +manipulation. + +The alien egg, therefore, must be laid on the finished bread; and, as +the preparation takes place underground, the parasite is needs obliged +to go down to the Halictus. With inconceivable daring, she does go +down, even when the Bee is there. Whether through cowardice or silly +indulgence, the dispossessed insect lets the other have its way. + +The object of the Gnat, with her tenacious lying-in-wait and her +reckless burglaries, is not to feed herself at the harvester's expense: +she could get her living out of the flowers with much less trouble +than her thieving trade involves. The most, I think, that she can allow +herself to do in the Halictus' cellars is to take one morsel just to +ascertain the quality of the victuals. Her great, her sole business is +to settle her family. The stolen goods are not for herself, but for her +offspring. + +Let us dig up the pollen-loaves. We shall find them most often crumbled +with no regard to economy, simply frittered away. We shall see two or +three maggots, with pointed mouths, moving in the yellow flour scattered +over the floor of the cell. These are the Gnat's progeny. With them +we sometimes find the lawful owner, the grub-worm of the Halictus, but +stunted and emaciated with fasting. His gluttonous companions, without +otherwise molesting him, deprive him of the best of everything. The +wretched starveling dwindles, shrivels up and soon disappears from view. +His corpse, a mere atom, blended with the remaining provisions, supplies +the maggots with one mouthful the more. + +And what does the Halictus mother do in this disaster? She is free to +visit her grubs at any moment; she has but to put her head into the +passage of the house: she cannot fail to be apprised of their distress. +The squandered loaf, the swarming mass of vermin tell their own tale. +Why does she not take the intruders by the skin of the abdomen? To grind +them to powder with her mandibles, to fling them out of doors were +the business of a second. And the foolish creature never thinks of it, +leaves the ravagers in peace! + +She does worse. When the time of the nymphosis comes, the Halictus +mother goes to the cells rifled by the parasite and closes them with an +earthen plug as carefully as she does the rest. This final barricade, an +excellent precaution when the cot is occupied by an Halictus in course +of metamorphosis, becomes the height of absurdity when the Gnat +has passed that way. Instinct does not hesitate in the face of this +ineptitude: it seals up emptiness. I say, emptiness, because the crafty +maggot hastens to decamp the instant that the victuals are consumed, as +though it foresaw an insuperable obstacle for the coming Fly: it quits +the cell before the Bee closes it. + +To rascally guile the parasite adds prudence. All, until there is none +of them left, abandon the clay homes which would be their undoing once +the entrance was plugged up. The earthen niche, so grateful to the +tender skin, thanks to its polished coating, so free from humidity, +thanks to its waterproof glaze, ought, one would think, to make an +excellent waiting-place. The maggots will have none of it. Lest they +should find themselves walled in when they become frail Gnats, they go +away and disperse in the neighbourhood of the ascending shaft. + +My digging operations, in fact, always reveal the pupae outside the +cells, never inside. I find them enshrined, one by one, in the body +of the clayey earth, in a narrow recess which the emigrant worm has +contrived to make for itself. Next spring, when the hour comes for +leaving, the adult insect has but to creep through the rubbish, which is +easy work. + +Another and no less imperative reason compels this change of abode on +the parasite's part. In July, a second generation of the Halictus is +procreated. The Gnat, reduced on her side to a single brood, remains +in the pupa state and awaits the spring of the following year before +effecting her transformation. The honey-gather resumes her work in her +native village; she avails herself of the pits and cells constructed in +the spring, saving no little time thereby. The whole elaborate structure +has remained in good condition. It needs but a few repairs to make the +old house habitable. + +Now what would happen if the Bee, so scrupulous in matters of +cleanliness, were to find a pupa in the cell which she is sweeping? She +would treat the cumbersome object as she would a piece of old plaster. +It would be no more to her than any other refuse, a bit of gravel, +which, seized with the mandibles, crushed perhaps, would be sent to join +the rubbish-heap outside. Once removed from the soil and exposed to the +inclemencies of the weather, the pupa would inevitably perish. + +I admire this intelligent foresight of the maggot, which forgoes the +comfort of the moment for the security of the future. Two dangers +threaten it: to be immured in a casket whence the Fly can never issue; +or else to die out of doors, in the unkindly air, when the Bee sweeps +out the restored cells. To avoid this twofold peril, it decamps before +the door is closed, before the July Halictus sets her house in order. + +Let us now see what comes of the parasite's intrusion. In the course +of June, when peace is established in the Halictus' home, I dig up +my largest village, comprising some fifty burrows in all. None of the +sorrows of this underworld shall escape me. There are four of us +engaged in sifting the excavated earth through our fingers. What one +has examined another takes up and examines; and then another and another +yet. The returns are heartrending. We do not succeed in finding one +single nymph of the Halictus. The whole of the populous city has +perished; and its place has been taken by the Gnat. There is a glut +of that individual's pupae. I collect them in order to trace their +evolution. + +The year runs its course; and the little russet kegs, into which the +original maggots have hardened and contracted, remain stationary. They +are seeds endowed with latent life. The heats of July do not rouse them +from their torpor. In that month, the period of the second generation +of the Halictus, there is a sort of truce of God: the parasite rests and +the Bee works in peace. If hostilities were to be resumed straight +away, as murderous in summer as they were in spring, the progeny of the +Halictus, too cruelly smitten, might possibly disappear altogether. This +lull readjusts the balance. + +In April, when the Zebra Halictus, in search of a good place for her +burrows, roams up and down the garden paths with her oscillating +flight, the parasite, on its side, hastens to hatch. Oh, the precise +and terrible agreement between those two calendars, the calendar of the +persecutor and the persecuted! At the very moment when the Bee comes +out, here is the Gnat: she is ready to begin her deadly starving-process +all over again. + +Were this an isolated case, one's mind would not dwell upon it: an +Halictus more or less in the world makes little difference in the +general balance. But, alas, brigandage in all its forms is the rule in +the eternal conflict of living things! From the lowest to the highest, +every producer is exploited by the unproductive. Man himself, whose +exceptional rank ought to raise him above such baseness, excels in this +ravening lust. He says to himself that business means getting hold of +other people's cash, even as the Gnat says to herself that business +means getting hold of the Halictus' honey. And, to play the brigand +to better purpose, he invents war, the art of killing wholesale and of +doing with glory that which, when done on a smaller scale, leads to the +gallows. + +Shall we never behold the realization of that sublime vision which is +sung on Sundays in the smallest village-church: Gloria in excelsis Deo, +et in terra pax hominibus bonae voluntatis! If war affected humanity +alone, perhaps the future would have peace in store for us, seeing that +generous minds are working for it with might and main; but the scourge +also rages among the lower animals, which in their obstinate way, +will never listen to reason. Once the evil is laid down as a general +condition, it perhaps becomes incurable. Life in the future, it is to be +feared, will be what it is to-day, a perpetual massacre. + +Whereupon, by a desperate effort of the imagination, one pictures to +oneself a giant capable of juggling with the planets. He is irresistible +strength; he is also law and justice. He knows of our battles, our +butcheries, our farm-burnings, our town-burnings, our brutal triumphs; +he knows our explosives, our shells, our torpedo-boats, our ironclads +and all our cunning engines of destruction; he knows as well the +appalling extent of the appetites among all creatures, down to the +very lowest. Well, if that just and mighty one held the earth under his +thumb, would he hesitate whether he ought to crush it? + +He would not hesitate...He would let things take their course. He would +say to himself: + +'The old belief is right; the earth is a rotten apple, gnawed by the +vermin of evil. It is a first crude attempt, a step towards a kindlier +destiny. Let it be: order and justice are waiting at the end.' + + + + +CHAPTER 13. THE HALICTI: THE PORTRESS. + +Leaving our village is no very serious matter when we are children. We +even look on it as a sort of holiday. We are going to see something new, +those magic pictures of our dreams. With age come regrets; and the close +of life is spent in stirring up old memories. Then the beloved village +reappears, in the biograph of the mind, embellished, transfigured by the +glow of those first impressions; and the mental image, superior to the +reality, stands out in amazingly clear relief. The past, the far-off +past, was only yesterday; we see it, we touch it. + +For my part, after three-quarters of a century, I could walk with my +eyes closed straight to the flat stone where I first heard the soft +chiming note of the Midwife Toad; yes, I should find it to a certainty, +if time, which devastates all things, even the homes of Toads, has not +moved it or perhaps left it in ruins. + +I see, on the margin of the brook, the exact position of the alder-trees +whose tangled roots, deep under the water, were a refuge for the +Crayfish. I should say: + +'It is just at the foot of that tree that I had the unutterable bliss of +catching a beauty. She had horns so long...and enormous claws, full of +meat, for I got her just at the right time.' + +I should go without faltering to the ash under whose shade my heart +beat so loudly one sunny spring morning. I had caught sight of a sort of +white, cottony ball among the branches. Peeping from the depths of +the wadding was an anxious little head with a red hood to it. O what +unparalleled luck! It was a Goldfinch, sitting on her eggs. + +Compared with a find like this, lesser events do not count. Let us leave +them. In any case, they pale before the memory of the paternal garden, +a tiny hanging garden of some thirty paces by ten, situated right at +the top of the village. The only spot that overlooks it is a little +esplanade on which stands the old castle (The Chateau de Saint-Leons +standing just outside and above the village of Saint-Leons, where the +author was born in 1823. Cf. "The Life of the Fly": chapters 6 and +7.--Translator's Note.) with the four turrets that have now become +dovecotes. A steep path takes you up to this open space. From my house +on, it is more like a precipice than a slope. Gardens buttressed by +walls are staged in terraces on the sides of the funnel-shaped valley. +Ours is the highest; it is also the smallest. + +There are no trees. Even a solitary apple-tree would crowd it. There +is a patch of cabbages, with a border of sorrel, a patch of turnips and +another of lettuces. That is all we have in the way of garden-stuff; +there is no room for more. Against the upper supporting-wall, facing due +south, is a vine-arbour which, at intervals, when the sun is generous, +provides half a basketful of white muscatel grapes. These are a luxury +of our own, greatly envied by the neighbours, for the vine is unknown +outside this corner, the warmest in the village. + +A hedge of currant-bushes, the only safeguard against a terrible fall, +forms a parapet above the next terrace. When our parents' watchful eyes +are off us, we lie flat on our stomachs, my brother and I, and look into +the abyss at the foot of the wall bulging under the thrust of the land. +It is the garden of monsieur le notaire. + +There are beds with box-borders in that garden; there are pear-trees +reputed to give pears, real pears, more or less good to eat when +they have ripened on the straw all through the late autumn. In our +imagination, it is a spot of perpetual delight, a paradise, but a +paradise seen the wrong way up: instead of contemplating it from below, +we gaze at it from above. How happy they must be with so much space and +all those pears! + +We look at the hives, around which the hovering Bees make a sort of +russet smoke. They stand under the shelter of a great hazel. The tree +has sprung up all of itself in a fissure of the wall, almost on the +level of our currant-bushes. While it spreads its mighty branches over +the notary's hives, its roots, at least, are on our land. It belongs to +us. The trouble is to gather the nuts. + +I creep along astride the strong branches projecting horizontally into +space. If I slip or if the support breaks, I shall come to grief in the +midst of the angry Bees. I do not slip and the support does not break. +With the bent switch which my brother hands me, I bring the finest +clusters within my reach. I soon fill my pockets. Moving backwards, +still straddling my branch, I recover terra firma. O wondrous days of +litheness and assurance, when, for a few filberts, on a perilous perch +we braved the abyss! + +Enough. These reminiscences, so dear to my dreams, do not interest the +reader. Why stir up more of them? I am content to have brought this fact +into prominence: the first glimmers of light penetrating into the dark +chambers of the mind leave an indelible impression, which the years make +fresher instead of dimmer. + +Obscured by everyday worries, the present is much less familiar to us, +in its petty details, than the past, with childhood's glow upon it. I +see plainly in my memory what my prentice eyes saw; and I should never +succeed in reproducing with the same accuracy what I saw last week. I +know my village thoroughly, though I quitted it so long ago; and I know +hardly anything of the towns to which the vicissitudes of life have +brought me. An exquisitely sweet link binds us to our native soil; we +are like the plant that has to be torn away from the spot where it put +out its first roots. Poor though it be, I should love to see my own +village again; I should like to leave my bones there. + +Does the insect in its turn receive a lasting impression of its earliest +visions? Has it pleasant memories of its first surroundings? We will +not speak of the majority, a world of wandering gipsies who establish +themselves anywhere provided that certain conditions be fulfilled; but +the others, the settlers, living in groups: do they recall their native +village? Have they, like ourselves, a special affection for the place +which saw their birth? + +Yes, indeed they have: they remember, they recognize the maternal abode, +they come back to it, they restore it, they colonize it anew. Among many +other instances, let us quote that of the Zebra Halictus. She will show +us a splendid example of love for one's birthplace translating itself +into deeds. + +The Halictus' spring family acquire the adult form in a couple of months +or so; they leave the cells about the end of June. What goes on inside +these neophytes as they cross the threshold of the burrow for the +first time? Something, apparently, that may be compared with our own +impressions of childhood. An exact and indelible image is stamped on +their virgin memories. Despite the years, I still see the stone +whence came the resonant notes of the little Toads, the parapet of +currant-bushes, the notary's garden of Eden. These trifles make the best +part of my life. The Halictus sees in the same way the blade of grass +whereon she rested in her first flight, the bit of gravel which her claw +touched in her first climb to the top of the shaft. She knows her +native abode by heart just as I know my village. The locality has become +familiar to her in one glad, sunny morning. + +She flies off, seeks refreshment on the flowers near at hand and visits +the fields where the coming harvests will be gathered. The distance does +not lead her astray, so faithful are her impressions of her first trip; +she finds the encampment of her tribe; among the burrows of the village, +so numerous and so closely resembling one another, she knows her own. +It is the house where she was born, the beloved house with its +unforgettable memories. + +But, on returning home, the Halictus is not the only mistress of the +house. The dwelling dug by the solitary Bee in early spring remains, +when summer comes, the joint inheritance of the members of the family. +There are ten cells, or thereabouts, underground. Now from these cells +there have issued none but females. This is the rule among the three +species of Halicti that concern us now and probably also among many +others, if not all. They have two generations in each year. The spring +one consists of females only; the summer one comprises both males +and females, in almost equal numbers. We shall return to this curious +subject in our next chapter. + +The household, therefore, if not reduced by accidents, above all if not +starved by the usurping Gnat, would consist of half-a-score of sisters, +none but sisters, all equally industrious and all capable of procreating +without a nuptial partner. On the other hand, the maternal dwelling is +no hovel; far from it: the entrance-gallery, the principal room of the +house, will serve quite well, after a few odds and ends of refuse have +been swept away. This will be so much gained in time, ever precious +to the Bee. The cells at the bottom, the clay cabins, are also nearly +intact. To make use of them, it will be enough for the Halictus to +polish up the stucco with her tongue. + +Well, which of the survivors, all equally entitled to the succession, +will inherit the house? There are six of them, seven, or more, according +to the chances of mortality. To whose share will the maternal dwelling +fall? + +There is no quarrel between the interested parties. The mansion is +recognized as common property without dispute. The sisters come and go +peacefully through the same door, attend to their business, pass and +let the others pass. Down at the bottom of the pit, each has her little +demesne, her group of cells dug at the cost of fresh toil, when the old +ones, now insufficient in number, are occupied. In these recesses, +which are private estates, each mother works by herself, jealous of her +property and of her privacy. Every elsewhere, traffic is free to all. + +The exits and entrances in the working fortress provide a spectacle +of the highest interest. A harvester arrives from the fields, the +feather-brushes of her legs powdered with pollen. If the door be open, +the Bee at once dives underground. To tarry on the threshold would mean +waste of time; and the business is urgent. Sometimes, several appear +upon the scene at almost the same moment. The passage is too narrow for +two, especially when they have to avoid any untimely contact that would +make the floury burden fall to the floor. The nearest to the opening +enters quickly. The others, drawn up on the threshold in order of their +arrival, respectful of one another's rights, await their turn. As soon +as the first disappears, the second follows after her and is herself +swiftly followed by the third and then the others, one by one. + +Sometimes, again, there is a meeting between a Bee about to come out and +a Bee about to go in. Then the latter draws back a little and makes way +for the former. The politeness is reciprocal. I see some who, when on +the point of emerging from the pit, go down again and leave the passage +free for the one who has just arrived. Thanks to this mutual spirit of +accommodation, the business of the house proceeds without impediment. + +Let us keep our eyes open. There is something better than the +well-preserved order of the entrances. When an Halictus appears, +returning from her round of the flowers, we see a sort of trap-door, +which closed the house, suddenly fall and give a free passage. As soon +as the new arrival has entered, the trap rises back into its place, +almost level with the ground, and closes the entrance anew. The same +thing happens when the insects go out. At a request from within, the +trap descends, the door opens and the Bee flies away. The outlet is +closed forthwith. + +What can this valve be which, descending or ascending in the cylinder +of the pit, after the fashion of a piston, opens and closes the house +at each departure and at each arrival? It is an Halictus, who has become +the portress of the establishment. With her large head, she makes an +impassable barrier at the top of the entrance-hall. If any one belonging +to the house wants to go in or out, she 'pulls the cord,' that is to +say, she withdraws to a spot where the gallery becomes wider and leaves +room for two. The other passes. She then at once returns to the +orifice and blocks it with the top of her head. Motionless, ever on the +look-out, she does not leave her post save to drive away importunate +visitors. + +Let us profit by her brief appearances outside to take a look at her. We +recognize in her an Halictus similar to the others, which are now busy +harvesting; but the top of her head is bald and her dress is dingy +and thread-bare. All the nap is gone; and one can hardly make out +the handsome stripes of red and brown which she used to have. These +tattered, work-worn garments make things clear to us. + +This Bee who mounts guard and performs the office of a portress at the +entrance to the burrow is older than the others. She is the foundress of +the establishment, the mother of the actual workers, the grandmother of +the present grubs. In the springtime of her life, three months ago, she +wore herself out in solitary labours. Now that her ovaries are dried +up, she takes a well-earned rest. No, rest is hardly the word. She still +works, she assists the household to the best of her power. Incapable of +being a mother for a second time, she becomes a portress, opens the door +to the members of her family and makes strangers keep their distance. + +The suspicious Kid (In La Fontaine's fable, "Le Loup, la Chevre et le +Chevreau."--Translator's Note.), looking through the chink, said to the +Wolf: + +'Show me a white foot, or I shan't open the door.' + +No less suspicious, the grandmother says to each comer: + +'Show me the yellow foot of an Halictus, or you won't be let in.' + +None is admitted to the dwelling unless she be recognized as a member of +the family. + +See for yourselves. Near the burrow passes an Ant, an unscrupulous +adventuress, who would not be sorry to know the meaning of the honeyed +fragrance that rises from the bottom of the cellar. + +"Be off, or you'll catch it!' says the portress, wagging her neck. + +As a rule the threat suffices. The Ant decamps. Should she insist, +the watcher leaves her sentry-box, flings herself upon the saucy jade, +buffets her and drives her away. The moment the punishment has been +administered, she returns to her post. + +Next comes the turn of a Leaf-cutter (Megachile albocincta, PEREZ), +which, unskilled in the art of burrowing, utilizes, after the manner of +her kin, the old galleries dug by others. Those of the Zebra Halictus +suit her very well, when the terrible Gnat has left them vacant for +lack of heirs. Seeking for a home wherein to stack her robinia-leaf +honey-pots, she often makes a flying inspection of my colonies of +Halicti. A burrow seems to take her fancy; but, before she sets foot on +earth, her buzzing is noticed by the sentry, who suddenly darts out +and makes a few gestures on the threshold of her door. That is all. The +Leaf-cutter has understood. She moves on. + +Sometimes, the Megachile has time to alight and insert her head into +the mouth of the pit. In a moment, the portress is there, comes a +little higher and bars the way. Follows a not very serious contest. +The stranger quickly recognizes the rights of the first occupant and, +without insisting, goes to seek an abode elsewhere. + +An accomplished marauder (Caelioxys caudata, SPIN.), a parasite of the +Megachile, receives a sound drubbing under my eyes. She thought, the +feather-brain, that she was entering the Leaf-Cutter's establishment! +She soon finds out her mistake; she meets the door-keeping Halictus, who +administers a sharp correction. She makes off at full speed. And so with +the others which, through inadvertence or ambition, seek to enter the +burrow. + +The same intolerance exists among the different grandmothers. About the +middle of July, when the animation of the colony is at its height, two +sets of Halicti are easily distinguishable: the young mothers and the +old. The former, much more numerous, brisk of movement and smartly +arrayed, come and go unceasingly from the burrows to the fields and from +the fields to the burrows. The latter, faded and dispirited, wander idly +from hole to hole. They look as though they had lost their way and were +incapable of finding their homes. Who are these vagabonds? I see in them +afflicted ones bereft of a family through the act of the odious Gnat. +Many burrows have been altogether exterminated. At the awakening of +summer, the mother found herself alone. She left her empty house and +went off in search of a dwelling where there were cradles to defend, a +guard to mount. But those fortunate nests already have their overseer, +the foundress, who, jealous of her rights, gives her unemployed +neighbour a cold reception. One sentry is enough; two would merely block +the narrow guard-room. + +I am privileged at times to witness a fight between two grandmothers. +When the tramp in quest of employment appears outside the door, the +lawful occupant does not move from her post, does not withdraw into the +passage, as she would before an Halictus returning from the fields. Far +from making way, she threatens the intruder with her feet and mandibles. +The other retaliates and tries to force her way in notwithstanding. +Blows are exchanged. The fray ends by the defeat of the stranger, who +goes off to pick a quarrel elsewhere. + +These little scenes afford us a glimpse of certain details of the +highest interest in the habits of the Zebra Halictus. The mother who +builds her nest in the spring no longer leaves her home, once her works +are finished. Shut up at the bottom of the burrow, busied with the +thousand cares of housekeeping, or else drowsing, she waits for her +daughters to come out. When, in the summer heats, the life of the +village recommences, having nought to do outside as a harvester, she +stands sentry at the entrance to the hall, so as to let none in save the +workers of the home, her own daughters. She wards off evilly-disposed +visitors. None can enter without the door-keeper's consent. + +There is nothing to tell us that the watcher ever deserts her post. Not +once do I see her leave her house to go and seek some refreshment from +the flowers. Her age and her sedentary occupation, which involves no +great fatigue, perhaps relieve her of the need of nourishment. Perhaps, +also, the young ones returning from their plundering may from time to +time disgorge a drop of the contents of their crops for her benefit. Fed +or unfed, the old one no longer goes out. + +But what she does need is the joys of an active family. Many are +deprived of these. The Gnat's burglary has destroyed the busy household. +The sorely-tried Bees abandon the deserted burrow. It is they who, +ragged and careworn, wander through the village. When they move, their +flight is only a short one; more often they remain motionless. It is +they who, soured in their tempers, attack their fellows and seek to +dislodge them. They grow rarer and more languid from day to day; then +they disappear for good. What has become of them? The little Grey Lizard +had his eye on them: they are easily snapped up. + +Those settled in their own demesne, those who guard the honey-factory +wherein their daughters, the heiresses of the maternal establishment, +are at work, display wonderful vigilance. The more I see of them, the +more I admire them. In the cool hours of the early morning, when the +pollen-flour is not sufficiently ripened by the sun and while the +harvesters are still indoors, I see them at their posts, at the top of +the gallery. Here, motionless, their heads flush with the earth, they +bar the door to all invaders. If I look at them closely, they retreat a +little and, in the shadow, await the indiscreet observer's departure. + +I return when the harvesting is in full swing, between eight o'clock +and twelve. There is now, as the Halicti go in or out, a succession +of prompt withdrawals to open the door and of ascents to close it. The +portress is in the full exercise of her functions. + +In the afternoon, the heat is too great and the workers do not go to the +fields. Retiring to the bottom of the house, they varnish the new cells, +they make the round loaf that is to receive the egg. The grandmother is +still upstairs, stopping the door with her bald head. For her, there +is no siesta during the stifling hours: the safety of the household +requires her to forgo it. + +I come back again at nightfall, or even later. By the light of a +lantern, I again behold the overseer, as zealous and assiduous as in the +day-time. The others are resting, but not she, for fear, apparently, of +nocturnal dangers known to herself alone. Does she nevertheless end +by descending to the quiet of the floor below? It seems probable, so +essential must rest be, after the fatigue of such a vigil! + +It is evident that, guarded in this manner, the burrow is exempt from +calamities similar to those which, too often, depopulate it in May. Let +the Gnat come now, if she dare, to steal the Halictus' loaves! Let her +lie in wait as long as she will! Neither her audacity nor her slyness +will make her escape the lynx eyes of the sentinel, who will put her to +flight with a threatening gesture or, if she persist, crush her with +her nippers. She will not come; and we know the reason: until spring +returns, she is underground in the pupa state. + +But, in her absence, there is no lack, among the Fly rabble, of other +batteners on the toil of their fellow insects. Whatever the job, +whatever the plunder, you will find parasites there. And yet, for all +my daily visits, I never catch one of these in the neighbourhood of the +summer burrows. How cleverly the rascals ply their trade! How well aware +are they of the guard who keeps watch at the Halictus' door! There is +no foul deed possible nowadays; and the result is that no Fly puts in an +appearance and the tribulations of last spring are not repeated. + +The grandmother who, dispensed by age from maternal bothers, mounts +guard at the entrance of the home and watches over the safety of the +family, tells us that in the genesis of the instincts sudden births +occur; she shows us the existence of a spontaneous aptitude which +nothing, either in her own past conduct or in the actions of her +daughters, could have led us to suspect. Timorous in her prime, in the +month of May, when she lived alone in the burrow of her making, she +has become gifted, in her decline, with a superb contempt of danger and +dares in her impotence what she never dared do in her strength. + +Formerly, when her tyrant, the Gnat, entered the house in her presence, +or, more often, stood face to face with her at the entrance, the silly +Bee did not stir, did not even threaten the red-eyed bandit, the dwarf +whose doom she could so easily have sealed. Was it terror on her part? +No, for she attended to her duties with her usual punctiliousness; no, +for the strong do not allow themselves to be thus paralysed by the weak. +It was ignorance of the danger, it was sheer fecklessness. + +And behold, to-day, the ignoramus of three months ago knows the peril, +knows it well, without serving any apprenticeship. Every stranger who +appears is kept at a distance, without distinction of size or race. +If the threatening gesture be not enough, the keeper sallies forth and +flings herself upon the persistent one. Cowardice has developed into +courage. + +How has this change been brought about? I should like to picture the +Halictus gaining wisdom from the misfortunes of the spring and capable +thenceforth of looking out for danger; I would gladly credit her with +having learnt in the stern school of experience the advantages of a +patrol. I must give up the idea. If, by dint of gradual little acts of +progress, the Bee has achieved the glorious invention of a janitress, +how comes it that the fear of thieves is intermittent? It is true that, +being by herself in May, she cannot stand permanently at her door: +the business of the house takes precedence of everything else. But she +ought, at any rate as soon as her offspring are victimized, to know +the parasite and give chase when, at every moment, she finds her almost +under her feet and even in her house. Yet she pays no attention to her. + +The bitter experience of her ancestors, therefore, has bequeathed +nothing to her of a nature to alter her placid character; nor have her +own tribulations aught to do with the sudden awakening of her vigilance +in July. Like ourselves, animals have their joys and their sorrows. +They eagerly make the most of the former; they fret but little about the +latter, which, when all is said, is the best way of achieving a purely +animal enjoyment of life. To mitigate these troubles and protect the +progeny there is the inspiration of instinct, which is able without the +counsels of experience to give the Halicti a portress. + +When the victualling is finished, when the Halicti no longer sally forth +on harvesting intent nor return all befloured with their spoils, the old +Bee is still at her post, vigilant as ever. The final preparations for +the brood are made below; the cells are closed. The door will be kept +until everything is finished. Then grandmother and mothers leave the +house. Exhausted by the performance of their duty, they go, somewhere or +other, to die. + +In September appears the second generation, comprising both males and +females. I find both sexes wassailing on the flowers, especially the +Compositae, the centauries and thistles. They are not harvesting now: +they are refreshing themselves, holding high holiday, teasing one +another. It is the wedding-time. Yet another fortnight and the males +will disappear, henceforth useless. The part of the idlers is played. +Only the industrious ones remain, the impregnated females, who go +through the winter and set to work in April. + +I do not know their exact haunt during the inclement season. I expected +them to return to their native burrow, an excellent dwelling for the +winter, one would think. Excavations made in January showed me my +mistake. The old homes are empty, are falling to pieces owing to the +prolonged effect of the rains. The Zebra Halictus has something better +than these muddy hovels: she has snug corners in the stone-heaps, +hiding-places in the sunny walls and many other convenient habitations. +And so the natives of a village become scattered far and wide. + +In April, the scattered ones reassemble from all directions. On the +well-flattened garden-paths a choice is made of the site for their +common labours. Operations soon begin. Close to the first who bores +her shaft there is soon a second one busy with hers; a third arrives, +followed by another and others yet, until the little mounds often touch +one another, while at times they number as many as fifty on a surface of +less than a square yard. + +One would be inclined, at first sight, to say that these groups are +accounted for by the insect's recollection of its birthplace, by the +fact that the villagers, after dispersing during the winter, return to +their hamlet. But it is not thus that things happen: the Halictus scorns +to-day the place that once suited her. I never see her occupy the same +patch of ground for two years in succession. Each spring she needs new +quarters. And there are plenty of them. + +Can this mustering of the Halicti be due to a wish to resume the old +intercourse with their friends and relations? Do the natives of the same +burrow, of the same hamlet, recognize one another? Are they inclined to +do their work among themselves rather than in the company of strangers? +There is nothing to prove it, nor is there anything to disprove it. +Either for this reason or for others, the Halictus likes to keep with +her neighbours. + +This propensity is pretty frequent among peace-lovers, who, needing +little nourishment, have no cause to fear competition. The others, the +big eaters, take possession of estates, of hunting-grounds from which +their fellows are excluded. Ask a Wolf his opinion of a brother Wolf +poaching on his preserves. Man himself, the chief of consumers, makes +for himself frontiers armed with artillery; he sets up posts at the foot +of which one says to the other: + +'Here's my side, there's yours. That's enough: now we'll pepper each +other.' + +And the rattle of the latest explosives ends the colloquy. + +Happy are the peace-lovers. What do they gain by their mustering? With +them it is not a defensive system, a concerted effort to ward off the +common foe. The Halictus does not care about her neighbour's affairs. +She does not visit another's burrow; she does not allow others to +visit hers. She has her tribulations, which she endures alone; she is +indifferent to the tribulations of her kind. She stands aloof from the +strife of her fellows. Let each mind her own business and leave things +at that. + +But company has its attractions. He lives twice who watches the life of +others. Individual activity gains by the sight of the general activity; +the animation of each one derives fresh warmth from the fire of the +universal animation. To see one's neighbours at work stimulates one's +rivalry. And work is the great delight, the real satisfaction that gives +some value to life. The Halictus knows this well and assembles in her +numbers that she may work all the better. + +Sometimes she assembles in such multitudes and over such extents of +ground as to suggest our own colossal swarms. Babylon and Memphis, Rome +and Carthage, London and Paris, those frantic hives, occur to our mind +if we can manage to forget comparative dimensions and see a Cyclopean +pile in a pinch of earth. + +It was in February. The almond-tree was in blossom. A sudden rush of +sap had given the tree new life; its boughs, all black and desolate, +seemingly dead, were becoming a glorious dome of snowy satin. I have +always loved this magic of the awakening spring, this smile of the first +flowers against the gloomy bareness of the bark. + +And so I was walking across the fields, gazing at the almond-trees' +carnival. Others were before me. An Osmia in a black velvet bodice and +a red woollen skirt, the Horned Osmia, was visiting the flowers, dipping +into each pink eye in search of a honeyed tear. A very small and very +modestly-dressed Halictus, much busier and in far greater numbers, was +flitting silently from blossom to blossom. Official science calls her +Halictus malachurus, K. The pretty little Bee's godfather strikes me as +ill-inspired. What has malachurus, calling attention to the softness +of the rump, to do in this connection? The name of Early Halictus would +better describe the almond-tree's little visitor. + +None of the melliferous clan, in my neighbourhood at least, is stirring +as early as she is. She digs her burrows in February, an inclement +month, subject to sudden returns of frost. When none as yet, even among +her near kinswomen, dares to sally forth from winter-quarters, she +pluckily goes to work, shine the sun ever so little. Like the Zebra +Halictus, she has two generations a year, one in spring and one in +summer; like her, too, she settles by preference in the hard ruts of the +country roads. + +Her mole-hills, those humble mounds any two of which would go +easily into a Hen's egg, rise innumerous in my path, the path by the +almond-trees which is the happy hunting-ground of my curiosity to-day. +This path is a ribbon of road three paces wide, worn into ruts by the +Mule's hoofs and the wheels of the farm-carts. A coppice of holm-oaks +shelters it from the north wind. In this Eden with its well-caked soil, +its warmth and quiet, the little Halictus has multiplied her mole-hills +to such a degree that I cannot take a step without crushing some of +them. The accident is not serious: the miner, safe underground, will +be able to scramble up the crumbling sides of the mine and repair the +threshold of the trampled home. + +I make a point of measuring the density of the population. I count +from forty to sixty mole-hills on a surface of one square yard. The +encampment is three paces wide and stretches over nearly three-quarters +of a mile. How many Halicti are there in this Babylon? I do not venture +to make the calculation. + +Speaking of the Zebra Halictus, I used the words hamlet, village, +township; and the expressions were appropriate. Here the term city +hardly meets the case. And what reason can we allege for these +innumerable clusters? I can see but one: the charm of living together, +which is the origin of society. Like mingles with like, without the +rendering of any mutual service; and this is enough to summon the Early +Halictus to the same way-side, even as the Herring and the Sardine +assemble in the same waters. + + + + +CHAPTER 14. THE HALICTI: PARTHENOGENESIS. + +The Halictus opens up another question, connected with one of life's +obscurest problems. Let us go back five-and-twenty years. I am living at +Orange. My house stands alone among the fields. On the other side of +the wall enclosing our yard, which faces due south, is a narrow path +overgrown with couch-grass. The sun beats full upon it; and the glare +reflected from the whitewash of the wall turns it into a little tropical +corner, shut off from the rude gusts of the north-west wind. + +Here the Cats come to take their afternoon nap, with their eyes +half-closed; here the children come, with Bull, the House-dog; here +also come the haymakers, at the hottest time of the day, to sit and take +their meal and whet their scythes in the shade of the plane-tree; here +the women pass up and down with their rakes, after the hay-harvest, to +glean what they can on the niggardly carpet of the shorn meadow. It is +therefore a very much frequented footpath, were it only because of the +coming and going of our household: a thoroughfare ill-suited, one would +think, to the peaceful operations of a Bee; and nevertheless it is such +a very warm and sheltered spot and the soil is so favourable that every +year I see the Cylindrical Halictus (H. cylindricus, FAB.) hand down +the site from one generation to the next. It is true that the very +matutinal, even partly nocturnal character of the work makes the insect +suffer less inconvenience from the traffic. + +The burrows cover an extent of some ten square yards, and their mounds, +which often come near enough to touch, average a distance of four inches +at the most from one another. Their number is therefore something like +a thousand. The ground just here is very rough, consisting of stones +and dust mixed with a little mould and held together by the closely +interwoven roots of the couch-grass. But, owing to its nature, it is +thoroughly well drained, a condition always in request among Bees and +Wasps that have underground cells. + +Let us forget for a moment what the Zebra Halictus and the Early +Halictus have taught us. At the risk of repeating myself a little, +I will relate what I observed during my first investigations. The +Cylindrical Halictus works in May. Except among the social species, such +as Common Wasps, Bumble-bees, Ants and Hive-bees, it is the rule for +each insect that victuals its nests either with honey or game to work by +itself at constructing the home of its grubs. Among insects of the same +species there is often neighbourship; but their labours are individual +and not the result of co-operation. For instance, the Cricket-hunters, +the Yellow-winged Sphex, settle in gangs at the foot of a sandstone +cliff, but each digs her own burrow and would not suffer a neighbour to +come and help in piercing the home. + +In the case of the Anthophorae, an innumerable swarm takes possession +of a sun-scorched crag, each Bee digging her own gallery and jealously +excluding any of her fellows who might venture to come to the entrance +of her hole. The Three-pronged Osmia, when boring the bramble-stalk +tunnel in which her cells are to be stacked, gives a warm reception to +any Osmia that dares set foot upon her property. + +Let one of the Odyneri who make their homes in a road-side bank mistake +the door and enter her neighbour's house: she would have a bad time of +it! Let a Megachile, returning with her leafy disk in her legs, go +into the wrong basement: she would be very soon dislodged! So with the +others: each has her own home, which none of the others has the right +to enter. This is the rule, even among Bees and Wasps established in a +populous colony on a common site. Close neighbourhood implies no sort of +intimate relationship. + +Great therefore is my surprise as I watch the Cylindrical Halictus' +operations. She forms no society, in the entomological sense of the +word: there is no common family; and the general interest does not +engross the attention of the individual. Each mother occupies herself +only with her own eggs, builds cells and gathers honey only for her own +larvae, without concerning herself in any way with the upbringing of the +others' grubs. All that they have in common is the entrance-door and +the goods-passage, which ramifies in the ground and leads to different +groups of cells, each the property of one mother. Even so, in the blocks +of flats in our large towns, one door, one hall and one staircase lead +to different floors or different portions of a floor where each family +retains its isolation and its independence. + +This common right of way is extremely easy to perceive at the time for +victualling the nests. Let us direct our attention for a while to the +same entrance-aperture, opening at the top of a little mound of earth +freshly thrown up, like that accumulated by the Ants during their works. +Sooner or later we shall see the Halicti arrive with their load of +pollen, gathered on the Cichoriaceae of the neighbourhood. + +Usually, they come up one by one; but it is not rare to see three, four +or even more appearing at the same time at the mouth of one burrow. +They perch on the top of the mound and, without hurrying in front of one +another, with no sign of jealousy, they dive down the passage, each +in her turn. We need but watch their peaceful waiting, their tranquil +dives, to recognize that this indeed is a common passage to which each +has as much right as another. + +When the soil is exploited for the first time and the shaft sunk slowly +from the outside to the inside, do several Cylindrical Halicti, one +relieving the other, take part in the work by which they will afterwards +profit equally? I do not believe it for a moment. As the Zebra Halictus +and the Early Halictus told me later, each miner goes to work alone and +makes herself a gallery which will be her exclusive property. The common +use of the passage comes presently, when the site, tested by experience, +is handed down from one generation to another. + +A first group of cells is established, we will suppose, at the bottom of +a pit dug in virgin soil. The whole thing, cells and pit, is the work of +one insect. When the moment comes to leave the underground dwelling, the +Bees emerging from this nest will find before them an open road, or one +at most obstructed by crumbly matter, which offers less resistance than +the neighbouring soil, as yet untouched. The exit-way will therefore be +the primitive way, contrived by the mother during the construction of +the nest. All enter upon it without any hesitation, for the cells open +straight on it. All, coming and going from the cells to the bottom +of the shaft and from the shaft to the cells, will take part in the +clearing, under the stimulus of the approaching deliverance. + +It is quite unnecessary here to presume among these underground +prisoners a concerted effort to liberate themselves more easily by +working in common: each is thinking only of herself and invariably +returns, after resting, to toil at the inevitable path, the path of +least resistance, in short the passage once dug by the mother and now +more or less blocked up. + +Among the Cylindrical Halicti, any one who wishes emerges from her +cell at her own hour, without waiting for the emergence of the others, +because the cells, grouped in small stacks, have each their special +outlet opening into the common gallery. The result of this arrangement +is that all the inhabitants of one burrow are able to assist, each doing +her share, in the clearing of the exit-shaft. When she feels fatigued, +the worker retires to her undamaged cell and another succeeds her, +impatient to get out rather than to help the first. At last the way is +clear and the Halicti emerge. They disperse over the flowers around as +long as the sun is hot; when the air cools, they go back to the burrows +to spend the night there. + +A few days pass and already the cares of egg-laying are at hand. The +galleries have never been abandoned. The Bees have come to take refuge +there on rainy or very windy days; most, if not all, have returned every +evening at sunset, each doubtless making for her own cell, which is +still intact and which is carefully impressed upon her memory. In a +word, the Cylindrical Halictus does not lead a wandering life; she has a +fixed residence. + +A necessary consequence results from these settled habits: for the +purpose of her laying, the Bee will adopt the identical burrow in which +she was born. The entrance-gallery is ready therefore. Should it need to +be carried deeper, to be pushed in new directions, the builder has but +to extend it at will. The old cells even can serve again, if slightly +restored. + +Thus resuming possession of the native burrow in view of her offspring, +the Bee, notwithstanding her instincts as a solitary worker, achieves +an attempt at social life, because there is one entrance-door and +one passage for the use of all the mothers returning to the original +domicile. There is thus a semblance of collaboration without any real +co-operation for the common weal. Everything is reduced to a family +inheritance shared equally among the heirs. + +The number of these coheirs must soon be limited, for a too tumultuous +traffic in the corridor would delay the work. Then fresh passages are +opened inwards, often communicating with depths already excavated, +so that the ground at last is perforated in every direction with an +inextricable maze of winding tunnels. + +The digging of the cells and the piercing of new galleries take place +especially at night. A cone of fresh earth on top of the burrow bears +evidence every morning to the overnight activity. It also shows by its +volume that several navvies have taken part in the work, for it would be +impossible for a single Halictus to extract from the ground, convey to +the surface and heap up so large a stack of rubbish in so short a time. + +At sunrise, when the fields around are still wet with dew, the +Cylindrical Halictus leaves her underground passages and starts on her +foraging. This is done without animation, perhaps because of the morning +coolness. There is no joyous excitement, no humming above the burrows. +The Bees come back again, flying low, silently and heavily, their +hind-legs yellow with pollen; they alight on the earth-cone and at once +dive down the vertical chimney. Others come up the pipe and go off to +their harvesting. + +This journeying to and fro for provisions continues until eight or nine +in the morning. Then the heat begins to grow intense and is reflected +by the wall; then also the path is once more frequented. People pass at +every moment, coming out of the house or elsewhence. The soil is so much +trodden under foot that the little mounds of refuse surrounding each +burrow soon disappear and the site loses every sign of underground +habitation. + +All day long, the Halicti remain indoors. Withdrawing to the bottom of +the galleries, they occupy themselves probably in making and polishing +the cells. Next morning, new cones of rubbish appear, the result of the +night's work, and the pollen-harvest is resumed for a few hours; then +everything ceases again. And so the work goes on, suspended by day, +renewed at night and in the morning hours, until completely finished. + +The passages of the Cylindrical Halictus descend to a depth of some +eight inches and branch into secondary corridors, each giving access +to a set of cells. These number six or eight to each set and are ranged +side by side, parallel with their main axis, which is almost horizontal. +They are oval at the base and contracted at the neck. Their length is +nearly twenty millimetres (.78 inch.--Translator's Note.) and their +greatest width eight. (.312 inch.--Translator's Note.) They do not +consist simply of a cavity in the ground; on the contrary, they have +their own walls, so that the group can be taken out in one piece, with +a little precaution, and removed neatly from the earth in which it is +contained. + +The walls are formed of fairly delicate materials, which must have +been chosen in the coarse surrounding mass and kneaded with saliva. +The inside is carefully polished and upholstered with a thin waterproof +film. We will cut short these details concerning the cells, which the +Zebra Halictus has already shown us in greater perfection, leave the +home to itself and come to the most striking feature in the life-history +of the Halicti. + +The Cylindrical Halictus is at work in the first days of May. It is +a rule among the Hymenoptera for the males never to take part in +the fatiguing work of nest-building. To construct cells and to amass +victuals are occupations entirely foreign to their nature. This rule +seems to have no exceptions; and the Halicti conform to it like the +rest. It is therefore only to be expected that we should see no males +shooting the underground rubbish outside the galleries. That is not +their business. + +But what does astonish us, when our attention is directed to it, is the +total absence of any males in the vicinity of the burrows. Although it +is the rule that the males should be idle, it is also the rule for these +idlers to keep near the galleries in course of construction, coming and +going from door to door and hovering above the work-yards to seize the +moment at which the unfecundated females will at last yield to their +importunities. + +Now here, despite the enormous population, despite my careful and +incessant watch, it is impossible for me to distinguish a single male. +And yet the distinction between the sexes is of the simplest. It is +not necessary to take hold of the male. He can be recognized even at a +distance by his slenderer frame, by his long, narrow abdomen, by his red +sash. They might easily suggest two different species. The female is +a pale russet-brown; the male is black, with a few red segments to his +abdomen. Well, during the May building-operations, there is not a Bee in +sight clad in black, with a slender, red-belted abdomen; in short, not a +male. + +Though the males do not come to visit the environs of the burrows, they +might be elsewhere, particularly on the flowers where the females go +plundering. I did not fail to explore the fields, insect-net in hand. +My search was invariably fruitless. On the other hand, those males, +now nowhere to be found, are plentiful later, in September, along the +borders of the paths, on the close-set flowers of the eringo. + +This singular colony, reduced exclusively to mothers, made me suspect +the existence of several generations a year, whereof one at least must +possess the other sex. I continued therefore, when the building-who +was over, to keep a daily watch on the establishment of the Cylindrical +Halictus, in order to seize the favourable moment that would verify my +suspicions. For six weeks, solitude reigned above the burrows: not a +single Halictus appeared; and the path, trodden by the wayfarers, lost +its little heaps of rubbish, the only signs of the excavations. There +was nothing outside to show that the warmth down below was hatching +populous swarms. + +July comes and already a few little mounds of fresh earth betoken work +going on underground in preparation for an exodus in the near future. +As the males, among the Hymenoptera, are generally further advanced than +the females and quit their natal cells earlier, it was important that I +should witness the first exits made, so as to dispel the least shadow +of a doubt. A violent exhumation would have a great advantage over the +natural exit: it would place the population of the burrows immediately +under my eyes, before the departure of either sex. In this way, nothing +could escape from me and I was dispensed from a watch which, for all its +attentiveness, was not to be relied upon absolutely. I therefore resolve +upon a reconnaissance with the spade. + +I dig down to the full depth of the galleries and remove large lumps of +earth which I take in my hands and break very carefully so as to examine +all the parts that may contain cells. Halicti in the perfect state +predominate, most of them still lodged in their unbroken chambers. +Though they are not quite so numerous, there are also plenty of pupae. +I collect them of every shade of colour, from dead-white, the sign of +a recent transformation, to smoky-brown, the mark of an approaching +metamorphosis. Larvae, in small quantities, complete the harvest. They +are in the state of torpor that precedes the appearance of the pupa. + +I prepare boxes with a bed of fresh, sifted earth to receive the larvae +and the pupae, which I lodge each in a sort of half-cell formed by the +imprint of my finger. I will await the transformation to decide to which +sex they belong. As for the perfect insects, they are inspected, counted +and at once released. + +In the very unlikely supposition that the distribution of the sexes +might vary in different parts of the colony, I make a second excavation, +at a few yards' distance from the other. It supplies me with another +collection both of perfect insects and of pupae and larvae. + +When the metamorphosis of the laggards is completed, which does not take +many days, I proceed to take a general census. It gives me two hundred +and fifty Halicti. Well, in this number of Bees, collected in the burrow +before any have emerged, I perceive none, absolutely none but females; +or, to be mathematically accurate, I find just one male, one alone; +and he is so small and feeble that he dies without quite succeeding in +divesting himself of his nymphal bands. This solitary male is certainly +accidental. A female population of two hundred and forty-nine Halicti +implies other males than this abortion, or rather implies none at all. I +therefore eliminate him as an accident of no value and conclude that, in +the Cylindrical Halictus, the July generation consists of females only. + +The building-operations start again in the second week of July. The +galleries are restored and lengthened; new cells are fashioned and the +old ones repaired. Follow the provisioning, the laying of the eggs, the +closing of the cells; and, before July is over, there is solitude again. +Let me also say that, during the building-period, not a male appears in +sight, a fact which adds further proof to that already supplied by my +excavations. + +With the high temperature of this time of the year, the development of +the larvae makes rapid progress: a month is sufficient for the various +stages of the metamorphosis. On the 24th of August there are once more +signs of life above the burrows of the Cylindrical Halictus, but under +very different conditions. For the first time, both sexes are present. +Males, so easily recognized by their black livery and their slim abdomen +adorned with a red ring, hover backwards and forwards, almost level with +the ground. They fuss about from burrow to burrow. A few rare females +come out for a moment and then go in again. + +I proceed to make an excavation with my spade; I gather indiscriminately +whatever I come across. Larvae are very scarce; pupae abound, as do +perfect insects. The list of my captures amounts to eighty males and +fifty-eight females. The males, therefore, hitherto impossible to +discover, either on the flowers around or in the neighbourhood of the +burrows, could be picked up to-day by the hundred, if I wished. They +outnumber the females by about four to three; they are also further +developed, in accordance with the general rule, for most of the backward +pupae give me only females. + +Once the two sexes had appeared, I expected a third generation that +would spend the winter in the larval state and recommence in May the +annual cycle which I have just described. My anticipation proved to be +at fault. Throughout September, when the sun beats upon the burrows, +I see the males flitting in great numbers from one shaft to the other. +Sometimes a female appears, returning from the fields, but with no +pollen on her legs. She seeks her gallery, finds it, dives down and +disappears. + +The males, as though indifferent to her arrival, offer her no welcome, +do not harass her with their amorous pursuits; they continue to visit +the doors of the burrows with a winding and oscillating flight. For two +months, I follow their evolutions. If they set foot on earth, it is to +descend forthwith into some gallery that suits them. + +It is not uncommon to see several of them on the threshold of the same +burrow. Then each awaits his turn to enter; they are as peaceable in +their relations as the females who are joint owners of a burrow. At +other times, one wants to go in as a second is coming out. This sudden +encounter produces no strife. The one leaving the hole withdraws a +little to one side to make enough room for two; the other slips past as +best he can. These peaceful meetings are all the more striking when we +consider the usual rivalry between males of the same species. + +No rubbish-mound stands at the mouth of the shafts, showing that the +building has not been resumed; at the most, a few crumbs of earth are +heaped outside. And by whom, pray? By the males and by them alone. The +lazy sex has bethought itself of working. It turns navvy and shoots out +grains of earth that would interfere with its continual entrances and +exits. For the first time I witness a custom which no Hymenopteron had +yet shown me: I see the males haunting the interior of the burrows with +an assiduity equalling that of the mothers employed in nest-building. + +The cause of these unwonted operations soon stands revealed. The females +seen flitting above the burrows are very rare; the majority of the +feminine population remain sequestered under ground, do not perhaps come +out once during the whole of the latter part of summer. Those who do +venture out go in again soon, empty-handed of course and always without +any amorous teasing from the males, a number of whom are hovering above +the burrows. + +On the other hand, watch as carefully as I may, I do not discover +a single act of pairing out of doors. The weddings are clandestine, +therefore, and take place under ground. This explains the males' fussy +visits to the doors of the galleries during the hottest hours of the +day, their continual descents into the depths and their continual +reappearances. They are looking for the females cloistered in the +retirement of the cells. + +A little spade-work soon turns suspicion into certainty. I unearth a +sufficient number of couples to prove to me that the sexes come together +underground. When the marriage is consummated, the red-belted one quits +the spot and goes to die outside the burrow, after dragging from flower +to flower the bit of life that remains to him. The other shuts herself +up in her cell, there to await the return of the month of May. + +September is spent by the Halictus solely in nuptial celebrations. +Whenever the sky is fine, I witness the evolutions of the males above +the burrows, with their continual entrances and exits; should the sun +be veiled, they take refuge down the passages. The more impatient, +half-hidden in the pit, show their little black heads outside, as though +peeping for the least break in the clouds that will allow them to pay a +brief visit to the flowers round about. They also spend the night in the +burrows. In the morning, I attend their levee; I see them put their head +to the window, take a look at the weather and then go in again until the +sun beats on the encampment. + +The same mode of life is continued throughout October, but the males +become less numerous from day to day as the stormy season approaches +and fewer females remain to be wooed. By the time that the first cold +weather comes, in November, complete solitude reigns over the burrows. +I once more have recourse to the spade. I find none but females in their +cells. There is not one male left. All have vanished, all are dead, the +victims of their life of pleasure and of the wind and rain. Thus ends +the cycle of the year for the Cylindrical Halictus. + +In February, after a hard winter, when the snow had lain on the ground +for a fortnight, I wanted once more to look into the matter of my +Halicti. I was in bed with pneumonia and at the point of death, to all +appearances. I had little or no pain, thank God, but extreme difficulty +in living. With the little lucidity left to me, being able to do no +other sort of observing, I observed myself dying; I watched with a +certain interest the gradual falling to pieces of my poor machinery. +Were it not for the terror of leaving my family, who were still young, I +would gladly have departed. The after-life must have so many higher and +fairer truths to teach us. + +My hour had not yet come. When the little lamps of thought began to +emerge, all flickering, from the dusk of unconsciousness, I wished to +take leave of the Hymenopteron, my fondest joy, and first of all of my +neighbour, the Halictus. My son Emile took the spade and went and dug +the frozen ground. Not a male was found, of course; but there were +plenty of females, numbed with the cold in their cells. + +A few were brought for me to see. Their little chambers showed no +efflorescence of rime, with which all the surrounding earth was coated. +The waterproof varnish had been wonderfully efficacious. As for the +anchorites, roused from their torpor by the warmth of the room, they +began to wander about my bed, where I followed them vaguely with my +fading eyes. + +May came, as eagerly awaited by the sick man as by the Halicti. I left +Orange for Serignan, my last stage, I expect. While I was moving, the +Bees resumed their building. I gave them a regretful glance, for I had +still much to learn in their company. I have never since met with such a +mighty colony. + +These old observations on the habits of the Cylindrical Halictus may now +be followed by a general summary which will incorporate the recent data +supplied by the Zebra Halictus and the Early Halictus. + +The females of the Cylindrical Halictus whom I unearth from November +onwards are evidently fecundated, as is proved by the assiduity of the +males during the preceding two months and most positively confirmed by +the couples discovered in the course of my excavations. These females +spend the winter in their cells, as do many of the early-hatching +melliferous insects, such as Anthophorae and Mason-bees, who build their +nests in the spring, the larvae reaching the perfect state in the summer +and yet remaining shut up in their cells until the following May. But +there is this great difference in the case of the Cylindrical Halictus, +that in the autumn the females leave their cells for a time to receive +the males under ground. The couples pair and the males perish. Left +alone, the females return to their cells, where they spend the inclement +season. + +The Zebra Halicti, studied first at Orange and then, under better +conditions, at Serignan, in my own enclosure, have not these +subterranean customs: they celebrate their weddings amid the joys of +the light, the sun and the flowers. I see the first males appear in the +middle of September, on the centauries. Generally there are several of +them courting the same bride. Now one, then another, they swoop upon her +suddenly, clasp her, leave her, seize hold of her again. Fierce brawls +decide who shall possess her. One is accepted and the others decamp. +With a swift and angular flight, they go from flower to flower, without +alighting. They hover on the wing, looking about them, more intent on +pairing than on eating. + +The Early Halictus did not supply me with any definite information, +partly through my own fault, partly through the difficulty of excavation +in a stony soil, which calls for the pick-axe rather than the spade. I +suspect her of having the nuptial customs of the Cylindrical Halictus. + +There is another difference, which causes certain variations of detail +in these customs. In the autumn, the females of the Cylindrical Halictus +leave their burrows seldom or not at all. Those who do go out invariably +come back after a brief halt upon the flowers. All pass the winter in +the natal cells. On the other hand, those of the Zebra Halictus move +their quarters, meet the males outside and do not return to the burrows, +which my autumn excavations always find deserted. They hibernate in the +first hiding-places that offer. + +In the spring, the females, fecundated since the autumn, come out: +the Cylindrical Halicti from their cells, the Zebra Halicti from their +various shelters, the Early Halicti apparently from their chambers, like +the first. They work at their nests in the absence of any male, as do +also the Social Wasps, whose whole brood has perished excepting a few +mothers also fecundated in the autumn. In both cases, the assistance of +the males is equally real, only it has preceded the laying by about six +months. + +So far, there is nothing new in the life of the Halicti; but here is +where the unexpected appears: in July, another generation is produced; +and this time without males. The absence of masculine assistance is no +longer a mere semblance here, due to an earlier fecundation: it is a +reality established beyond a doubt by the continuity of my observations +and by my excavations during the summer season, before the emergence of +the new Bees. At this period, a little before July, if my spade unearth +the cells of any one of my three Halicti, the result is always females, +nothing but females, with exceedingly rare exceptions. + +True, it may be said that the second progeny is due to the mothers who +knew the males in autumn and who would be able to nidify twice a year. +The suggestion is not admissible. The Zebra Halictus confirms what +I say. She shows us the old mothers no longer leaving the home but +mounting guard at the entrance to the burrows. No harvesting- or +pottery-work is possible with these absorbing doorkeeping-functions. +Therefore there is no new family, even admitting that the mothers' +ovaries are not depleted. + +I do not know if a similar argument is valid in the case of the +Cylindrical Halictus. Has she any general survivors? As my attention +had not yet been directed on this point in the old days, when I had +the insect at my door, I have no records to go upon. For all that, I +am inclined to think that the portress of the Zebra Halictus is unknown +here. The reason of this absence would be the number of workers at the +start. + +In May, the Zebra Halictus, living by herself in her winter retreat, +founds her house alone. When her daughters succeed her, in July, she is +the only grandmother in the establishment and the post of portress falls +to her. With the Cylindrical Halictus, the conditions are different. +Here the May workers are many in the same burrow, where they dwell in +common during the winter. Supposing that they survive when the business +of the household is finished, to whom will the office of overseer fall? +Their number is so great and they are all so full of zeal that disorder +would be inevitable. But we can leave this small matter unsettled +pending further information. + +The fact remains that females, females exclusively, have come out of the +eggs laid in May. They have descendants, of that there is no room for +doubt; they procreate though there are no males in their time. From +this generation by a single sex, there spring, two months later, males +and females. These mate; and the same order of things recommences. + +To sum up, judging by the three species that form the subject of my +investigations, the Halicti have two generations a year: one in the +spring, issuing from the mothers who have lived through the winter after +being fecundated in the autumn; the other in the summer, the fruit of +parthenogenesis, that is to say, of reproduction by the powers of the +mother alone. Of the union of the two sexes, females alone are born; +parthenogenesis gives birth at the same time to females and males. + +When the mother, the original genitrix, has been able once to dispense +with a coadjutor, why does she need one later? What is the puny idler +there for? He was unnecessary. Why does he become necessary now? Shall +we ever obtain a satisfactory answer to the question? It is doubtful. +However, without much hope of succeeding we will one day consult the +Gall-fly, who is better-versed than we in the tangled problem of the +sexes. + + + +INDEX. + +Alpine Odynerus. + +Amadeus' Eumenes. + +Ammophila (see also Hairy Ammophila). + +Andrena. + +Andrenoid Osmia. + +Ant. + +Anthidium (see the varieties below, Cotton-bee, Resin Bee). + +Anthidium bellicosum. + +Anthidium cingulatum (see Girdled Anthidium). + +Anthidium diadema (see Diadem Anthidium). + +Anthidium florentinum (see Florentine Anthidium). + +Anthidium Latreillii (see Latreille's Resin-bee). + +Anthidium manicatum (see Manicate Anthidium). + +Anthidium quadrilobum (see Four-lobed Resin-bee). + +Anthidium scapulare (see Scapular Anthidium). + +Anthidium septemdentatum (see Seven-pronged Resin-bee). + +Anthocopa papaveris (see Upholsterer-bee). + +Anthophora (see also Anthophora of the Walls, Hairy-footed Anthophora, +Masked Anthophora). + +Anthophora of the Walls. + +Anthophora parietina (see Anthophora of the Walls). + +Anthophora pilipes (see Hairy-footed Anthophora). + +Anthrax (see Anthrax sinuata). + +Anthrax sinuata. + +Aphis (see Plant-louse). + +Archimedes. + +Augustus, the Emperor. + +Bee. + +Beetle. + +Bembex. + +Black, Adam and Charles. + +Black Plant-louse. + +Black Psen. + +Black-tipped Leaf-cutter. + +Blue Osmia. + +Book-louse. + +Brown Snail. + +Bulimulus radiatus. + +Bumble-bee. + +Calicurgus (see Pompilus). + +Capricorn. + +Carpenter-bee. + +Cat. + +Cemonus unicolor. + +Cerambyx (see Capricorn). + +Ceratina (see also the varieties below). + +Ceratina albilabris. + +Ceratina callosa. + +Ceratina chalcites. + +Ceratina coerulea. + +Cerceris. + +Cetonia. + +Chaffinch. + +Chalicodoma (see Mason-bee). + +Chrysis flammea. + +Cockroach. + +Coelyoxis caudata. + +Coelyoxis octodentata. + +Colletes. + +Common Snail. + +Common Wasp. + +Cotton-bee (see also the varieties of Anthidium). + +Crayfish. + +Cricket. + +Crioceris merdigera (see Lily-beetle). + +Cryptus bimaculatus. + +Cryptus gyrator. + +Cylindrical Halictus. + +Darwin, Charles Robert. + +Decticus verrucivorus. + +Devillario, Henri. + +Diadem Anthidium. + +Dioxys cincta. + +Dog. + +Dragon-fly. + +Dryden, John. + +Dufour, Jean Marie Leon. + +Dung-beetle. + +Dzierzon, Johann. + +Early Halictus. + +Earth-worm. + +Earwig. + +Epeira (see Garden Spider). + +Ephialtes divinator. + +Ephialtes mediator. + +Ephippiger. + +Eumenes Amadei (see Amadeus' Eumenes). + +Euritema rubicola. + +Fabre, Emile, the author's son. + +Fabricius, Johann Christian. + +Feeble Leaf-cutter. + +Field-mouse. + +Florentine Anthidium. + +Fly (see also House-fly). + +Foenus pyrenaicus. + +Four-lobed Resin-bee. + +Franklin, Benjamin. + +Garden Snail. + +Garden Spider. + +Girdled Anthidium. + +Girdled Snail (see Brown Snail). + +Gnat. + +Golden Osmia. + +Goldfinch. + +Grasshopper (see also Great Green Grasshopper). + +Great Green Grasshopper. + +Great Peacock Moth. + +Green Grasshopper (see Ephippiger, Great Green Grasshopper). + +Green Osmia. + +Grey Lizard. + +Hairy Ammophila. + +Hairy-footed Anthophora. + +Halictus (see also the varieties below). + +Halictus cylindricus (see Cylindrical Halictus). + +Halictus malachurus (see Early Halictus). + +Halictus zebrus (see Zebra Halictus). + +Hare-footed Leaf-cutter. + +Helix algira. + +Helix aspersa (see Common Snail). + +Helix caespitum (see Garden Snail). + +Helix nemoralis. + +Helix striata. + +Heriades rubicola. + +Herring. + +Hive-bee. + +Honey-bee (see Hive-bee). + +Horned Osmia. + +House-dog (see Dog). + +House-fly. + +Kid. + +Kirby, William. + +La Fontaine, Jean de. + +Lamb. + +Languedocian Sphex. + +Lanius collurio (see Red-backed Shrike). + +La Palice, Jacques de Chabannes, Seigneur de. + +Latreille, Pierre Andre. + +Latreille's Osmia. + +Latreille's Resin-bee. + +Leaf-cutter, Leaf-cutting Bee (see Megachile). + +Leaf-insect. + +Leucopsis. + +Lily-beetle. + +Lithurgus (see also the varieties below). + +Lithurgus chrysurus. + +Lithurgus cornutus. + +Lizard (see also Grey Lizard). + +Locust. + +Locusta viridissima (see Great Green Grasshopper). + +Macmillan Co. + +"Mademoiselle Mori", author of. + +Manicate Anthidium. + +Mantis, Mantis religiosa (see Praying Mantis). + +Masked Anthophora. + +Mason-bee (see also the varieties below). + +Mason-bee of the Pebbles (see Mason-bee of the Walls). + +Mason-bee of the Sheds. + +Mason-bee of the Shrubs. + +Mason-bee of the Walls. + +May-fly. + +Meade-Waldo, Geoffrey. + +Megachile (see also the varieties below). + +Megachile albocincta (see White-girdled Leaf-cutter). + +Megachile apicalis (see Black-tipped Leaf-cutter). + +Megachile argentata (see Silvery Leaf-cutter). + +Megachile Dufourii (see Silky Leaf-cutter). + +Megachile imbecilla (see Feeble Leaf-cutter). + +Megachile lagopoda (see Hare-footed Leaf-cutter). + +Megachile sericans (see Silky Leaf-cutter). + +Melitta (see Colletes). + +Miall, Bernard. + +Midwife Toad. + +Morawitz' Osmia. + +Odynerus (see also the varieties below) + +Odynerus alpestris (see Alpine Odynerus). + +Odynerus delphinalis. + +Odynerus rubicola. + +Oil-beetle. + +Omalus auratus. + +Osmia (see also the varieties below). + +Osmia andrenoides (see Andrenoid Osmia). + +Osmia aurulenta (see Golden Osmia). + +Osmia cornuta (see Horned Osmia). + +Osmia cyanea (see Blue Osmia). + +Osmia cyanoxantha. + +Osmia detrita (see Ragged Osmia). + +Osmia Latreillii (see Latreille's Osmia). + +Osmia Morawitzi (see Morawitz' Osmia). + +Osmia parvula (see Tiny Osmia). + +Osmia rufo-hirta (see Red Osmia). + +Osmia tricornis (see Three-horned Osmia). + +Osmia tridentata (see Three-pronged Osmia). + +Osmia versicolor (see Variegated Osmia). + +Osmia viridana (see Green Osmia). + +Pelopaeus. + +Perez, Professor Jean. + +Philanthus (see Philanthus apivorus). + +Philanthus apivorus. + +Plant-louse (see also Black Plant-louse). + +Pompilus. + +Praying Mantis. + +Prosopis confusa. + +Psen atratus (see Black Psen). + +Rabelais, Francois. + +Ragged Osmia. + +Reaumur, Rene Antoine Ferchault de. + +Red-backed Shrike. + +Red-Osmia. + +Resin-bee (see also the varieties). + +Ringed Calicurgus (see Pompilus). + +Rodwell, Miss Frances. + +Rosechafer (see Cetonia). + +Sapyga (see Spotted Sapyga). + +Sardine. + +Scapular Anthidium. + +Scolia. + +Scorpion. + +Seven-pronged Resin-bee. + +Shrike (see Red-backed Shrike). + +Silky Leaf-cutter. + +Silvery Leaf-cutter. + +Snail (see also the varieties) + +Social Wasp (see Common Wasp). + +Solenius lapidarius. + +Solenius vagus. + +Sophocles. + +Sparrow. + +Spence, William. + +Sphex (see also Languedocian Sphex, Yellow-winged Sphex.) + +Spotted Sapyga. + +Stick-insect. + +Stizus. + +Tachina. + +Tachytes. + +Tarantula. + +Teixeira de Mattos, Alexander. + +Termite. + +Three-horned Osmia. + +Three-pronged Osmia. + +Tiberius, the Emperor. + +Tiny Osmia. + +Tripoxylon figulus. + +Unarmed Zonitis (see Zonitis mutica). + +Upholsterer-bee. + +Variegated Osmia. + +Virgil. + +Wasp (see also Common Wasp). + +Weaving Spider. + +Weevil. + +White-girdled Leaf-cutter. + +Wolf. + +Worm (see Earth-worm). + +Xylocopa violacea (see Carpenter-bee). + +Yellow-winged Sphex. + +Zebra Halictus. + +Zonitis mutica. + + + + + +End of Project Gutenberg's Bramble-bees and Others, by J. 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FOR PUBLIC DOMAIN ETEXTS*Ver.12.12.00*END* + + + + + +This etext was produced by Sue Asscher <asschers@dingoblue.net.au> + + + + + +BRAMBLE-BEES AND OTHERS + +by J. HENRI FABRE + + + + +TRANSLATED BY ALEXANDER TEIXEIRA DE MATTOS, F.Z.S. + +TRANSLATOR'S NOTE. + +In this volume I have collected all the essays on Wild Bees scattered +through the "Souvenirs entomologiques," with the exception of those +on the Chalicodomae, or Mason-bees proper, which form the contents of +a separate volume entitled "The Mason-bees." + +The first two essays on the Halicti (Chapters 12 and 13) have already +appeared in an abbreviated form in "The Life and Love of the Insect," +translated by myself and published by Messrs. A. & C. Black (in +America by the Macmillan Co.) in 1911. With the greatest courtesy and +kindness, Messrs. Black have given me their permission to include +these two chapters in the present volume; they did so without fee or +consideration of any kind, merely on my representation that it would +be a great pity if this uniform edition of Fabre's Works should be +rendered incomplete because certain essays formed part of volumes of +extracts previously published in this country. Their generosity is +almost unparalleled in my experience; and I wish to thank them +publicly for it in the name of the author, of the French publishers +and of the English and American publishers, as well as in my own. + +Of the remaining chapters, one or two have appeared in the "English +Review" or other magazines; but most of them now see the light in +English for the first time. + +I have once more, as in the case of "The Mason-bees," to thank Miss +Frances Rodwell for the help which she has given me in the work of +translation and research; and I am also grateful for much kind +assistance received from the staff of the Natural History Museum and +from Mr. Geoffrey Meade-Waldo in particular. + +ALEXANDER TEIXEIRA DE MATTOS. + +Chelsea, 1915. + + + + +CONTENTS. + +TRANSLATOR'S NOTE. + +CHAPTER 1. BRAMBLE-DWELLERS. + +CHAPTER 2. THE OSMIAE. + +CHAPTER 3. THE DISTRIBUTION OF THE SEXES. + +CHAPTER 4. THE MOTHER DECIDES THE SEX OF THE EGG. + +CHAPTER 5. PERMUTATIONS OF SEX. + +CHAPTER 6. INSTINCT AND DISCERNMENT. + +CHAPTER 7. ECONOMY OF ENERGY. + +CHAPTER 8. THE LEAF-CUTTERS. + +CHAPTER 9. THE COTTON-BEES. + +CHAPTER 10. THE RESIN-BEES. + +CHAPTER 11. THE POISON OF THE BEE. + +CHAPTER 12. THE HALICTI: A PARASITE. + +CHAPTER 13. THE HALICTI: THE PORTRESS. + +CHAPTER 14. THE HALICTI: PARTHENOGENESIS. + +INDEX. + + + + +CHAPTER 1. BRAMBLE-DWELLERS. + +The peasant, as he trims his hedge, whose riotous tangle threatens to +encroach upon the road, cuts the trailing stems of the bramble a foot +or two from the ground and leaves the root-stock, which soon dries +up. These bramble-stumps, sheltered and protected by the thorny +brushwood, are in great demand among a host of Hymenoptera who have +families to settle. The stump, when dry, offers to any one that knows +how to use it a hygienic dwelling, where there is no fear of damp +from the sap; its soft and abundant pith lends itself to easy work; +and the top offers a weak spot which makes it possible for the insect +to reach the vein of least resistance at once, without cutting away +through the hard ligneous wall. To many, therefore, of the Bee and +Wasp tribe, whether honey-gatherers or hunters, one of these dry +stalks is a valuable discovery when its diameter matches the size of +its would-be inhabitants; and it is also an interesting subject of +study to the entomologist who, in the winter, pruning-shears in hand, +can gather in the hedgerows a faggot rich in small industrial +wonders. Visiting the bramble-bushes has long been one of my +favourite pastimes during the enforced leisure of the wintertime; and +it is seldom but some new discovery, some unexpected fact, makes up +to me for my torn fingers. + +My list, which is still far from being complete, already numbers +nearly thirty species of bramble-dwellers in the neighbourhood of my +house; other observers, more assiduous than I, exploring another +region and one covering a wider range, have counted as many as fifty. +I give at foot an inventory of the species which I have noted. + +(Bramble-dwelling insects in the neighbourhood of Serignan +(Vaucluse): + +1. MELLIFEROUS HYMENOPTERA. +Osmia tridentata, DUF. and PER. +Osmia detrita, PEREZ. +Anthidium scapulare, LATR. +Heriades rubicola, PEREZ. +Prosopis confusa, SCHENCK. +Ceratina chalcites, GERM. +Ceratina albilabris, FAB. +Ceratina callosa, FAB. +Ceratina coerulea, VILLERS. + +2. HUNTING HYMENOPTERA. +Solenius vagus, FAB. (provisions, Diptera). +Solenius lapidarius, LEP. (provisions, Spiders?). +Cemonus unicolor, PANZ. (provisions, Plant-lice). +Psen atratus (provisions, Black Plant-lice). +Tripoxylon figulus, LIN. (provisions, Spiders). +A Pompilus, unknown (provisions, Spiders). +Odynerus delphinalis, GIRAUD. + +3. PARASITICAL HYMENOPTERA. +A Leucopsis, unknown (parasite of Anthidium scapulare). +A small Scoliid, unknown (parasite of Solenius vagus). +Omalus auratus (parasite of various bramble-dwellers). +Cryptus bimaculatus, GRAV. (parasite of Osmia detrita). +Cryptus gyrator, DUF. (parasite of Tripoxylon figulus). +Ephialtes divinator, ROSSI (parasite of Cemonus unicolor). +Ephialtes mediator, GRAV. (parasite of Psen atratus). +Foenus pyrenaicus, GUERIN. +Euritoma rubicola, J. GIRAUD (parasite of Osmia detrita). + +4. COLEOPTERA. +Zonitis mutica, FAB. (parasite of Osmia tridentata). + +Most of these insects have been submitted to a learned expert, +Professor Jean Perez, of Bordeaux. I take this opportunity of +renewing my thanks for his kindness in identifying them for me.-- +Author's Note.) + +They include members of very diverse corporations. Some, more +industrious and equipped with better tools, remove the pith from the +dry stem and thus obtain a vertical cylindrical gallery, the length +of which may be nearly a cubit. This sheath is next divided, by +partitions, into more or less numerous storeys, each of which forms +the cell of a larva. Others, less well-endowed with strength and +implements, avail themselves of the old galleries of other insects, +galleries that have been abandoned after serving as a home for their +builder's family. Their only work is to make some slight repairs in +the ruined tenement, to clear the channel of its lumber, such as the +remains of cocoons and the litter of shattered ceilings, and lastly +to build new partitions, either with a plaster made of clay or with a +concrete formed of pith-scrapings cemented with a drop of saliva. + +You can tell these borrowed dwellings by the unequal size of the +storeys. When the worker has herself bored the channel, she +economizes her space: she knows how costly it is. The cells, in that +case, are all alike, the proper size for the tenant, neither too +large nor too small. In this box, which has cost weeks of labour, the +insect has to house the largest possible number of larvae, while +allotting the necessary amount of room to each. Method in the +superposition of the floors and economy of space are here the +absolute rule. + +But there is evidence of waste when the insect makes use of a bramble +hollowed by another. This is the case with Tripoxylon figulus. To +obtain the store-rooms wherein to deposit her scanty stock of +Spiders, she divides her borrowed cylinder into very unequal cells, +by means of slender clay partitions. Some are a centimetre (.39 +inch.--Translator's Note.) deep, the proper size for the insect; +others are as much as two inches. These spacious rooms, out of all +proportion to the occupier, reveal the reckless extravagance of a +casual proprietress whose title-deeds have cost her nothing. + +But, whether they be the original builders or labourers touching up +the work of others, they all alike have their parasites, who +constitute the third class of bramble-dwellers. These have neither +galleries to excavate nor victuals to provide; they lay their egg in +a strange cell; and their grub feeds either on the provisions of the +lawful owner's larva or on that larva itself. + +At the head of this population, as regards both the finish and the +magnitude of the structure, stands the Three-pronged Osmia (Osmia +tridentata, DUF. and PER.), to whom this chapter shall be specially +devoted. Her gallery, which has the diameter of a lead pencil, +sometimes descends to a depth of twenty inches. It is at first almost +exactly cylindrical; but, in the course of the victualling, changes +occur which modify it slightly at geometrically determined distances. +The work of boring possesses no great interest. In the month of July, +we see the insect, perched on a bramble-stump, attack the pith and +dig itself a well. When this is deep enough, the Osmia goes down, +tears off a few particles of pith and comes up again to fling her +load outside. This monotonous labour continues until the Bee deems +the gallery long enough, or until, as often happens, she finds +herself stopped by an impassable knot. + +Next comes the ration of honey, the laying of the egg and the +partitioning, the last a delicate operation to which the insect +proceeds by degrees from the base to the top. At the bottom of the +gallery, a pile of honey is placed and an egg laid upon the pile; +then a partition is built to separate this cell from the next, for +each larva must have its special chamber, about a centimetre and a +half (.58 inch.--Translator's Note.) long, having no communication +with the chambers adjoining. The materials employed for this +partition are bramble-sawdust, glued into a paste with the insects' +saliva. Whence are these materials obtained? Does the Osmia go +outside, to gather on the ground the rubbish which she flung out when +boring the cylinder? On the contrary, she is frugal of her time and +has better things to do than to pick up the scattered particles from +the soil. The channel, as I said, is at first uniform in size, almost +cylindrical; its sides still retain a thin coating of pith, forming +the reserves which the Osmia, as a provident builder, has economized +wherewith to construct the partitions. So she scrapes away with her +mandibles, keeping within a certain radius, a radius that corresponds +with the dimensions of the cell which she is going to build next; +moreover, she conducts her work in such a way as to hollow out more +in the middle and leave the two ends contracted. In this manner, the +cylindrical channel of the start is succeeded, in the worked portion, +by an ovoid cavity flattened at both ends, a space resembling a +little barrel. This space will form the second cell. + +As for the rubbish, it is utilized on the spot for the lid or cover +that serves as a ceiling for one cell and a floor for the next. Our +own master-builders could not contrive more successfully to make the +best use of their labourers' time. On the floor thus obtained, a +second ration of honey is placed; and an egg is laid on the surface +of the paste. Lastly, at the upper end of the little barrel, a +partition is built with the scrapings obtained in the course of the +final work on the third cell, which itself is shaped like a flattened +ovoid. And so the work goes on, cell upon cell, each supplying the +materials for the partition separating it from the one below. On +reaching the end of the cylinder, the Osmia closes up the case with a +thick layer of the same mortar. Then that bramble-stump is done with; +the Bee will not return to it. If her ovaries are not yet exhausted, +other dry stems will be exploited in the same fashion. + +The number of cells varies greatly, according to the qualities of the +stalk. If the bramble-stump be long, regular and smooth, we may count +as many as fifteen: that, at least, is the highest figure which my +observations have supplied. To obtain a good idea of the internal +distribution, we must split the stalk lengthwise, in the winter, when +the provisions have long been consumed and when the larvae are +wrapped in their cocoons. We then see that, at regular intervals, the +case becomes slightly narrower; and in each of the necks thus formed +a circular disk is fixed, a partition one or two millimetres thick. +(.039 to .079 inch.--Translator's Note.) The rooms separated by these +partitions form so many little barrels or kegs, each compactly filled +with a reddish, transparent cocoon, through which the larva shows, +bent into a fish-hook. The whole suggests a string of rough, oval +amber beads, touching at their amputated ends. + +In this string of cocoons, which is the oldest, which the youngest? +The oldest is obviously the bottom one, the one whose cell was the +first built; the youngest is the one at the top of the row, the one +in the cell last built. The oldest of the larvae starts the pile, +down at the bottom of the gallery; the latest arrival ends it at the +top; and those in between follow upon one another, according to age, +from base to apex. + +Let us next observe that there is no room in the shaft for two Osmiae +at a time on the same level, for each cocoon fills up the storey, the +keg that belongs to it, without leaving any vacant space; let us also +remark that, when they attain the stage of perfection, the Osmiae +must all emerge from the shaft by the only orifice which the bramble- +stem boasts, the orifice at the top. There is here but one obstacle, +easy to overcome: a plug of glued pith, of which the insect's +mandibles make short work. Down below, the stalk offers no ready +outlet; besides, it is prolonged underground indefinitely by the +roots. Everywhere else is the ligneous fence, generally too hard and +thick to break through. It is inevitable therefore that all the +Osmiae, when the time comes to quit their dwelling, should go out by +the top; and, as the narrowness of the shaft bars the passage of the +preceding insect as long as the next insect, the one above it, +remains in position, the removal must begin at the top, extend from +cell to cell and end at the bottom. Consequently, the order of exit +is the converse to the order of birth: the younger Osmiae leave the +nest first, their elders leave it last. + +The oldest, that is to say, the bottom one, was the first to finish +her supply of honey and to spin her cocoon. Taking precedence of all +her sisters in the whole series of her actions, she was the first to +burst her silken bag and to destroy the ceiling that closes her room: +at least, that is what the logic of the situation takes for granted. +In her anxiety to get out, how will she set about her release? The +way is blocked by the nearest cocoons, as yet intact. To clear +herself a passage through the string of those cocoons would mean to +exterminate the remainder of the brood; the deliverance of one would +mean the destruction of all the rest. Insects are notoriously +obstinate in their actions and unscrupulous in their methods. If the +Bee at the bottom of the shaft wants to leave her lodging, will she +spare those who bar her road? + +The difficulty is great, obviously; it seems insuperable. Thereupon +we become suspicious: we begin to wonder if the emergence from the +cocoon, that is to say, the hatching, really takes place in the order +of primogeniture. Might it not be--by a very singular exception, it +is true, but one which is necessary in such circumstances--that the +youngest of the Osmiae bursts her cocoon first and the oldest last; +in short, that the hatching proceeds from one chamber to the next in +the inverse direction to that which the age of the occupants would +lead us to presume? In that case, the whole difficulty would be +removed: each Osmia, as she rent her silken prison, would find a +clear road in front of her, the Osmiae nearer the outlet having gone +out before her. But is this really how things happen? Our theories +very often do not agree with the insect's practice; even where our +reasoning seems most logical, we should be more prudent to see what +happens before venturing on any positive statements. Leon Dufour was +not so prudent when he, the first in the field, took this little +problem in hand. He describes to us the habits of an Odynerus +(Odynerus rubicola, DUF.) who piles up clay cells in the shaft of a +dry bramble-stalk; and, full of enthusiasm for his industrious Wasp, +he goes on to say: + +'Picture a string of eight cement shells, placed end to end and +closely wedged inside a wooden sheath. The lowest was undeniably made +first and consequently contains the first-laid egg, which, according +to rules, should give birth to the first winged insect. How do you +imagine that the larva in that first shell was bidden to waive its +right of primogeniture and only to complete its metamorphosis after +all its juniors? What are the conditions brought into play to produce +a result apparently so contrary to the laws of nature? Humble +yourself in the presence of the reality and confess your ignorance, +rather than attempt to hide your embarrassment under vain +explanations! + +'If the first egg laid by the busy mother were destined to be the +first-born of the Odyneri, that one, in order to see the light +immediately after achieving wings, would have had the option either +of breaking through the double walls of his prison or of perforating, +from bottom to top, the seven shells ahead of him, in order to emerge +through the truncate end of the bramble-stem. Now nature, while +refusing any way of escape laterally, was also bound to veto any +direct invasion, the brutal gimlet-work which would inevitably have +sacrificed seven members of one family for the safety of an only son. +Nature is as ingenious in design as she is fertile in resource, and +she must have foreseen and forestalled every difficulty. She decided +that the last-built cradle should yield the first-born child; that +this one should clear the road for his next oldest brother, the +second for the third and so on. And this is the order in which the +birth of our Odyneri of the Brambles actually takes place.' + +Yes, my revered master, I will admit without hesitation that the +bramble-dwellers leave their sheath in the converse order to that of +their ages: the youngest first, the oldest last; if not invariably, +at least very often. But does the hatching, by which I mean the +emergence from the cocoon, take place in the same order? Does the +evolution of the elder wait upon that of the younger, so that each +may give those who would bar his passage time to effect their +deliverance and to leave the road clear? I very much fear that logic +has carried your deductions beyond the bounds of reality. Rationally +speaking, my dear sir, nothing could be more accurate than your +inferences; and yet we must forgo the theory of the strange inversion +which you suggest. None of the Bramble-bees with whom I have +experimented behaves after that fashion. I know nothing personal +about Odynerus rubicola, who appears to be a stranger in my district; +but, as the method of leaving must be almost the same when the +habitation is exactly similar, it is enough, I think, to experiment +with some of the bramble-dwellers in order to learn the history of +the rest. + +My studies will, by preference, bear upon the Three-pronged Osmia, +who lends herself more readily to laboratory experiments, both +because she is stronger and because the same stalk will contain a +goodly number of her cells. The first fact to be ascertained is the +order of hatching. I take a glass tube, closed at one end, open at +the other and of a diameter similar to that of the Osmia's tunnel. In +this I place, one above the other, exactly in their natural order, +the ten cocoons, or thereabouts, which I extract from a stump of +bramble. The operation is performed in winter. The larvae, at that +time, have long been enveloped in their silken case. To separate the +cocoons from one another, I employ artificial partitions consisting +of little round disks of sorghum, or Indian millet, about half a +centimetre thick. (About one-fifth of an inch.--Translator's Note.) +This is a white pith, divested of its fibrous wrapper and easy for +the Osmia's mandibles to attack. My diaphragms are much thicker than +the natural partitions; this is an advantage, as we shall see. In any +case, I could not well use thinner ones, for these disks must be able +to withstand the pressure of the rammer which places them in position +in the tube. On the other hand, the experiment showed me that the +Osmia makes short work of the material when it is a case of drilling +a hole through it. + +To keep out the light, which would disturb my insects destined to +spend their larval life in complete darkness, I cover the tube with a +thick paper sheath, easy to remove and replace when the time comes +for observation. Lastly, the tubes thus prepared and containing +either Osmiae or other bramble-dwellers are hung vertically, with the +opening at the top, in a snug corner of my study. Each of these +appliances fulfils the natural conditions pretty satisfactorily: the +cocoons from the same bramble-stick are stacked in the same order +which they occupied in the native shaft, the oldest at the bottom of +the tube and the youngest close to the orifice; they are isolated by +means of partitions; they are placed vertically, head upwards; +moreover, my device has the advantage of substituting for the opaque +wall of the bramble a transparent wall which will enable me to follow +the hatching day by day, at any moment which I think opportune. + +The male Osmia splits his cocoon at the end of June and the female at +the beginning of July. When this time comes, we must redouble our +watch and inspect the tubes several times a day if we would obtain +exact statistics of the births. Well, during the six years that I +have studied this question, I have seen and seen again, ad nauseam; +and I am in a position to declare that there is no order governing +the sequence of hatchings, absolutely none. The first cocoon to burst +may be the one at the bottom of the tube, the one at the top, the one +in the middle or in any other part, indifferently. The second to be +split may adjoin the first or it may be removed from it by a number +of spaces, either above or below. Sometimes several hatchings occur +on the same day, within the same hour, some farther back in the row +of cells, some farther forward; and this without any apparent reason +for the simultaneity. In short, the hatchings follow upon one +another, I will not say haphazard--for each of them has its appointed +place in time, determined by impenetrable causes--but at any rate +contrary to our calculations, based on this or the other +consideration. + +Had we not been deceived by our too shallow logic, we might have +foreseen this result. The eggs are laid in their respective cells at +intervals of a few days, of a few hours. How can this slight +difference in age affect the total evolution, which lasts a year? +Mathematical accuracy has nothing to do with the case. Each germ, +each grub has its individual energy, determined we know not how and +varying in each germ or grub. This excess of vitality belongs to the +egg before it leaves the ovary. Might it not, at the moment of +hatching, be the cause why this or that larva takes precedence of its +elders or its juniors, chronology being altogether a secondary +consideration? When the hen sits upon her eggs, is the oldest always +the first to hatch? In the same way, the oldest larva, lodged in the +bottom storey, need not necessarily reach the perfect state first. + +A second argument, had we reflected more deeply on the matter, would +have shaken our faith in any strict mathematical sequence. The same +brood forming the string of cocoons in a bramble-stem contains both +males and females; and the two sexes are divided in the series +indiscriminately. Now it is the rule among the Bees for the males to +issue from the cocoon a little earlier than the females. In the case +of the Three-pronged Osmia, the male has about a week's start. +Consequently, in a populous gallery, there is always a certain number +of males, who are hatched seven or eight days before the females and +who are distributed here and there over the series. This would be +enough to make any regular hatching-sequence impossible in either +direction. + +These surmises accord with the facts: the chronological sequence of +the cells tells us nothing about the chronological sequence of the +hatchings, which take place without any definite order. There is, +therefore, no surrender of rights of primogeniture, as Leon Dufour +thought: each insect, regardless of the others, bursts its cocoon +when its time comes; and this time is determined by causes which +escape our notice and which, no doubt, depend upon the potentialities +of the egg itself. It is the case with the other bramble-dwellers +which I have subjected to the same test (Osmia detrita, Anthidium +scapulare, Solenius vagus, etc.); and it must also be the case with +Odynerus rubicola: so the most striking analogies inform us. +Therefore the singular exception which made such an impression on +Dufour's mind is a sheer logical illusion. + +An error removed is tantamount to a truth gained; and yet, if it were +to end here, the result of my experiment would possess but slight +value. After destruction, let us turn to construction; and perhaps we +shall find the wherewithal to compensate us for an illusion lost. Let +us begin by watching the exit. + +The first Osmia to leave her cocoon, no matter what place she +occupies in the series, forthwith attacks the ceiling separating her +from the floor above. She cuts a fairly clean hole in it, shaped like +a truncate cone, having its larger base on the side where the Bee is +and its smaller base opposite. This conformation of the exit-door is +a characteristic of the work. When the insect tries to attack the +diaphragm, it first digs more or less at random; then, as the boring +progresses, the action is concentrated upon an area which narrows +until it presents no more than just the necessary passage. Nor is the +cone-shaped aperture special to the Osmia: I have seen it made by the +other bramble-dwellers through my thick disks of sorghum-pith. Under +natural conditions, the partitions, which, for that matter, are very +thin, are destroyed absolutely, for the contraction of the cell at +the top leaves barely the width which the insect needs. The truncate, +cone-shaped breach has often been of great use to me. Its wide base +made it possible for me, without being present at the work, to judge +which of the two neighbouring Osmiae had pierced the partition; it +told me the direction of a nocturnal migration which I had been +unable to witness. + +The first-hatched Osmia, wherever she may be, has made a hole in her +ceiling. She is now in the presence of the next cocoon, with her head +at the opening of the hole. In front of her sister's cradle, she +usually stops, consumed with shyness; she draws back into her cell, +flounders among the shreds of the cocoon and the wreckage of the +ruined ceiling; she waits a day, two days, three days, more if +necessary. Should impatience gain the upper hand, she tries to slip +between the wall of the tunnel and the cocoon that blocks the way. +She even undertakes the laborious work of gnawing at the wall, so as +to widen the interval, if possible. We find these attempts, in the +shaft of a bramble, at places where the pith is removed down to the +very wood, where the wood itself is gnawed to some depth. I need +hardly say that, although these lateral inroads are perceptible after +the event, they escape the eye at the moment when they are being +made. + +If we would witness them, we must slightly modify the glass +apparatus. I line the inside of the tube with a thick piece of whity- +brown packing-paper, but only over one half of the circumference; the +other half is left bare, so that I may watch the Osmia's attempts. +Well, the captive insect fiercely attacks this lining, which to its +eyes represents the pithy layer of its usual abode; it tears it away +by tiny particles and strives to cut itself a road between the cocoon +and the glass wall. The males, who are a little smaller, have a +better chance of success than the females. Flattening themselves, +making themselves thin, slightly spoiling the shape of the cocoon, +which, however, thanks to its elasticity, soon recovers its first +condition, they slip through the narrow passage and reach the next +cell. The females, when in a hurry to get out, do as much, if they +find the tube at all amenable to the process. But no sooner is the +first partition passed than a second presents itself. This is pierced +in its turn. In the same way will the third be pierced and others +after that, if the insect can manage them, as long as its strength +holds out. Too weak for these repeated borings, the males do not go +far through my thick plugs. If they contrive to cut through the +first, it is as much as they can do; and, even so, they are far from +always succeeding. But, in the conditions presented by the native +stalk, they have only feeble tissues to overcome; and then, slipping, +as I have said, between the cocoon and the wall, which is slightly +worn owing to the circumstances described, they are able to pass +through the remaining occupied chambers and to reach the outside +first, whatever their original place in the stack of cells. It is +just possible that their early eclosion forces this method of exit +upon them, a method which, though often attempted, does not always +succeed. The females, furnished with stronger tools, make greater +progress in my tubes. I see some who pierce three or four partitions, +one after the other, and are so many stages ahead before those whom +they have left behind are even hatched. While they are engaged in +this long and toilsome operation, others, nearer to the orifice, have +cleared a passage whereof those from a distance will avail +themselves. In this way, it may happen that, when the width of the +tube permits, an Osmia in a back row will nevertheless be one of the +first to emerge. + +In the bramble-stem, which is of exactly the same diameter as the +cocoon, this escape by the side of the column appears hardly +practicable, except to a few males; and even these have to find a +wall which has so much pith that by removing it they can effect a +passage. Let us then imagine a tube so narrow as to prevent any exit +save in the natural sequence of the cells. What will happen? A very +simple thing. The newly-hatched Osmia, after perforating his +partition, finds himself faced with an unbroken cocoon that obstructs +the road. He makes a few attempts upon the sides and, realizing his +impotence, retires into his cell, where he waits for days and days, +until his neighbour bursts her cocoon in her turn. His patience is +inexhaustible. However, it is not put to an over long test, for +within a week, more or less, the whole string of females is hatched. + +When two neighbouring Osmiae are released at the same time, mutual +visits are paid through the aperture between the two rooms: the one +above goes down to the floor below; the one below goes up to the +floor above; sometimes both of them are in the same cell together. +Might not this intercourse tend to cheer them and encourage them to +patience? Meanwhile, slowly, doors are opening here and there through +the separating walls; the road is cleared by sections; and a moment +arrives when the leader of the file walks out. The others follow, if +ready; but there are always laggards who keep the rear-ranks waiting +until they are gone. + +To sum up, first, the hatching of the larvae takes place without any +order; secondly, the exodus proceeds regularly from summit to base, +but only in consequence of the insect's inability to move forward so +long as the upper cells are not vacated. We have here not an +exceptional evolution, in the inverse ratio to age, but the simple +impossibility of emerging otherwise. Should a chance occur of going +out before its turn, the insect does not fail to seize it, as we can +see by the lateral movements which send the impatient ones a few +ranks ahead and even release the more favoured altogether. The only +remarkable thing that I perceive is the scrupulous respect shown to +the as yet unopened neighbouring cocoon. However eager to come out, +the Osmia is most careful not to touch it with his mandibles: it is +taboo. He will demolish the partition, he will gnaw the side-wall +fiercely, even though there be nothing left but wood, he will reduce +everything around him to dust; but touch a cocoon that obstructs his +way? Never! He will not make himself an outlet by breaking up his +sisters' cradles. + +It may happen that the Osmia's patience is in vain and that the +barricade that blocks the way never disappears at all. Sometimes, the +egg in a cell does not mature; and the unconsumed provisions dry up +and become a compact, sticky, mildewed plug, through which the +occupants of the floors below could never clear themselves a passage. +Sometimes, again, a grub dies in its cocoon; and the cradle of the +deceased, now turned into a coffin, forms an everlasting obstacle. +How shall the insect cope with such grave circumstances? + +Among the many bramble-stumps which I have collected, some few have +presented a remarkable peculiarity. In addition to the orifice at the +top, they had at the side one and sometimes two round apertures that +looked as though they had been punched out with an instrument. On +opening these stalks, which were old, deserted nests, I discovered +the cause of these very exceptional windows. Above each of them was a +cell full of mouldy honey. The egg had perished and the provisions +remained untouched: hence the impossibility of getting out by the +ordinary road. Walled in by the unsurmountable obstacle, the Osmia on +the floor below had contrived an outlet through the side of the +shaft; and those in the lower storeys had benefited by this ingenious +innovation. The usual door being inaccessible, a side-window had been +opened by means of the insect's jaws. The cocoons, torn, but still in +position in the lower rooms, left no doubt as to this eccentric mode +of exit. The same fact, moreover, was repeated, in several bramble- +stumps, in the case of Osmia tridentata; it was likewise repeated in +the case of Anthidium scapulare. The observation was worth confirming +by experiment. + +I select a bramble-stem with the thinnest rind possible, so as to +facilitate the Osmiae's work. I split it in half, thus obtaining a +smooth-sided trough which will enable me to judge better of future +exits. The cocoons are next laid out in one of the troughs. I +separate them with disks of sorghum, covering both surfaces of the +disk with a generous layer of sealing-wax, a material which the +Osmia's mandibles are not able to attack. The two troughs are then +placed together and fastened. A little putty does away with the joint +and prevents the least ray of light from penetrating. Lastly, the +apparatus is hung up perpendicularly, with the cocoons' heads up. We +have now only to wait. None of the Osmiae can get out in the usual +manner, because each of them is confined between two partitions +coated with sealing-wax. There is but one resource left to them if +they would emerge into the light of day, that is, for each of them to +open a side-window, provided always that they possess the instinct +and the power to do so. + +In July, the result is as follows: of twenty Osmiae thus immured, six +succeed in boring a round hole through the wall and making their way +out; the others perish in their cells, without managing to release +themselves. But, when I open the cylinder, when I separate the two +wooden troughs, I realize that all have attempted to escape through +the side, for the wall of each cell bears traces of gnawing +concentrated upon one spot. All, therefore, have acted in the same +way as their more fortunate sisters; they did not succeed, because +their strength failed them. Lastly, in my glass tubes, part-lined +with a thick piece of packing-paper, I often see attempts at making a +window in the side of the cell: the paper is pierced right through +with a round hole. + +This then is yet another result which I am glad to record in the +history of the bramble-dwellers. When the Osmia, the Anthidium and +probably others are unable to emerge through the customary outlet, +they take an heroic decision and perforate the side of the shaft. It +is the last resource, resolved upon after other methods have been +tried in vain. The brave, the strong succeed; the weak perish in the +attempt. + +Supposing that all the Osmiae possessed the necessary strength of jaw +as well as the instinct for this sideward boring, it is clear that +egress from each cell through a special window would be much more +advantageous than egress through the common door. The Bee could +attend to his release as soon as he was hatched, instead of +postponing it until after the emancipation of those who come before +him; he would thus escape long waits, which too often prove fatal. In +point of fact, it is no uncommon thing to find bramble-stalks in +which several Osmiae have died in their cells, because the upper +storeys were not vacated in time. Yes, there would be a precious +advantage in that lateral opening, which would not leave each +occupant at the mercy of his environment: many die that would not +die. All the Osmiae, when compelled by circumstances, resort to this +supreme method; all have the instinct for lateral boring; but very +few are able to carry the work through. Only the favourites of fate +succeed, those more generously endowed with strength and +perseverance. + +If the famous law of natural selection, which is said to govern and +transform the world, had any sure foundation; if really the fittest +removed the less fit from the scene; if the future were to the +strongest, to the most industrious, surely the race of Osmiae, which +has been perforating bramble-stumps for ages, should by this time +have allowed its weaker members, who go on obstinately using the +common outlet, to die out and should have replaced them, down to the +very last one, by the stalwart drillers of side-openings. There is an +opportunity here for immense progress; the insect is on the verge of +it and is unable to cross the narrow intervening line. Selection has +had ample time to make its choice; and yet, though there be a few +successes, the failures exceed them in very large measure. The race +of the strong has not abolished the race of the weak: it remains +inferior in numbers, as doubtless it has been since all time. The law +of natural selection impresses me with the vastness of its scope; +but, whenever I try to apply it to actual facts, it leaves me +whirling in space, with nothing to help me to interpret realities. It +is magnificent in theory, but it is a mere gas-bubble in the face of +existing conditions. It is majestic, but sterile. Then where is the +answer to the riddle of the world? Who knows? Who will ever know? + +Let us waste no more time in this darkness, which idle theorizing +will not dispel; let us return to facts, humble facts, the only +ground that does not give way under our feet. The Osmia respects her +neighbour's cocoon; and her scruples are so great that, after vainly +trying to slip between that cocoon and the wall, or else to open a +lateral outlet, she lets herself die in her cell rather than effect +an egress by forcing her way through the occupied cells. When the +cocoon that blocks the way contains a dead instead of a live grub, +will the result be the same? + +In my glass tubes, I let Osmia-cocoons containing a live grub +alternate with Osmia-cocoons in which the grub has been asphyxiated +by the fumes of sulphocarbonic acid. As usual, the storeys are +separated by disks of sorghum. The anchorites, when hatched, do not +hesitate long. Once the partition is pierced, they attack the dead +cocoons, go right through them, reducing the dead grub, now dry and +shrivelled, to dust, and at last emerge, after wrecking everything in +their path. The dead cocoons, therefore, are not spared; they are +treated as would be any other obstacle capable of attack by the +mandibles. The Osmia looks upon them as a mere barricade to be +ruthlessly overturned. How is she apprised that the cocoon, which has +undergone no outward change, contains a dead and not a live grub? It +is certainly not by sight. Can it be by sense of smell? I am always a +little suspicious of that sense of smell of which we do not know the +seat and which we introduce on the slightest provocation as a +convenient explanation of that which may transcend our explanatory +powers. + +My next test is made with a string of live cocoons. Of course, I +cannot take all these from the same species, for then the experiment +would not differ from the one which we have already witnessed; I take +them from two different species which leave their bramble-stem at +separate periods. Moreover, these cocoons must have nearly the same +diameter to allow of their being stacked in a tube without leaving an +empty space between them and the wall. The two species adopted are +Solenius vagus, which quits the bramble at the end of June, and Osmia +detrita, which comes a little earlier, in the first fortnight of the +same month. I therefore alternate Osmia-cocoons and Solenius-cocoons, +with the latter at the top of the series, either in glass tubes or +between two bramble-troughs joined into a cylinder. + +The result of this promiscuity is striking. The Osmiae, which mature +earlier, emerge; and the Solenius-cocoons, as well as their +inhabitants, which by this time have reached the perfect stage, are +reduced to shreds, to dust, wherein it is impossible for me to +recognize a vestige, save perhaps here and there a head, of the +exterminated unfortunates. The Osmia, therefore, has not respected +the live cocoons of a foreign species: she has passed out over the +bodies of the intervening Solenii. Did I say passed over their +bodies? She has passed through them, crunched the laggards between +her jaws, treated them as cavalierly as she treats my disks. And yet +those barricades were alive. No matter: when her hour came, the Osmia +went ahead, destroying everything upon her road. Here, at any rate, +is a law on which we can rely: the supreme indifference of the animal +to all that does not form part of itself and its race. + +And what of the sense of smell, distinguishing the dead from the +living? Here, all are alive; and the Bee pierces her way as through a +row of corpses. If I am told that the smell of the Solenii may differ +from that of the Osmiae, I shall reply that such extreme subtlety in +the insect's olfactory apparatus seems to me a rather far-fetched +supposition. Then what is my explanation of the two facts? The +explanation? I have none to give! I am quite content to know that I +do not know, which at least spares me many vain lucubrations. And so +I do not know how the Osmia, in the dense darkness of her tunnel, +distinguishes between a live cocoon and a dead cocoon of the same +species; and I know just as little how she succeeds in recognizing a +strange cocoon. Ah, how clearly this confession of ignorance proves +that I am behind the times! I am deliberately missing a glorious +opportunity of stringing big words together and arriving at nothing. + +The bramble-stump is perpendicular, or nearly so; its opening is at +the top. This is the rule under natural conditions. My artifices are +able to alter that state of things; I can place the tube vertically +or horizontally; I can turn its one orifice either up or down; +lastly, I can leave the channel open at both ends, which will give +two outlets. What will happen under these several conditions? That is +what we shall examine with the Three-pronged Osmia. + +The tube is hung perpendicularly, but closed at the top and open at +the bottom; in fact, it represents a bramble-stump turned upside +down. To vary and complicate the experiment, the strings of cocoons +are arranged differently in different tubes. In some of them, the +heads of the cocoons are turned downwards, towards the opening; in +others, they are turned upwards, towards the closed end; in others +again, the cocoons alternate in direction, that is to say, they are +placed head to head and rear to rear, turn and turn about. I need not +say that the separating floors are of sorghum. + +The result is identical in all these tubes. If the Osmiae have their +heads pointing upwards, they attack the partition above them, as +happens under normal conditions; if their heads point downwards, they +turn round in their cells and set to work as usual. In short, the +general outward trend is towards the top, in whatever position the +cocoon be placed. + +We here see manifestly at work the influence of gravity, which warns +the insect of its reversed position and makes it turn round, even as +it would warn us if we ourselves happened to be hanging head +downwards. In natural conditions, the insect has but to follow the +counsels of gravity, which tells it to dig upwards, and it will +infallibly reach the exit-door situated at the upper end. But, in my +apparatus, these same counsels betray it: it goes towards the top, +where there is no outlet. Thus misled by my artifices, the Osmiae +perish, heaped up on the higher floors and buried in the ruins. + +It nevertheless happens that attempts are made to clear a road +downwards. But it is rare for the work to lead to anything in this +direction, especially in the case of the middle or upper cells. The +insect is little inclined for this progress, the opposite to that to +which it is accustomed; besides, a serious difficulty arises in the +course of this reversed boring. As the Bee flings the excavated +materials behind her, these fall back of their own weight under her +mandibles; the clearance has to be begun anew. Exhausted by her +Sisyphean task, distrustful of this new and unfamiliar method, the +Osmia resigns herself and expires in her cell. I am bound to add, +however, that the Osmiae in the lower storeys, those nearest the +exit--sometimes one, sometimes two or three--do succeed in escaping. +In that case, they unhesitatingly attack the partitions below them, +while their companions, who form the great majority, persist and +perish in the upper cells. + +It was easy to repeat the experiment without changing anything in the +natural conditions, except the direction of the cocoons: all that I +had to do was to hang up some bramble-stumps as I found them, +vertically, but with the opening downwards. Out of two stalks thus +arranged and peopled with Osmiae, not one of the insects succeeded in +emerging. All the Bees died in the shaft, some turned upwards, others +downwards. On the other hand, three stems occupied by Anthidia +discharged their population safe and sound. The outgoing was effected +at the bottom, from first to last, without the least impediment. Must +we take it that the two sorts of Bees are not equally sensitive to +the influences of gravity? Can the Anthidium, built to pass through +the difficult obstacle of her cotton wallets, be better-adapted than +the Osmia to make her way through the wreckage that keeps falling +under the worker's feet; or, rather, may not this very cotton-waste +put a stop to these cataracts of rubbish which must naturally drive +the insect back? This is all quite possible; but I can say nothing +for certain. + +Let us now experiment with vertical tubes open at both ends. The +arrangements, save for the upper orifice, are the same as before. The +cocoons, in some of the tubes, have their heads turned down; others, +up; in others again, their positions alternate. The result is similar +to what we have seen above. A few Osmiae, those nearest the bottom +orifice, take the lower road, whatever the direction first occupied +by the cocoon; the others, composing by far the larger number, take +the higher road, even when the cocoon is placed upside down. As both +doors are free, the outgoing is effected at either end with success. + +What are we to conclude from all these experiments? First, that +gravity guides the insect towards the top, where the natural door is, +and makes it turn in its cell when the cocoon has been reversed. +Secondly, I seem to suspect an atmospheric influence and, in any +case, some second cause that sends the insect to the outlet. Let us +admit that this cause is the proximity of the outer air acting upon +the anchorite through the partitions. + +The animal then is subject, on the one hand, to the promptings of +gravity, and this to an equal degree for all, whatever the storey +inhabited. Gravity is the common guide of the whole series from base +to top. But those in the lower boxes have a second guide, when the +bottom end is open. This is the stimulus of the adjacent air, a more +powerful stimulus than that of gravity. The access of the air from +without is very slight, because of the partitions; while it can be +felt in the nethermost cells, it must decrease rapidly as the storeys +ascend. Wherefore the bottom insects, very few in number, obeying the +preponderant influence, that of the atmosphere, make for the lower +outlet and reverse, if necessary, their original position; those +above, on the contrary, who form the great majority, being guided +only by gravity when the upper end is closed, make for that upper +end. It goes without saying that, if the upper end be open at the +same time as the other, the occupants of the top storeys will have a +double incentive to take the ascending path, though this will not +prevent the dwellers on the lower floors from obeying, by preference, +the call of the adjacent air and adopting the downward road. + +I have one means left whereby to judge of the value of my +explanation, namely, to experiment with tubes open at both ends and +lying horizontally. The horizontal position has a twofold advantage. +In the first place, it removes the insect from the influence of +gravity, inasmuch as it leaves it indifferent to the direction to be +taken, the right or the left. In the second place, it does away with +the descent of the rubbish which, falling under the worker's feet +when the boring is done from below, sooner or later discourages her +and makes her abandon her enterprise. + +There are a few precautions to be observed for the successful conduct +of the experiment; I recommend them to any one who might care to make +the attempt. It is even advisable to remember them in the case of the +tests which I have already described. The males, those puny +creatures, not built for work, are sorry labourers when confronted +with my stout disks. Most of them perish miserably in their glass +cells, without succeeding in piercing their partitions right through. +Moreover, instinct has been less generous to them than to the +females. Their corpses, interspersed here and there in the series of +the cells, are disturbing causes, which it is wise to eliminate. I +therefore choose the larger, more powerful-looking cocoons. These, +except for an occasional unavoidable error, belong to females. I pack +them in tubes, sometimes varying their position in every way, +sometimes giving them all a like arrangement. It does not matter +whether the whole series comes from one and the same bramble-stump or +from several: we are free to choose where we please; the result will +not be altered. + +The first time that I prepared one of these horizontal tubes open at +both ends, I was greatly struck by what happened. The series +consisted of ten cocoons. It was divided into two equal batches. The +five on the left went out on the left, the five on the right went out +on the right, reversing, when necessary, their original direction in +the cell. It was very remarkable from the point of view of symmetry; +moreover, it was a very unlikely arrangement among the total number +of possible arrangements, as mathematics will show us. + +Let us take n to represent the number of Osmiae. Each of them, once +gravity ceases to interfere and leaves the insect indifferent to +either end of the tube, is capable of two positions, according as she +chooses the exit on the right or on the left. With each of the two +positions of this first Osmia can be combined each of the two +positions of the second, giving us, in all, 2 x 2 = (2 squared) +arrangements. Each of these (2 squared) arrangements can be combined, +in its turn, with each of the two positions of the third Osmia. We +thus obtain 2 x 2 x 2 = (2 cubed) arrangements with three Osmiae; and +so on, each additional insect multiplying the previous result by the +factor 2. With n Osmiae, therefore, the total number of arrangements +is (2 to the power n.) + +But note that these arrangements are symmetrical, two by two: a given +arrangement towards the right corresponds with a similar arrangement +towards the left; and this symmetry implies equality, for, in the +problem in hand, it is a matter of indifference whether a fixed +arrangement correspond with the right or left of the tube. The +previous number, therefore, must be divided by 2. Thus, n Osmiae, +according as each of them turns her head to the right or left in my +horizontal tube, are able to adopt (2 to the power n - 1) +arrangements. If n = 10, as in my first experiment, the number of +arrangements becomes (2 to the power 9) = 512. + +Consequently, out of 512 ways which my ten insects can adopt for +their outgoing position, there resulted one of those in which the +symmetry was most striking. And observe that this was not an effect +obtained by repeated attempts, by haphazard experiments. Each Osmia +in the left half had bored to the left, without touching the +partition on the right; each Osmia in the right half had bored to the +right, without touching the partition on the left. The shape of the +orifices and the surface condition of the partition showed this, if +proof were necessary. There had been a spontaneous decision, one half +in favour of the left, one half in favour of the right. + +The arrangement presents another merit, one superior to that of +symmetry: it has the merit of corresponding with the minimum +expenditure of force. To admit of the exit of the whole series, if +the string consists of n cells, there are originally n partitions to +be perforated. There might even be one more, owing to a complication +which I disregard. There are, I say, at least n partitions to be +perforated. Whether each Osmia pierces her own, or whether the same +Osmia pierces several, thus relieving her neighbours, does not matter +to us: the sum-total of the force expended by the string of Bees will +be in proportion to the number of those partitions, in whatever +manner the exit be effected. + +But there is another task which we must take seriously into +consideration, because it is often more troublesome than the boring +of the partition: I mean the work of clearing a road through the +wreckage. Let us suppose the partitions pierced and the several +chambers blocked by the resulting rubbish and by that rubbish only, +since the horizontal position precludes any mixing of the contents of +different chambers. To open a passage for itself through these +rubbish-heaps, each insect will have the smallest effort to make if +it passes through the smallest possible number of cells, in short, if +it makes for the opening nearest to it. These smallest individual +efforts amount, in the aggregate, to the smallest total effort. +Therefore, by proceeding as they did in my experiment, the Osmiae +effect their exit with the least expenditure of energy. It is curious +to see an insect apply the 'principle of least action,' so often +postulated in mechanics. + +An arrangement which satisfies this principle, which conforms to the +law of symmetry and which possesses but one chance in 512, is +certainly no fortuitous result. It is determined by a cause; and, as +this cause acts invariably, the same arrangement must be reproduced +if I renew the experiment. I renewed it, therefore, in the years that +followed, with as many appliances as I could find bramble-stumps; +and, at each new test, I saw once more what I had seen with such +interest on the first occasion. If the number be even--and my column +at that time consisted usually of ten--one half goes out on the +right, the other on the left. If the number be odd--eleven, for +instance--the Osmia in the middle goes out indiscriminately by the +right or left exit. As the number of cells to be traversed is the +same on both sides, her expenditure of energy does not vary with the +direction of the exit; and the principle of least action is still +observed. + +It was important to discover if the Three-pronged Osmia shared her +capacity, in the first place, with the other bramble-dwellers and, in +the second, with Bees differently housed, but also destined +laboriously to cut a new road for themselves when the hour comes to +quit the nest. Well, apart from a few irregularities, due either to +cocoons whose larva perished in my tubes before developing, or to +those inexperienced workers, the males, the result was the same in +the case of Anthidium scapulare. The insects divided themselves into +two equal batches, one going to the right, the other to the left. +Tripoxylon figulus left me undecided. This feeble insect is not +capable of perforating my partitions; it nibbles at them a little; +and I had to judge the direction from the marks of its mandibles. +These marks, which are not always very plain, do not yet allow me to +pronounce an opinion. Solenius vagus, who is a skilful borer, behaved +differently from the Osmia. In a column of ten, the whole exodus was +made in one direction. + +On the other hand, I tested the Mason-bee of the Sheds, who, when +emerging under natural conditions, has only to pierce her cement +ceiling and is not confronted with a series of cells. Though a +stranger to the environment which I created for her, she gave me a +most positive answer. Of a column of ten laid in a horizontal tube +open at both ends, five made their way to the right and five to the +left. Dioxys cincta, a parasite in the buildings of both species of +Mason-bees, the Chalicodoma of the Sheds and the Chalicodoma of the +Walls (Cf. "The Mason-bees" by J. Henri Fabre, translated by +Alexander Teixeira de Mattos: passim.--Translator's Note.), provided +me with no precise result. The Leaf-cutting Bee (Megachile apicalis, +SPIN. (Cf. Chapter 8 of the present volume.--Translator's Note.)), +who builds her leafy cups in the old cells of the Chalicodoma of the +Walls, acts like the Solenius and directs her whole column towards +the same outlet. + +Incomplete as it is, this symmetry shows us how unwise it were to +generalize from the conclusions to which the Three-pronged Osmia +leads us. Whereas some Bees, such as the Anthidium and the +Chalicodoma, share the Osmia's talent for using the twofold exit, +others, such as the Solenius and the Leaf-cutter, behave like a flock +of sheep and follow the first that goes out. The entomological world +is not all of a piece; its gifts are very various: what one is +capable of doing another cannot do; and penetrating indeed would be +the eyes that saw the causes of these differences. Be this as it may, +increased research will certainly show us a larger number of species +qualified to use the double outlet. For the moment, we know three; +and that is enough for our purpose. + +I will add that, when the horizontal tube has one of its ends closed, +the whole string of Osmiae makes for the open end, turning round to +do so, if need be. + +Now that the facts are set forth, let us, if possible, trace the +cause. In a horizontal tube, gravity no longer acts to determine the +direction which the insect will take. Is it to attack the partition +on the right or that on the left? How shall it decide? The more I +look into the matter, the more do my suspicions fall upon the +atmospheric influence which is felt through the two open ends. Of +what does this influence consist? Is it an effect of pressure, of +hygrometry, of electrical conditions, of properties that escape our +coarser physical attunement? He were a bold man who should undertake +to decide. Are not we ourselves, when the weather is about to alter, +subject to subtle impressions, to sensations which we are unable to +explain? And yet this vague sensitiveness to atmospheric changes +would not be of much help to us in circumstances similar to those of +my anchorites. Imagine ourselves in the darkness and the silence of a +prison-cell, preceded and followed by other similar cells. We possess +implements wherewith to pierce the walls; but where are we to strike +to reach the final outlet and to reach it with the least delay? +Atmospheric influence would certainly never guide us. + +And yet it guides the insect. Feeble though it be, through the +multiplicity of partitions, it is exercised on one side more than on +the other, because the obstacles are fewer; and the insect, sensible +to the difference between those two uncertainties, unhesitatingly +attacks the partition which is nearer to the open air. Thus is +decided the division of the column into two converse sections, which +accomplish the total liberation with the least aggregate of work. In +short, the Osmia and her rivals 'feel' the free space. This is yet +one more sensory faculty which evolution might well have left us, for +our greater advantage. As it has not done so, are we then really, as +many contend, the highest expression of the progress accomplished, +throughout the ages, by the first atom of glair expanded into a cell? + + +CHAPTER 2. THE OSMIAE. + +February has its sunny days, heralding spring, to which rude winter +will reluctantly yield place. In snug corners, among the rocks, the +great spurge of our district, the characias of the Greeks, the jusclo +of the Provencals, begins to lift its drooping inflorescence and +discreetly opens a few sombre flowers. Here the first Midges of the +year will come to slake their thirst. By the time that the tip of the +stalks reaches the perpendicular, the worst of the cold weather will +be over. + +Another eager one, the almond-tree, risking the loss of its fruit, +hastens to echo these preludes to the festival of the sun, preludes +which are too often treacherous. A few days of soft skies and it +becomes a glorious dome of white flowers, each twinkling with a +roseate eye. The country, which still lacks green, seems dotted +everywhere with white-satin pavilions. 'Twould be a callous heart +indeed that could resist the magic of this awakening. + +The insect nation is represented at these rites by a few of its more +zealous members. There is first of all the Honey-bee, the sworn enemy +of strikes, who profits by the least lull of winter to find out if +some rosemary is not beginning to open somewhere near the hive. The +droning of the busy swarm fills the flowery vault, while a snow of +petals falls softly to the foot of the tree. + +Together with the population of harvesters there mingles another, +less numerous, of mere drinkers, whose nesting-time has not yet +begun. This is the colony of the Osmiae, with their copper-coloured +skin and bright-red fleece. Two species have come hurrying up to take +part in the joys of the almond-tree: first, the Horned Osmia, clad in +black velvet on the head and breast and in red velvet on the abdomen; +and, a little later, the Three-horned Osmia, whose livery must be red +and red only. These are the first delegates despatched by the pollen- +gleaners to ascertain the state of the season and attend the festival +of the early blooms. 'Tis but a moment since they burst their cocoon, +the winter abode: they have left their retreats in the crevices of +the old walls; should the north wind blow and set the almond-tree +shivering, they will hasten to return to them. Hail to you, O my dear +Osmiae, who yearly, from the far end of the harmas (The piece of +waste ground in which the author studied his insects in their natural +state. Cf. "The Life of the Fly" by J. Henri Fabre, translated by +Alexander Teixeira de Mattos: chapter 1.--Translator's Note.), +opposite snow-capped Ventoux (A mountain in the Provencal Alps, near +Carpentras and Serignan, 6,271 feet.--Translator's Note.), bring me +the first tidings of the awakening of the insect world! I am one of +your friends; let us talk about you a little. + +Most of the Osmiae of my region have none of the industry of their +kinswomen of the brambles, that is to say, they do not themselves +prepare the dwelling destined for the laying. They want ready-made +lodgings, such as the old cells and old galleries of Anthophorae and +Chalicodomae. If these favourite haunts are lacking, then a hiding- +place in the wall, a round hole in some bit of wood, the tube of a +reed, the spiral of a dead Snail under a heap of stones are adopted, +according to the tastes of the several species. The retreat selected +is divided into chambers by partition-walls, after which the entrance +to the dwelling receives a massive seal. That is the sum-total of the +building done. + +For this plasterer's rather than mason's work, the Horned and the +Three-horned Osmia employ soft earth. This material is different from +the Mason-bee's cement, which will withstand wind and weather for +many years on an exposed pebble; it is a sort of dried mud, which +turns to pap on the addition of a drop of water. The Mason-bee +gathers her cementing-dust in the most frequented and driest portions +of the road; she wets it with a saliva which, in drying, gives it the +consistency of stone. The two Osmiae who are the almond-tree's early +visitors are no chemists: they know nothing of the making and mixing +of hydraulic mortar; they limit themselves to gathering natural +soaked earth, mud in short, which they allow to dry without any +special preparation on their part; and so they need deep and well- +sheltered retreats, into which the rain cannot penetrate, or the work +would fall to pieces. + +While exploiting, in friendly rivalry with the Three-horned Osmia, +the galleries which the Mason-bee of the Sheds good-naturedly +surrenders to both, Latreille's Osmia uses different materials for +her partitions and her doors. She chews the leaves of some +mucilaginous plant, some mallow perhaps, and then prepares a sort of +green putty with which she builds her partitions and finally closes +the entrance to the dwelling. When she settles in the spacious cells +of the Masked Anthophora (Anthophora personata, ILLIG.), the entrance +to the gallery, which is wide enough to admit one's finger, is closed +with a voluminous plug of this vegetable paste. On the earthy banks, +hardened by the sun, the home is then betrayed by the gaudy colour of +the lid. It is as though the authorities had closed the door and +affixed to it their great seals of green wax. + +So far then as their building-materials are concerned, the Osmiae +whom I have been able to observe are divided into two classes: one +building compartments with mud, the other with a green-tinted +vegetable putty. The first section includes the Horned Osmia and the +Three-horned Osmia, both so remarkable for the horny tubercles on +their faces. + +The great reed of the south, the Arundo donax, is often used, in the +country, for rough garden-shelters against the mistral or just for +fences. These reeds, the ends of which are chopped off to make them +all the same length, are planted perpendicularly in the earth. I have +often explored them in the hope of finding Osmia-nests. My search has +very seldom succeeded. The failure is easily explained. The +partitions and the closing-plug of the Horned and of the Three-horned +Osmia are made, as we have seen, of a sort of mud which water +instantly reduces to pap. With the upright position of the reeds, the +stopper of the opening would receive the rain and would become +diluted; the ceilings of the storeys would fall in and the family +would perish by drowning. Therefore the Osmia, who knew of these +drawbacks before I did, refuses the reeds when they are placed +perpendicularly. + +The same reed is used for a second purpose. We make canisses of it, +that is to say, hurdles, which, in spring, serve for the rearing of +silk-worms and, in autumn, for the drying of figs. At the end of +April and during May, which is the time when the Osmiae work, the +canisses are indoors, in the silk-worm nurseries, where the Bee +cannot take possession of them; in autumn, they are outside, exposing +their layers of figs and peeled peaches to the sun; but by that time +the Osmiae have long disappeared. If, however, during the spring, an +old, disused hurdle is left out of doors, in a horizontal position, +the Three-horned Osmia often takes possession of it and makes use of +the two ends, where the reeds lie truncated and open. + +There are other quarters that suit the Three-horned Osmia, who is not +particular, it seems to me, and will make shift with any hiding- +place, so long as it has the requisite conditions of diameter, +solidity, sanitation and kindly darkness. The most original dwellings +that I know her to occupy are disused Snail-shells, especially the +house of the Common Snail (Helix aspersa). Let us go to the slope of +the hills thick with olive-trees and inspect the little supporting- +walls which are built of dry stones and face the south. In the +crevices of this insecure masonry, we shall reap a harvest of old +Snail-shells, plugged with earth right up to the orifice. The family +of the Three-horned Osmia is settled in the spiral of those shells, +which is subdivided into chambers by mud partitions. + +Let us inspect the stone-heaps, especially those which come from the +quarry-works. Here we often find the Field-mouse sitting on a grass +mattress, nibbling acorns, almonds, olive-stones and apricot-stones. +The Rodent varies his diet: to oily and farinaceous foods he adds the +Snail. When he is gone, he has left behind him, under the overhanging +stones, mixed up with the remains of other victuals, an assortment of +empty shells, sometimes plentiful enough to remind me of the heap of +Snails which, cooked with spinach and eaten country-fashion on +Christmas Eve, are flung away next day by the housewife. This gives +the Three-horned Osmia a handsome collection of tenements; and she +does not fail to profit by them. Then again, even if the Field- +mouse's conchological museum be lacking, the same broken stones serve +as a refuge for Garden-snails who come to live there and end by dying +there. When we see Three-horned Osmiae enter the crevices of old +walls and of stone-heaps, there is no doubt about their occupation: +they are getting free lodgings out of the old Snail-shells of those +labyrinths. + +The Horned Osmia, who is less common, might easily also be less +ingenious, that is to say, less rich in varieties of houses. She +seems to scorn empty shells. The only homes that I know her to +inhabit are the reeds of the hurdles and the deserted cells of the +Masked Anthophora. + +All the other Osmiae whose method of nest-building I know work with +green putty, a paste made of some crushed leaf or other; and none of +them, except Latreille's Osmia, is provided with the horned or +tubercled armour of the mud-kneaders. I should like to know what +plants are used in making the putty; probably each species has its +own preferences and its little professional secrets; but hitherto +observation has taught me nothing concerning these details. Whatever +worker prepare it, the putty is very much the same in appearance. +When fresh, it is always a clear dark green. Later, especially in the +parts exposed to the air, it changes, no doubt through fermentation, +to the colour of dead leaves, to brown, to dull-yellow; and the leafy +character of its origin is no longer apparent. But uniformity in the +materials employed must not lead us to believe in uniformity in the +lodging; on the contrary, this lodging varies greatly with the +different species, though there is a marked predilection in favour of +empty shells. Thus Latreille's Osmia, together with the Three-horned +Osmia, uses the spacious structures of the Mason-bee of the Sheds; +she likes the magnificent cells of the Masked Anthophora; and she is +always ready to establish herself in the cylinder of any reed lying +flat on the ground. + +I have already spoken of an Osmia (O. cyanoxantha, PEREZ) who elects +to make her home in the old nests of the Mason-bee of the Pebbles. +(Cf. "The Mason-bees": chapter 10.--Translator's Note.) Her closing- +plug is made of a stout concrete, consisting of fair-sized bits of +gravel sunk in the green paste; but for the inner partitions she +employs only unalloyed putty. As the outer door, situated on the +curve of an unprotected dome, is exposed to the inclemencies of the +weather, the mother has to think of fortifying it. Danger, no doubt, +is the originator of that gritty concrete. + +The Golden Osmia (O. aurulenta, LATR.) absolutely insists on an empty +Snail-shell as her residence. The Brown or Girdled Snail, the Garden +Snail and especially the Common Snail, who has a more spacious +spiral, all scattered at random in the grass, at the foot of the +walls and of the sun-swept rocks, furnish her with her usual +dwelling-house. Her dried putty is a kind of felt full of short white +hairs. It must come from some hairy-leaved plant, one of the +Boragineae perhaps, rich both in mucilage and the necessary bristles. + +The Red Osmia (O. rufo-hirta, LATR.) has a weakness for the Brown +Snail and the Garden Snail, in whose shells I find her taking refuge +in April when the north-wind blows. I am not yet much acquainted with +her work, which should resemble that of the Golden Osmia. + +The Green Osmia (O. viridana, MORAWITZ) takes up her quarters, tiny +creature that she is, in the spiral staircase of Bulimulus radiatus. +It is a very elegant, but very small lodging, to say nothing of the +fact that a considerable portion is taken up with the green-putty +plug. There is just room for two. + +The Andrenoid Osmia (O. andrenoides, LATR.), who looks so curious, +with her naked red abdomen, appears to build her nest in the shell of +the Common Snail, where I discover her refuged. + +The Variegated Osmia (O. versicolor, LATR.) settles in the Garden +Snail's shell, almost right at the bottom of the spiral. + +The Blue Osmia (O. cyanea, KIRB.) seems to me to accept many +different quarters. I have extracted her from old nests of the Mason- +bee of the Pebbles, from the galleries dug in a roadside bank by the +Colletes (A short-tongued Burrowing-bee known also as the Melitta.-- +Translator's Note.) and lastly from the cavities made by some digger +or other in the decayed trunk of a willow-tree. + +Morawitz' Osmia (O. Morawitzi, PEREZ) is not uncommon in the old +nests of the Mason-bee of the Pebbles, but I suspect her of favouring +other lodgings besides. + +The Three-pronged Osmia (O. tridentata, DUF. and PER.) creates a home +of her own, digging herself a channel with her mandibles in dry +bramble and sometimes in danewort. It mixes a few scrapings of +perforated pith with the green paste. Its habits are shared by the +Ragged Osmia (O. detrita, PEREZ) and by the Tiny Osmia (O. parvula, +DUF.) + +The Chalicodoma works in broad daylight, on a tile, on a pebble, on a +branch in the hedge; none of her trade-practises is kept a secret +from the observer's curiosity. The Osmia loves mystery. She wants a +dark retreat, hidden from the eye. I would like, nevertheless, to +watch her in the privacy of her home and to witness her work with the +same facility as if she were nest-building in the open air. Perhaps +there are some interesting characteristics to be picked up in the +depths of her retreats. It remains to be seen whether my wish can be +realized. + +When studying the insect's mental capacity, especially its very +retentive memory for places, I was led to ask myself whether it would +not be possible to make a suitably-chosen Bee build in any place that +I wished, even in my study. And I wanted, for an experiment of this +sort, not an individual but a numerous colony. My preference leant +towards the Three-horned Osmia, who is very plentiful in my +neighbourhood, where, together with Latreille's Osmia, she frequents +in particular the monstrous nests of the Chalicodoma of the Sheds. I +therefore thought out a scheme for making the Three-horned Osmia +accept my study as her settlement and build her nests in glass tubes, +through which I could easily watch the progress. To these crystal +galleries, which might well inspire a certain distrust, were to be +added more natural retreats: reeds of every length and thickness and +disused Chalicodoma-cells taken from among the biggest and the +smallest. A scheme like this sounds mad. I admit it, while mentioning +that perhaps none ever succeeded so well with me. We shall see as +much presently. + +My method is extremely simple. All I ask is that the birth of my +insects, that is to say, their first seeing the light, their emerging +from the cocoon, should take place on the spot where I propose to +make them settle. Here there must be retreats of no matter what +nature, but of a shape similar to that in which the Osmia delights. +The first impressions of sight, which are the most long-lived of any, +shall bring back my insects to the place of their birth. And not only +will the Osmiae return, through the always open windows, but they +will always nidify on the natal spot if they find something like the +necessary conditions. + +And so, all through the winter, I collect Osmia-cocoons, picked up in +the nests of the Mason-bee of the Sheds; I go to Carpentras to glean +a more plentiful supply in the nests of the Hairy-footed Anthophora, +that old acquaintance whose wonderful cities I used to undermine when +I was studying the history of the Oil-beetles. (This study is not yet +translated into English; but cf. "The Life of the Fly": chapters 2 +and 4.--Translator's Note.) Later, at my request, a pupil and +intimate friend of mine, M. Henri Devillario, president of the civil +court at Carpentras, sends me a case of fragments broken off the +banks frequented by the Hairy-footed Anthophora and the Anthophora of +the Walls, useful clods which furnish a handsome adjunct to my +collection. Indeed, at the end, I find myself with handfuls of +cocoons of the Three-horned Osmia. To count them would weary my +patience without serving any particular purpose. + +I spread out my stock in a large open box on a table which receives a +bright diffused light but not the direct rays of the sun. The table +stands between two windows facing south and overlooking the garden. +When the moment of hatching comes, those two windows will always +remain open to give the swarm entire liberty to go in and out as it +pleases. The glass tubes and the reed-stumps are laid here and there, +in fine disorder, close to the heap of cocoons and all in a +horizontal position, for the Osmia will have nothing to do with +upright reeds. The hatching of some of the Osmiae will therefore take +place under cover of the galleries destined to be the building-yard +later; and the site will be all the more deeply impressed on their +memory. When I have made these comprehensive arrangements, there is +nothing more to be done; and I wait patiently for the building-season +to open. + +My Osmiae leave their cocoons in the second half of April. Under the +immediate rays of the sun, in well-sheltered nooks, the hatching +would occur a month earlier, as we can see from the mixed population +of the snowy almond-tree. The constant shade in my study has delayed +the awakening, without, however, making any change in the nesting- +period, which synchronizes with the flowering of the thyme. We now +have, around my working-table, my books, my jars and my various +appliances, a buzzing crowd that goes in and out of the windows at +every moment. I enjoin the household henceforth not to touch a thing +in the insects' laboratory, to do no more sweeping, no more dusting. +They might disturb the swarm and make it think that my hospitality +was not to be trusted. I suspect that the maid, wounded in her self- +esteem at seeing so much dust accumulating in the master's study, did +not always respect my prohibitions and came in stealthily, now and +again, to give a little sweep of the broom. At any rate, I came +across a number of Osmiae who seemed to have been crushed under foot +while taking a sunbath on the floor in front of the window. Perhaps +it was I myself who committed the misdeed in a heedless moment. There +is no great harm done, for the population is a numerous one; and, +notwithstanding those crushed by inadvertence, notwithstanding the +parasites wherewith many of the cocoons are infested, notwithstanding +those who may have come to grief outside or been unable to find their +way back, notwithstanding the deduction of one-half which we must +make for the males: notwithstanding all this, during four or five +weeks I witness the work of a number of Osmiae which is much too +large to allow of my watching their individual operations. I content +myself with a few, whom I mark with different-coloured spots to +distinguish them; and I take no notice of the others, whose finished +work will have my attention later. + +The first to appear are the males. If the sun is bright, they flutter +around the heap of tubes as if to take careful note of the locality; +blows are exchanged and the rival swains indulge in mild skirmishing +on the floor, then shake the dust off their wings and fly away. I +find them, opposite my window, in the refreshment-bar of the lilac- +bush, whose branches bend with the weight of their scented panicles. +Here the Bees get drunk with sunshine and draughts of honey. Those +who have had their fill come home and fly assiduously from tube to +tube, placing their heads in the orifices to see if some female will +at last make up her mind to emerge. + +One does, in point of fact. She is covered with dust and has the +disordered toilet that is inseparable from the hard work of the +deliverance. A lover has seen her, so has a second, likewise a third. +All crowd round her. The lady responds to their advances by clashing +her mandibles, which open and shut rapidly, several times in +succession. The suitors forthwith fall back; and they also, no doubt +to keep up their dignity, execute savage mandibular grimaces. Then +the beauty retires into the arbour and her wooers resume their places +on the threshold. A fresh appearance of the female, who repeats the +play with her jaws; a fresh retreat of the males, who do the best +they can to flourish their own pincers. The Osmiae have a strange way +of declaring their passion: with that fearsome gnashing of their +mandibles, the lovers look as though they meant to devour each other. +It suggests the thumps affected by our yokels in their moments of +gallantry. + +The ingenious idyll is soon over. By turns greeting and greeted with +a clash of jaws, the female leaves her gallery and begins impassively +to polish her wings. The rivals rush forward, hoist themselves on top +of one another and form a pyramid of which each struggles to occupy +the base by toppling over the favoured lover. He, however, is careful +not to let go; he waits for the strife overhead to calm down; and, +when the supernumeraries realize that they are wasting their time and +throw up the game, the couple fly away far from the turbulent rivals. +This is all that I have been able to gather about the Osmia's +nuptials. + +The females, who grow more numerous from day to day, inspect the +premises; they buzz outside the glass galleries and the reed +dwellings; they go in, stay for a while, come out, go in again and +then fly away briskly into the garden. They return, first one, then +another. They halt outside, in the sun, on the shutters fastened back +against the wall; they hover in the window-recess, come inside, go to +the reeds and give a glance at them, only to set off again and to +return soon after. Thus do they learn to know their home, thus do +they fix their birthplace in their memory. The village of our +childhood is always a cherished spot, never to be effaced from our +recollection. The Osmia's life endures for a month; and she acquires +a lasting remembrance of her hamlet in a couple of days. 'Twas there +that she was born; 'twas there that she loved; 'tis there that she +will return. Dulces reminiscitur Argos. +('Now falling by another's wound, his eyes +He casts to heaven, on Argos thinks and dies.' +--"Aeneid," Book 10 Dryden's translation.) + +At last each has made her choice. The work of construction begins; +and my expectations are fulfilled far beyond my wishes. The Osmiae +build nests in all the retreats which I have placed at their +disposal. The glass tubes, which I cover with a sheet of paper to +produce the shade and mystery favourable to concentrated toil, do +wonderfully well. All, from first to last, are occupied. The Osmiae +quarrel for the possession of these crystal palaces, hitherto unknown +to their race. The reeds and the paper tubes likewise do wonderfully. +The number provided is too small; and I hasten to increase it. Snail- +shells are recognized as excellent abodes, though deprived of the +shelter of the stone-heap; old Chalicodoma-nests, down to those of +the Chalicodoma of the Shrubs (Cf. "The Mason-bees": chapters 4 and +10.--Translator's Note.), whose cells are so small, are eagerly +occupied. The late-comers, finding nothing else free, go and settle +in the locks of my table-drawers. There are daring ones who make +their way into half-open boxes containing ends of glass tubes in +which I have stored my most recent acquisitions: grubs, pupae and +cocoons of all kinds, whose evolution I wished to study. Whenever +these receptacles have an atom of free space, they claim the right to +build there, whereas I formally oppose the claim. I hardly reckoned +on such a success, which obliges me to put some order into the +invasion with which I am threatened. I seal up the locks, I shut my +boxes, I close my various receptacles for old nests, in short I +remove from the building-yard any retreat of which I do not approve. +And now, O my Osmiae, I leave you a free field! + +The work begins with a thorough spring-cleaning of the home. Remnants +of cocoons, dirt consisting of spoilt honey, bits of plaster from +broken partitions, remains of dried Mollusc at the bottom of a shell: +these and much other insanitary refuse must first of all disappear. +Violently the Osmia tugs at the offending object and tears it out; +and then off she goes, in a desperate hurry, to dispose of it far +away from the study. They are all alike, these ardent sweepers: in +their excessive zeal, they fear lest they should block up the place +with a speck of dust which they might drop in front of the new house. +The glass tubes, which I myself have rinsed under the tap, are not +exempt from a scrupulous cleaning. The Osmia dusts them, brushes them +thoroughly with her tarsi and then sweeps them out backwards. What +does she pick up? Not a thing. It makes no difference: as a +conscientious housewife, she gives the place a touch of the broom +nevertheless. + +Now for the provisions and the partition-walls. Here the order of the +work changes according to the diameter of the cylinder. My glass +tubes vary greatly in dimensions. The largest have an inner width of +a dozen millimetres (Nearly half an inch.--Translator's Note.); the +narrowest measure six or seven. (About a quarter of an inch.-- +Translator's Note.) In the latter, if the bottom suit her, the Osmia +sets to work bringing pollen and honey. If the bottom do not suit +her, if the sorghum-pith plug with which I have closed the rear-end +of the tube be too irregular and badly-joined, the Bee coats it with +a little mortar. When this small repair is made, the harvesting +begins. + +In the wider tubes, the work proceeds quite differently. At the +moment when the Osmia disgorges her honey and especially at the +moment when, with her hind-tarsi, she rubs the pollen-dust from her +ventral brush, she needs a narrow aperture, just big enough to allow +of her passage. I imagine that, in a straitened gallery, the rubbing +of her whole body against the sides gives the harvester a support for +her brushing-work. In a spacious cylinder, this support fails her; +and the Osmia starts with creating one for herself, which she does by +narrowing the channel. Whether it be to facilitate the storing of the +victuals or for any other reason, the fact remains that the Osmia +housed in a wide tube begins with the partitioning. + +Her division is made by a dab of clay placed at right angles to the +axis of the cylinder, at a distance from the bottom determined by the +ordinary length of a cell. This wad is not a complete round; it is +more crescent-shaped, leaving a circular space between it and one +side of the tube. Fresh layers are swiftly added to the dab of clay; +and soon the tube is divided by a partition which has a circular +opening at the side of it, a sort of dog-hole through which the Osmia +will proceed to knead the Bee-bread. When the victualling is finished +and the egg laid upon the heap, the hole is closed and the filled-up +partition becomes the bottom of the next cell. Then the same method +is repeated, that is to say, in front of the just completed ceiling a +second partition is built, again with a side-passage, which is +stouter, owing to its distance from the centre, and better able to +withstand the numerous comings and goings of the housewife than a +central orifice, deprived of the direct support of the wall, could +hope to be. When this partition is ready, the provisioning of the +second cell is effected; and so on until the wide cylinder is +completely stocked. + +The building of this preliminary party-wall, with a narrow, round +dog-hole, for a chamber to which the victuals will not be brought +until later is not restricted to the Three-horned Osmia; it is also +frequently found in the case of the Horned Osmia and of Latreille's +Osmia. Nothing could be prettier than the work of the last-named, who +goes to the plants for her material and fashions a delicate sheet in +which she cuts a graceful arch. The Chinaman partitions his house +with paper screens; Latreille's Osmia divides hers with disks of thin +green cardboard perforated with a serving-hatch which remains until +the room is completely furnished. When we have no glass houses at our +disposal, we can see these little architectural refinements in the +reeds of the hurdles, if we open them at the right season. + +By splitting the bramble-stumps in the course of July, we perceive +also that the Three-pronged Osmia, notwithstanding her narrow +gallery, follows the same practice as Latreille's Osmia, with a +difference. She does not build a party-wall, which the diameter of +the cylinder would not permit; she confines herself to putting up a +frail circular pad of green putty, as though to limit, before any +attempt at harvesting, the space to be occupied by the Bee-bread, +whose depth could not be calculated afterwards if the insect did not +first mark out its confines. Can there really be an act of measuring? +That would be superlatively clever. Let us consult the Three-horned +Osmia in her glass tubes. + +The Osmia is working at her big partition, with her body outside the +cell which she is preparing. From time to time, with a pellet of +mortar in her mandibles, she goes in and touches the previous ceiling +with her forehead, while the tip of her abdomen quivers and feels the +pad in course of construction. One might well say that she is using +the length of her body as a measure, in order to fix the next ceiling +at the proper distance. Then she resumes her work. Perhaps the +measure was not correctly taken; perhaps her memory, a few seconds +old, has already become muddled. The Bee once more ceases laying her +plaster and again goes and touches the front wall with her forehead +and the back wall with the tip of her abdomen. Looking at that body +trembling with eagerness, extended to its full length to touch the +two ends of the room, how can we fail to grasp the architect's grave +problem? The Osmia is measuring; and her measure is her body. Has she +quite done, this time? Oh dear no! Ten times, twenty times, at every +moment, for the least particle of mortar which she lays, she repeats +her mensuration, never being quite certain that her trowel is going +just where it should. + +Meanwhile, amid these frequent interruptions, the work progresses and +the partition gains in width. The worker is bent into a hook, with +her mandibles on the inner surface of the wall and the tip of her +abdomen on the outer surface. The soft masonry stands between the two +points of purchase. The insect thus forms a sort of rolling-press, in +which the mud wall is flattened and shaped. The mandibles tap and +furnish mortar; the end of the abdomen also pats and gives brisk +trowel-touches. This anal extremity is a builder's tool; I see it +facing the mandibles on the other side of the partition, kneading and +smoothing it all over, flattening the little lump of clay. It is a +singular implement, which I should never have expected to see used +for this purpose. It takes an insect to conceive such an original +idea, to do mason's work with its behind! During this curious +performance, the only function of the legs is to keep the worker +steady by spreading out and clinging to the walls of the tunnel. + +The partition with the hole in it is finished. Let us go back to the +measuring of which the Osmia was so lavish. What a magnificent +argument in favour of the reasoning-power of animals! To find +geometry, the surveyor's art, in an Osmia's tiny brain! An insect +that begins by taking the measurements of the room to be constructed, +just as any master-builder might do! Why, it's splendid, it's enough +to cover with confusion those horrible sceptics who persist in +refusing to admit the animal's 'continuous little flashes of atoms of +reason!' + +O common-sense, veil your face! It is with this gibberish about +continuous flashes of atoms of reason that men pretend to build up +science to-day! Very well, my masters; the magnificent argument with +which I am supplying you lacks but one little detail, the merest +trifle: truth! Not that I have not seen and plainly seen all that I +am relating; but measuring has nothing to do with the case. And I can +prove it by facts. + +If, in order to see the Osmia's nest as a whole, we split a reed +lengthwise, taking care not to disturb its contents; or, better +still, if we select for examination the string of cells built in a +glass tube, we are forthwith struck by one detail, namely, the uneven +distances between the partitions, which are placed almost at right +angles to the axis of the cylinder. It is these distances which fix +the size of the chambers, which, with a similar base, have different +heights and consequently unequal holding-capacities. The bottom +partitions, the oldest, are farther apart; those of the front part, +near the orifice, are closer together. Moreover, the provisions are +plentiful in the loftier cells, whereas they are niggardly and +reduced to one-half or even one-third in the cells of lesser height. + +Here are a few examples of these inequalities. A glass tube with a +diameter of 12 millimetres (.468 inch.--Translator's Note.), inside +measurement, contains ten cells. The five lower ones, beginning with +the bottom-most, have as the respective distances between their +partitions, in millimetres: + +11, 12, 16, 13, 11. (.429, .468, .624, .507, .429 inch.--Translator's +Note.) + +The five upper ones measure between their partitions: + +7, 7, 5, 6, 7. (.273, .273, .195, .234, .273 inch.--Translator's +Note.) + +A reed-stump 11 millimetres (.429 inch.--Translator's Note.) across +the inside contains fifteen cells; and the respective distances +between the partitions of those cells, starting from the bottom, are: + +13, 12, 12, 9, 9, 11, 8, 8, 7, 7, 7, 6, 6, 6, 7. (.507, .468, .468, +.351, .351, .429, .312, .312, .273, .273, .273, .234, .234, .234, +.273 inch.--Translator's Note.) + +When the diameter of the tunnel is less, the partitions can be still +further apart, though they retain the general characteristic of being +closer to one another the nearer they are to the orifice. A reed of +five millimetres (.195 inch.--Translator's Note.) in diameter, gives +me the following distances, always starting from the bottom: + +22, 22, 20, 20, 12, 14. (.858, .858, .78, .78, .468, .546 inch.-- +Translator's Note.) + +Another, of 9 millimetres (.351 inch.--Translator's Note.), gives me: + +15, 14, 11, 10, 10, 9, 10. (.585, .546, .429, .39, .39, .351, .39 +inch.--Translator's Note.) + +A glass tube of 8 millimetres (.312 inch.--Translator's Note.) +yields: + +15, 14, 20, 10, 10, 10. (.585, .546, .78, .39, .39, .39 inch.-- +Translator's Note.). + +I could fill pages and pages with such figures, if I cared to print +all my notes. Do they prove that the Osmia is a geometrician, +employing a strict measure based on the length of her body? Certainly +not, because many of those figures exceed the length of the insect; +because sometimes a higher number follows suddenly upon a lower; +because the same string contains a figure of one value and another +figure of but half that value. They prove only one thing: the marked +tendency of the insect to shorten the distance between the party- +walls as the work proceeds. We shall see later that the large cells +are destined for the females and the small ones for the males. + +Is there not at least a measuring adapted to each sex? Again, not so; +for in the first series, where the females are housed, instead of the +interval of 11 millimetres, which occurs at the beginning and the +end, we find, in the middle of the series, an interval of 16 +millimetres, while in the second series, reserved for the males, +instead of the interval of 7 millimetres at the beginning and the +end, we have an interval of 5 millimetres in the middle. It is the +same with the other series, each of which shows a striking +discrepancy in its figures. If the Osmia really studied the +dimensions of her chambers and measured them with the compasses of +her body, how could she, with her delicate mechanism, fail to notice +mistakes of 5 millimetres, almost half her own length? + +Besides, all idea of geometry vanishes if we consider the work in a +tube of moderate width. Here, the Osmia does not fix the front +partition in advance; she does not even lay its foundation. Without +any boundary-pad, with no guiding mark for the capacity of the cell, +she busies herself straightway with the provisioning. When the heap +of Bee-bread is judged sufficient, that is, I imagine, when her tired +body tells her that she has done enough harvesting, she closes up the +chamber. In this case, there is no measuring; and yet the capacity of +the cell and the quantity of the victuals fulfil the regular +requirements of one or the other sex. + +Then what does the Osmia do when she repeatedly stops to touch the +front partition with her forehead and the back partition, the one in +the course of building, with the tip of her abdomen? I have no idea +what she does or what she has in view. I leave the interpretation of +this performance to others, more venturesome than I. Plenty of +theories are based on equally shaky foundations. Blow on them and +they sink into the quagmire of oblivion. + +The laying is finished, or perhaps the cylinder is full. A final +partition closes the last cell. A rampart is now built, at the +orifice of the tube itself, to forbid the ill-disposed all access to +the home. This is a thick plug, a massy work of fortification, +whereon the Osmia spends enough mortar to partition off any number of +cells. A whole day is not too long for making this barricade, +especially in view of the minute finishing-touches, when the Osmia +fills up with putty every chink through which the least atom could +slip. The mason completing a wall smooths his plaster and brings it +to a fine surface while it is still wet; the Osmia does the same, or +almost. With little taps of the mandibles and a continual shaking of +her head, a sign of her zest for the work, she smooths and polishes +the surface of the lid for hours at a time. After such pains, what +foe could visit the dwelling? + +And yet there is one, an Anthrax, A. sinuata (Cf. "The Life of the +Fly": chapters 2 and 4.--Translator's Note.), who will come later on, +in the height of summer, and succeed, invisible bit of thread that +she is, in making her way to the grub through the thickness of the +door and the web of the cocoon. In many cells, mischief of another +kind has already been done. During the progress of the works, an +impudent Midge, one of the Tachina-flies, who feeds her family on the +victuals amassed by the Bee, hovers in front of the galleries. Does +she penetrate to the cells and lay her eggs there in the mother's +absence? I could never catch the sneak in the act. Does she, like +that other Tachina who ravages cells stocked with game (The cells of +the Hunting Wasps.--Translator's Note.), nimbly deposit her eggs on +the Osmia's harvest at the moment when the Bee is going indoors? It +is possible, though I cannot say for certain. The fact remains that +we soon see the Midge's grub-worms swarming around the larva, the +daughter of the house. There are ten, fifteen, twenty or more of them +gnawing with their pointed mouths at the common dish and turning the +food into a heap of fine, orange-coloured vermicelli. The Bee's grub +dies of starvation. It is life, life in all its ferocity even in +these tiny creatures. What an expenditure of ardent labour, of +delicate cares, of wise precautions, to arrive at...what? Her +offspring sucked and drained dry by the hateful Anthrax; her family +sweated and starved by the infernal Tachina. + +The victuals consist mostly of yellow flour. In the centre of the +heap, a little honey is disgorged, which turns the pollen-dust into a +firm, reddish paste. On this paste the egg is laid, not flat, but +upright, with the fore-end free and the hind-end lightly held and +fixed in the plastic mass. When hatched, the young grub, kept in its +place by its rear-end, need only bend its neck a little to find the +honey-soaked paste under its mouth. When it grows stronger, it will +release itself from its support and eat up the surrounding flour. + +All this is touching, in its maternal logic. For the new-born, dainty +bread-and-honey; for the adolescent, dry bread. In cases where the +provisions are all of a kind, these delicate precautions are +superfluous. The victuals of the Anthophorae and the Chalicodomae +consist of flowing honey, the same throughout. The egg is then laid +at full length on the surface, without any particular arrangement, +thus compelling the new-born grub to take its first mouthfuls at +random. This has no drawback, as the food is of the same quality +throughout. But, with the Osmia's provisions--dry powder on the +edges, jam in the centre--the grub would be in danger if its first +meal were not regulated in advance. To begin with pollen not seasoned +with honey would be fatal to its stomach. Having no choice of its +mouthfuls because of its immobility and being obliged to feed on the +spot where it was hatched, the young grub must needs be born on the +central mass, where it has only to bend its head a little way in +order to find what its delicate stomach calls for. The place of the +egg, therefore, fixed upright by its base in the middle of the red +jam, is most judiciously chosen. What a contrast between this +exquisite maternal forethought and the horrible destruction by the +Anthrax and the Midge! + +The egg is rather large for the size of the Osmia. It is cylindrical, +slightly curved, rounded at both ends and transparent. It soon +becomes cloudy, while remaining diaphanous at each extremity. Fine +lines, hardly perceptible to the most penetrating lens, show +themselves in transverse circles. These are the first signs of +segmentation. A contraction appears in the front hyaline part, +marking the head. An extremely thin opaque thread runs down either +side. This is the cord of tracheae communicating between one +breathing-hole and another. At last, the segments show distinctly, +with their lateral pads. The grub is born. + +At first, one would think that there was no hatching in the proper +sense of the word--that is to say, no bursting and casting of a +wrapper. The most minute attention is necessary to show that +appearances are deceptive and that actually a fine membrane is thrown +off from front to back. This infinitesimal shred is the shell of the +egg. + +The grub is born. Fixed by its base, it curves into an arc and bends +its head, until now held erect, down to the red mass. The meal +begins. Soon a yellow cord occupying the front two-thirds of the body +proclaims that the digestive apparatus is swelling out with food. For +a fortnight, consume your provender in peace, my child; then spin +your cocoon: you are now safe from the Tachina! Shall you be safe +from the Anthrax' sucker later on? Alack! + + +CHAPTER 3. THE DISTRIBUTION OF THE SEXES. + +Does the insect know beforehand the sex of the egg which it is about +to lay? When examining the stock of food in the cells just now, we +began to suspect that it does, for each little heap of provisions is +carefully proportioned to the needs at one time of a male and at +another of a female. What we have to do is to turn this suspicion +into a certainty demonstrated by experiment. And first let us find +out how the sexes are arranged. + +It is not possible to ascertain the chronological order of a laying, +except by going to suitably-chosen species. Digging up the burrows of +Cerceris-, Bembex- or Philanthus-wasps will never tell us that this +grub has taken precedence of that in point of time nor enable us to +decide whether one cocoon in a colony belongs to the same family as +another. To compile a register of births is absolutely impossible +here. Fortunately there are a few species in which we do not find +this difficulty: these are the Bees who keep to one gallery and build +their cells in storeys. Among the number are the different +inhabitants of the bramble-stumps, notably the Three-pronged Osmiae, +who form an excellent subject for observation, partly because they +are of imposing-size--bigger than any other bramble-dwellers in my +neighbourhood--partly because they are so plentiful. + +Let us briefly recall the Osmia's habits. Amid the tangle of a hedge, +a bramble-stalk is selected, still standing, but a mere withered +stump. In this the insect digs a more or less deep tunnel, an easy +piece of work owing to the abundance of soft pith. Provisions are +heaped up right at the bottom of the tunnel and an egg is laid on the +surface of the food: that is the first-born of the family. At a +height of some twelve millimetres (About half an inch.--Translator's +Note.), a partition is fixed, formed of bramble saw-dust and of a +green paste obtained by masticating particles of the leaves of some +plant that has not yet been identified. This gives a second storey, +which in its turn receives provisions and an egg, the second in order +of primogeniture. And so it goes on, storey by storey, until the +cylinder is full. Then a thick plug of the same green material of +which the partitions are formed closes the home and keeps out +marauders. + +In this common cradle, the chronological order of births is perfectly +clear. The first-born of the family is at the bottom of the series; +the last-born is at the top, near the closed door. The others follow +from bottom to top in the same order in which they followed in point +of time. The laying is numbered automatically; each cocoon tells us +its respective age by the place which it occupies. + +To know the sexes, we must wait for the month of June. But it would +be unwise to postpone our investigations until that period. Osmia- +nests are not so common that we can hope to pick one up each time +that we go out with that object; besides, if we wait for the +hatching-period before examining the brambles, it may happen that the +order has been disturbed through some insects' having tried to make +their escape as soon as possible after bursting their cocoons; it may +happen that the male Osmiae, who are more forward than the females, +are already gone. I therefore set to work a long time beforehand and +devote my leisure in winter to these investigations. + +The bramble-sticks are split and the cocoons taken out one by one and +methodically transferred to glass tubes, of approximately the same +diameter as the native cylinder. These cocoons are arranged one on +top of the other in exactly the same order that they occupied in the +bramble; they are separated from one another by a cotton plug, an +insuperable obstacle to the future insect. There is thus no fear that +the contents of the cells may become mixed or transposed; and I am +saved the trouble of keeping a laborious watch. Each insect can hatch +at its own time, in my presence or not: I am sure of always finding +it in its place, in its proper order, held fast fore and aft by the +cotton barrier. A cork or sorghum-pith partition would not fulfil the +same purpose: the insect would perforate it and the register of +births would be muddled by changes of position. Any reader wishing to +undertake similar investigations will excuse these practical details, +which may facilitate his work. + +We do not often come upon complete series, comprising the whole +laying, from the first-born to the youngest. As a rule, we find part +of a laying, in which the number of cocoons varies greatly, sometimes +falling as low as two, or even one. The mother has not deemed it +advisable to confide her whole family to a single bramble-stump; in +order to make the exit less toilsome, or else for reasons which +escape me, she has left the first home and elected to make a second +home, perhaps a third or more. + +We also find series with breaks in them. Sometimes, in cells +distributed at random, the egg has not developed and the provisions +have remained untouched, but mildewed; sometimes, the larva has died +before spinning its cocoon, or after spinning it. Lastly, there are +parasites, such as the Unarmed Zonitis (Zonitis mutica, one of the +Oil-beetles.--Translator's Note.) and the Spotted Sapyga (A Digger- +wasp.--Translator's Note.), who interrupt the series by substituting +themselves for the original occupant. All these disturbing factors +make it necessary to examine a large number of nests of the Three- +pronged Osmia, if we would obtain a definite result. + +I have been studying the bramble-dwellers for seven or eight years +and I could not say how many strings of cocoons have passed through +my hands. During a recent winter, in view particularly of the +distribution of the sexes, I collected some forty of this Osmia's +nests, transferred their contents into glass tubes and made a careful +summary of the sexes. I give some of my results. The figures start in +their order from the bottom of the tunnel dug in the bramble and +proceed upwards to the orifice. The figure 1 therefore denotes the +first-born of the series, the oldest in date; the highest figure +denotes the last-born. The letter M, placed under the corresponding +figure, represents the male and the letter F the female sex. + +1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 +F F M F M F M M F F F F M F M + +This is the longest series that I have ever been able to procure. It +is also complete, inasmuch as it comprises the entire laying of the +Osmia. My statement requires explaining, otherwise it would seem +impossible to know whether a mother whose acts one has not watched, +nay more, whom one has never seen, has or has not finished laying her +eggs. The bramble-stump under consideration leaves a free space of +nearly four inches above the continuous string of cocoons. Beyond it, +at the actual orifice, is the terminal stopper, the thick plug which +closes the entrance to the gallery. In this empty portion of the +tunnel there is ample accommodation for numerous cocoons. The fact +that the mother has not made use of it proves that her ovaries were +exhausted; for it is exceedingly unlikely that she has abandoned +first-rate lodgings to go laboriously digging a new gallery elsewhere +and there continue her laying. + +You may say that, if the unoccupied space marks the end of the +laying, nothing tells us that the beginning is actually at the bottom +of the cul-de-sac, at the other end of the tunnel. You may also say +that the laying is done in shifts, separated by intervals of rest. +The space left empty in the channel would mean that one of these +shifts was finished and not that there were no more eggs ripe for +hatching. In answer to these very plausible explanations, I will say +that, the sum of my observations--and they have been extremely +numerous--is that the total number of eggs laid not only by the +Osmiae but by a host of other Bees fluctuates round about fifteen. + +Besides, when we consider that the active life of these insects lasts +hardly a month; when we remember that this period of activity is +disturbed by dark, rainy or very windy days, during which all work is +suspended; when lastly we ascertain, as I have done ad nauseam in the +case of the Three-horned Osmia, the time required for building and +victualling a cell, it becomes obvious that the total laying must be +kept within narrow bounds and that the mother has no time to lose if +she wishes to get fifteen cells satisfactorily built in three or four +weeks interrupted by compulsory rests. I shall give some facts later +which will dispel your doubts, if any remain. + +I assume, therefore, that a number of eggs bordering on fifteen +represents the entire family of an Osmia, as it does of many other +Bees. + +Let us consult some other complete series. Here are two: + +1 2 3 4 5 6 7 8 9 10 11 12 13 +F F M F M F M F F F F M F +F M F F F M F F M F M + +In both cases, the laying is taken as complete, for the same reasons +as above. + +We will end with some series that appear to me incomplete, in view of +the small number of cells and the absence of any free space above the +pile of cocoons: + +1 2 3 4 5 6 7 8 +M M F M M M M M +M M F M F M M M +F M F F M M +M M M F M +F F F F +M M M +F M + +These examples are more than sufficient. It is quite evident that the +distribution of the sexes is not governed by any rule. All that I can +say on consulting the whole of my notes, which contain a good many +instances of complete layings--most of them, unfortunately, spoilt +through gaps caused by parasites, the death of the larva, the failure +of the egg to hatch and other accidents--all that I can say in +general is that the complete series begins with females and nearly +always ends with males. The incomplete series can teach us nothing in +this respect, for they are only fragments starting we know not +whence; and it is impossible to tell whether they should be ascribed +to the beginning, to the end, or to an intermediate period of the +laying. To sum up: in the laying of the Three-pronged Osmia, no order +governs the succession of the sexes; only, the series has a marked +tendency to begin with females and to finish with males. + +The brambles, in my district, harbour two other Osmiae, both of much +smaller size: O. detrita, PEREZ, and O. parvula, DUF. The first is +very common, the second very rare; and until now I have found only +one of her nests, placed above a nest of O. detrita, in the same +bramble. Here, instead of the lack of order in the distribution of +the sexes which we find with O. tridentata, we have an order +remarkable for consistency and simplicity. I have before me the list +of the series of O. detrita collected last winter. Here are some of +them: + +1. A series of twelve: seven females, beginning with the bottom of +the tunnel, and then five males. + +2. A series of nine: three females first, then six males. + +3. A series of eight: five females followed by three males. + +4. A series of eight: seven females followed by one male. + +5. A series of eight: one female followed by seven males. + +6. A series of seven: six females followed by one male. + +The first series might very well be complete. The second and fifth +appear to be the end of layings, of which the beginning has taken +place elsewhere, in another bramble-stump. The males predominate and +finish off the series. Nos. 3, 4 and 6, on the other hand, look like +the beginnings of layings: the females predominate and are at the +head of the series. Even if these interpretations should be open to +doubt, one result at least is certain: with O. detrita, the laying is +divided into two groups, with no intermingling of the sexes; the +first group laid yields nothing but females, the second, or more +recent, yields nothing but males. + +What was only a sort of attempt with the Three-pronged Osmia--who, it +is true, begins with females and ends with males, but muddles up the +order and mixes the two sexes anyhow between the extreme points-- +becomes a regular law with her kinswoman. The mother occupies herself +at the start with the stronger sex, the more necessary, the better- +gifted, the female sex, to which she devotes the first flush of her +laying and the fullness of her vigour; later, when she is perhaps +already at the end of her strength, she bestows what remains of her +maternal solicitude upon the weaker sex, the less-gifted, almost +negligible male sex. + +O. parvula, of whom I unfortunately possess but one series, repeats +what the previous witness has just shown us. This series, one of nine +cocoons, comprises five females followed by four males, without any +mixing of the sexes. + +Next to these disgorgers of honey and gleaners of pollen-dust, it +would be well to consult other Hymenoptera, Wasps who devote +themselves to the chase and pile their cells one after the other, in +a row, showing the relative age of the cocoons. The brambles house +several of these: Solenius vagus, who stores up Flies; Psen atratus, +who provides her grubs with a heap of Plant-lice; Trypoxylon figulus, +who feeds them with Spiders. + +Solenius vagus digs her gallery in a bramble-stick that is lopped +short, but still fresh and green. The house of this Fly-huntress, +therefore, suffers from damp, as the sap enters, especially on the +lower floors. This seems to me rather insanitary. To avoid the +humidity, or for other reasons which escape me, the Solenius does not +dig very far into her bramble-stump and consequently can stack but a +small number of cells in it. A series of five cocoons gives me first +four females and then one male; another series, also of five, +contains first three females, with two males following. These are the +most complete that I have for the moment. + +I reckoned on the Black Psen, or Psen atratus, whose series are +pretty long; it is a pity that they are nearly always greatly +interfered with by a parasite called Ephialtes mediator. (Cf. "The +Life of the Fly": chapter 2.--Translator's Note.) I obtained only +three series free from gaps: one of eight cocoons, comprising only +females; one of six, likewise consisting wholly of females; lastly, +one of eight, formed exclusively of males. These instances seem to +show that the Psen arranges her laying in a succession of females and +a succession of males; but they tell us nothing of the relative order +of the two series. + +>From the Spider-huntress, Trypoxylon figulus, I learnt nothing +decisive. She appeared to me to rove about from one bramble to the +next, utilizing galleries which she has not dug herself. Not +troubling to be economical with a lodging which it has cost her +nothing to acquire, she carelessly builds a few partitions at very +unequal heights, stuffs three or four compartments with Spiders and +passes on to another bramble-stump, with no reason, so far as I know, +for abandoning the first. Her cells, therefore, occur in series that +are too short to give us any useful information. + +This is all that the bramble-dwellers have to tell us; I have +enumerated the list of the principal ones in my district. We will now +look into some other Bees who arrange their cocoons in single files: +the Megachiles (Cf. Chapter 8 of the present volume.--Translator's +Note.), who cut disks out of leaves and fashion the disks into +thimble-shaped receptacles; the Anthidia (Cf. Chapters 9 and 10 of +the present volume.--Translator's Note.), who weave their honey- +wallets out of cotton-wool and arrange their cells one after the +other in some cylindrical gallery. In most cases, the home is the +produce of neither the one nor the other. A tunnel in the upright, +earthy banks, the old work of some Anthophora, is the usual dwelling. +There is no great depth to these retreats; and all my searches, +zealously prosecuted during a number of winters, procured me only +series containing a small number of cocoons, four or five at most, +often one alone. And, what is quite as serious, nearly all these +series are spoilt by parasites and allow me to draw no well-founded +deductions. + +I remembered finding, at rare intervals, nests of both the Anthidium +and the Megachile in the hollows of cut reeds. I thereupon installed +some hives of a new kind on the sunniest walls of my enclosure. They +consisted of stumps of the great reed of the south, open at one end, +closed at the other by the natural knot and gathered into a sort of +enormous pan-pipe, such as Polyphemus might have employed. The +invitation was accepted: Osmiae, Anthidia and Megachiles came in +fairly large numbers, especially the first, to benefit by the queer +installation. + +In this way I obtained some magnificent series of Anthidia and +Megachiles, running up to a dozen. There was a melancholy side to +this success. All my series, with not one exception, were ravaged by +parasites. Those of the Megachile (M. sericans, FONSCOL), who +fashions her goblets with robinia-, holm-, and terebinth-leaves, were +inhabited by Coelioxys octodentata (A Parasitic Bee.--Translator's +Note.); those of the Anthidium (A. florentinum, LATR.) were occupied +by a Leucopsis. Both kinds were swarming with a colony of pigmy +parasites whose name I have not yet been able to discover. In short, +my pan-pipe hives, though very useful to me from other points of +view, taught me nothing about the order of the sexes among the Leaf- +cutters and the cotton-weavers. + +I was more fortunate with three Osmiae (O. tricornis, LATR., O. +cornuta, LATR., and O. Latreillii, SPIN.), all of whom gave me +splendid results, with reed-stumps arranged either against the walls +of my garden, as I have just said, or near their customary abode, the +huge nests of the Mason-bee of the Sheds. One of them, the Three- +horned Osmia, did better still: as I have described, she built her +nests in my study, as plentifully as I could wish, using reeds, glass +tubes and other retreats of my selecting for her galleries. + +We will consult this last, who has furnished me with documents beyond +my fondest hopes, and begin by asking her of how many eggs her +average laying consists. Of the whole heap of colonized tubes in my +study, or else out of doors, in the hurdle-reeds and the pan-pipe +appliances, the best-filled contains fifteen cells, with a free space +above the series, a space showing that the laying is ended, for, if +the mother had any more eggs available, she would have lodged them in +the room which she leaves unoccupied. This string of fifteen appears +to be rare; it was the only one that I found. My attempts at indoor +rearing, pursued during two years with glass tubes or reeds, taught +me that the Three-horned Osmia is not much addicted to long series. +As though to decrease the difficulties of the coming deliverance, she +prefers short galleries, in which only a part of the laying is +stacked. We must then follow the same mother in her migration from +one dwelling to the next if we would obtain a complete census of her +family. A spot of colour, dropped on the Bee's thorax with a paint- +brush while she is absorbed in closing up the mouth of the tunnel, +enables us to recognize the Osmia in her various homes. + +In this way, the swarm that resided in my study furnished me, in the +first year, with an average of twelve cells. Next year, the summer +appeared to be more favourable and the average became rather higher, +reaching fifteen. The most numerous laying performed under my eyes, +not in a tube, but in a succession of Snail-shells, reached the +figure of twenty-six. On the other hand, layings of between eight and +ten are not uncommon. Lastly, taking all my records together, the +result is that the family of the Osmia fluctuates round about fifteen +in number. + +I have already spoken of the great differences in size apparent in +the cells of one and the same series. The partitions, at first widely +spaced, draw gradually nearer to one another as they come closer to +the aperture, which implies roomy cells at the back and narrow cells +in front. The contents of these compartments are no less uneven +between one portion and another of the string. Without any exception +known to me, the large cells, those with which the series starts, +have more abundant provisions than the straitened cells with which +the series ends. The heap of honey and pollen in the first is twice +or even thrice as large as that in the second. In the last cells, the +most recent in date, the victuals are but a pinch of pollen, so +niggardly in amount that we wonder what will become of the larva with +that meagre ration. + +One would think that the Osmia, when nearing the end of the laying, +attaches no importance to her last-born, to whom she doles out space +and food so sparingly. The first-born receive the benefit of her +early enthusiasm: theirs is the well-spread table, theirs the +spacious apartments. The work has begun to pall by the time that the +last eggs are laid; and the last-comers have to put up with a scurvy +portion of food and a tiny corner. + +The difference shows itself in another way after the cocoons are +spun. The large cells, those at the back, receive the bulky cocoons; +the small ones, those in front, have cocoons only a half or a third +as big. Before opening them and ascertaining the sex of the Osmia +inside, let us wait for the transformation into the perfect insect, +which will take place towards the end of summer. If impatience gets +the better of us, we can open them at the end of July or in August. +The insect is then in the nymphal stage; and it is easy, under this +form, to distinguish the two sexes by the length of the antennae, +which are larger in the males, and by the glassy protuberances on the +forehead, the sign of the future armour of the females. Well, the +small cocoons, those in the narrow front cells, with their scanty +store of provisions, all belong to males; the big cocoons, those in +the spacious and well-stocked cells at the back, all belong to +females. + +The conclusion is definite: the laying of the Three-horned Osmia +consists of two distinct groups, first a group of females and then a +group of males. + +With my pan-pipe apparatus displayed on the walls of my enclosure and +with old hurdle-reeds left lying flat out of doors, I obtained the +Horned Osmia in fair quantities. I persuaded Latreille's Osmia to +build her nest in reeds, which she did with a zeal which I was far +from expecting. All that I had to do was to lay some reed-stumps +horizontally within her reach, in the immediate neighbourhood of her +usual haunts, namely, the nests of the Mason-bee of the Sheds. +Lastly, I succeeded without difficulty in making her build her nests +in the privacy of my study, with glass tubes for a house. The result +surpassed my hopes. + +With both these Osmiae, the division of the gallery is the same as +with the Three-horned Osmia. At the back are large cells with +plentiful provisions and widely-spaced partitions; in front, small +cells, with scanty provisions and partitions close together. Also, +the larger cells supplied me with big cocoons and females; the +smaller cells gave me little cocoons and males. The conclusion +therefore is exactly the same in the case of all three Osmiae. + +Before dismissing the Osmiae, let us devote a moment to their +cocoons, a comparison of which, in the matter of bulk, will furnish +us with fairly accurate evidence as to the relative size of the two +sexes, for the thing contained, the perfect insect, is evidently +proportionate to the silken wrapper in which it is enclosed. These +cocoons are oval-shaped and may be regarded as ellipsoids formed by a +revolution around the major axis. The volume of one of these solids +is expressed in the following formula: + +4 / 3 x pi x a x (b squared), + +in which 2a is the major axis and 2b the minor axis. + +Now, the average dimensions of the cocoons of the Three-horned Osmia +are as follows: + +2a = 13 mm. (.507 inch.--Translator's Note.), 2b = 7 mm. (.273 inch.- +-Translator's Note.) in the females; + +2a = 9 mm. (.351 inch.--Translator's Note.), 2b = 5 mm. (.195 inch.-- +Translator's Note.) in the males. + +The ratio therefore between 13 x 7 x 7 = 637 and 9 x 5 x 5 = 225 will +be more or less the ratio between the sizes of the two sexes. This +ratio is somewhere between 2 to 1 and 3 to 1. The females therefore +are two or three times larger than the males, a proportion already +suggested by a comparison of the mass of provisions, estimated simply +by the eye. + +The Horned Osmia gives us the following average dimensions: + +2a = 15 mm. (.585 inch.--Translator's Note.), 2b = 9 mm. (.351 inch.- +-Translator's Note.) in the females; + +2a = 12 mm. (.468 inch.--Translator's Note.), 2b = 7 mm. (.273 inch.- +-Translator's Note.) in the males. + +Once again, the ratio between 15 x 9 x 9 = 1215 and 12 x 7 x 7 = 588 +lies between 2 to 1 and 3 to 1. + +Besides the Bees who arrange their laying in a row, I have consulted +others whose cells are grouped in a way that makes it possible to +ascertain the relative order of the two sexes, though not quite so +precisely. One of these is the Mason-bee of the Walls. I need not +describe again her dome-shaped nest, built on a pebble, which is now +so well-known to us. (Cf. "The Mason-bees": chapter 1.--Translator's +Note.) + +Each mother chooses her stone and works on it in solitude. She is an +ungracious landowner and guards her site jealously, driving away any +Mason who even looks as though she might alight on it. The +inhabitants of the same nest are therefore always brothers and +sisters; they are the family of one mother. + +Moreover, if the stone presents a large enough surface--a condition +easily fulfilled--the Mason-bee has no reason to leave the support on +which she began her laying and go in search of another whereon to +deposit the rest of her eggs. She is too thrifty of her time and of +her mortar to involve herself in such expenditure except for grave +reasons. Consequently, each nest, at least when it is new, when the +Bee herself has laid the first foundations, contains the entire +laying. It is a different thing when an old nest is restored and made +into a place for depositing the eggs. I shall come back later to such +houses. + +A newly-built nest then, with rare exceptions, contains the entire +laying of one female. Count the cells and we shall have the total +list of the family. Their maximum number fluctuates round about +fifteen. The most luxuriant series will occasionally reach as many as +eighteen, though these are very scarce. + +When the surface of the stone is regular all around the site of the +first cell, when the mason can add to her building with the same +facility in every direction, it is obvious that the groups of cells, +when finished, will have the oldest in the central portion and the +more recent in the surrounding portion. Because of this juxtaposition +of the cells, which serve partly as a wall to those which come next, +it is possible to form some estimate of the chronological order of +the cells in the Chalicodoma's nest and thus to discover the sequence +of the two sexes. + +In winter, by which time the Bee has long been in the perfect state, +I collect Chalicodoma-nests, removing them bodily from their support +with a few smart sideward taps of the hammer on the pebbles. At the +base of the mortar dome the cells are wide agape and display their +contents. I take the cocoon from its box, open it and take note of +the sex of the insect enclosed. + +I should probably be accused of exaggeration if I mentioned the total +number of the nests which I have gathered and the cells which I have +inspected by this method during the last six or seven years. I will +content myself with saying that the harvest of a single morning +sometimes consisted of as many as sixty nests of the Mason-bee. I had +to have help in carrying home my spoils, even though the nests were +removed from their stones on the spot. + +>From the enormous number of nests which I have examined, I am able to +state that, when the cluster is regular, the female cells occupy the +centre and the male cells the edges. Where the irregularity of the +pebble has prevented an even distribution around the initial point, +the same rule has been observed. A male cell is never surrounded on +every side by female cells: either it occupies the edges of the nest, +or else it adjoins, at least on some sides, other male cells, of +which the last form part of the exterior of the cluster. As the +surrounding cells are obviously of a later date than the inner cells, +it follows that the Mason-bee acts like the Osmiae: she begins her +laying with females and ends it with males, each of the sexes forming +a series of its own, independent of the other. + +Some further circumstances add their testimony to that of the +surrounded and surrounding cells. When the pebble projects sharply +and forms a sort of dihedral angle, one of whose faces is more or +less vertical and the other horizontal, this angle is a favourite +site with the Mason, who thus finds greater stability for her edifice +in the support given her by the double plane. These sites appear to +me to be in great request with the Chalicodoma, considering the +number of nests which I find thus doubly supported. In nests of this +kind, all the cells, as usual, have their foundations fixed to the +horizontal surface; but the first row, the row of cells first built, +stands with its back against the vertical surface. + +Well, these older cells, which occupy the actual edge of the dihedral +angle, are always female, with the exception of those at either end +of the row, which, as they belong to the outside, may be male cells. +In front of this first row come others. The female cells occupy the +middle portion and the male the ends. Finally, the last row, closing +in the remainder, contains only male cells. The progress of the work +is very visible here: the Mason has begun by attending to the central +group of female cells, the first row of which occupies the dihedral +angle, and has finished her task by distributing the male cells round +the outside. + +If the perpendicular face of the dihedral angle be high enough, it +sometimes happens that a second row of cells is placed above the +first row backing on to that plane; a third row occurs less often. +The nest is then one of several storeys. The lower storeys, the +older, contain only females; the upper, the more recent storey, +contains none but males. It goes without saying that the surface +layer, even of the lower storeys, can contain males without +invalidating the rule, for this layer may always be looked upon as +the Chalicodoma's last work. + +Everything therefore contributes to show that, in the Mason-bee, the +females take the lead in the order of primogeniture. Theirs is the +central and best-protected part of the clay fortress; the outer part, +that most exposed to the inclemencies of the weather and to +accidents, is for the males. + +The males' cells do not differ from the females' only by being placed +at the outside of the cluster; they differ also in their capacity, +which is much smaller. To estimate the respective capacities of the +two sorts of cells, I go to work as follows: I fill the empty cell +with very fine sand and pour this sand back into a glass tube +measuring 5 millimetres (.195 inch.--Translator's Note.) in diameter. +>From the height of the column of sand we can estimate the comparative +capacity of the two kinds of cells. I will take one at random among +my numerous examples of cells thus gauged. + +It comprises thirteen cells and occupies a dihedral angle. The female +cells give me the following figures, in millimetres, as the height of +the columns of sand: + +40, 44, 43, 48, 48, 46, 47 +(1.56, 1.71, 1.67, 1.87, 1.87, 1.79, 1.83 inches.--Translator's +Note.), + +averaging 45. (1.75 inches.--Translator's Note.) + +The male cells give me: + +32, 35, 28, 30, 30, 31 +(1.24, 1.36, 1.09, 1.17, 1.17, 1.21 inches.--Translator's Note.), + +averaging 31. (1.21 inches.--Translator's Note.) + +The ratio of the capacity of the cells for the two sexes is therefore +roughly a ratio of 4 to 3. The actual contents of the cell being +proportionate to its capacity, the above ratio must also be more or +less the ratio of provisions and sizes between females and males. +These figures will assist us presently to tell whether an old cell, +occupied for a second or third time, belonged originally to a female +or a male. + +The Chalicodoma of the Sheds cannot give us any information on this +matter. She builds under the same eaves, in excessively populous +colonies; and it is impossible to follow the labours of any single +Mason, whose cells, distributed here and there, are soon covered up +with the work of her neighbours. All is muddle and confusion in the +individual output of the swarming throng. + +I have not watched the work of the Chalicodoma of the Shrubs with +close enough attention to be able to state definitely that this Bee +is a solitary builder. Her nest is a ball of clay hanging from a +bough. Sometimes, this nest is the size of a large walnut and then +appears to be the work of one alone; sometimes, it is the size of a +man's fist, in which case I have no doubt that it is the work of +several. Those bulky nests, comprising more than fifty cells, can +tell us nothing exact, as a number of workers must certainly have +collaborated to produce them. + +The walnut-sized nests are more trustworthy, for everything seems to +indicate that they were built by a single Bee. Here females are found +in the centre of the group and males at the circumference, in +somewhat smaller cells, thus repeating what the Mason-bee of the +Pebbles has told us. + +One clear and simple rule stands out from this collection of facts. +Apart from the strange exception of the Three-pronged Osmia, who +mixes the sexes without any order, the Bees whom I studied and +probably a crowd of others produce first a continuous series of +females and then a continuous series of males, the latter with less +provisions and smaller cells. This distribution of the sexes agrees +with what we have long known of the Hive-bee, who begins her laying +with a long sequence of workers, or sterile females, and ends it with +a long sequence of males. The analogy continues down to the capacity +of the cells and the quantities of provisions. The real females, the +Queen-bees, have wax cells incomparably more spacious than the cells +of the males and receive a much larger amount of food. Everything +therefore demonstrates that we are here in the presence of a general +rule. + +But does this rule express the whole truth? Is there nothing beyond a +laying in two series? Are the Osmiae, the Chalicodomae and the rest +of them fatally bound by this distribution of the sexes into two +distinct groups, the male group following upon the female group, +without any mixing of the two? Is the mother absolutely powerless to +make a change in this arrangement, should circumstances require it? + +The Three-pronged Osmia already shows us that the problem is far from +being solved. In the same bramble-stump, the two sexes occur very +irregularly, as though at random. Why this mixture in the series of +cocoons of a Bee closely related to the Horned Osmia and the Three- +horned Osmia, who stack theirs methodically by separate sexes in the +hollow of a reed? What the Bee of the brambles does cannot her +kinswomen of the reeds do too? Nothing, so far as I know, can explain +this difference in a physiological act of primary importance. The +three Bees belong to the same genus; they resemble one another in +general outline, internal structure and habits; and, with this close +similarity, we suddenly find a strange dissimilarity. + +There is just one thing that might possibly arouse a suspicion of the +cause of this irregularity in the Three-pronged Osmia's laying. If I +open a bramble-stump in the winter to examine the Osmia's nest, I +find it impossible, in the vast majority of cases, to distinguish +positively between a female and a male cocoon: the difference in size +is so small. The cells, moreover, have the same capacity: the +diameter of the cylinder is the same throughout and the partitions +are almost always the same distance apart. If I open it in July, the +victualling-period, it is impossible for me to distinguish between +the provisions destined for the males and those destined for the +females. The measurement of the column of honey gives practically the +same depth in all the cells. We find an equal quantity of space and +food for both sexes. + +This result makes us foresee what a direct examination of the two +sexes in the adult form tells us. The male does not differ materially +from the female in respect of size. If he is a trifle smaller, it is +scarcely noticeable, whereas, in the Horned Osmia and the Three- +horned Osmia, the male is only half or a third the size of the +female, as we have seen from the respective bulk of their cocoons. In +the Mason-bee of the Walls there is also a difference in size, though +less pronounced. + +The Three-pronged Osmia has not therefore to trouble about adjusting +the dimensions of the dwelling and the quantity of the food to the +sex of the egg which she is about to lay; the measure is the same +from one end of the series to the other. It does not matter if the +sexes alternate without order: one and all will find what they need, +whatever their position in the row. The two other Osmiae, with their +great disparity in size between the two sexes, have to be careful +about the twofold consideration of board and lodging. And that, I +think, is why they begin with spacious cells and generous rations for +the homes of the females and end with narrow, scantily-provisioned +cells, the homes of the males. With this sequence, sharply defined +for the two sexes, there is less fear of mistakes which might give to +one what belongs to another. If this is not the explanation of the +facts, I see no other. + +The more I thought about this curious question, the more probable it +appeared to me that the irregular series of the Three-pronged Osmia +and the regular series of the other Osmiae, of the Chalicodomae and +of the Bees in general were all traceable to a common law. It seemed +to me that the arrangement in a succession first of females and then +of males did not account for everything. There must be something +more. And I was right: that arrangement in series is only a tiny +fraction of the reality, which is remarkable in a very different way. +This is what I am going to prove by experiment. + + +CHAPTER 4. THE MOTHER DECIDES THE SEX OF THE EGG. + +I will begin with the Mason-bee of the Pebbles. (This is the same +insect as the Mason-bee of the Walls. Cf. "The Mason-bees": passim.-- +Translator's Note.) The old nests are often used, when they are in +good enough repair. Early in the season the mothers quarrel fiercely +over them; and, when one of the Bees has taken possession of the +coveted dome, she drives any stranger away from it. The old house is +far from being a ruin, only it is perforated with as many holes as it +once had occupants. The work of restoration is no great matter. The +heap of earth due to the destruction of the lid by the outgoing +tenant is taken out of the cell and flung away at a distance, atom by +atom. The remnants of the cocoon are also thrown away, but not +always, for the delicate silken wrapper sometimes adheres closely to +the masonry. + +The victualling of the renovated cell is now begun. Next comes the +laying; and lastly the orifice is sealed with a mortar plug. A second +cell is utilized in the same way, followed by a third and so on, one +after the other, as long as any remain unoccupied and the mother's +ovaries are not exhausted. Finally, the dome receives, mainly over +the apertures already plugged, a coat of plaster which makes the nest +look like new. If she has not finished her laying, the mother goes in +search of other old nests to complete it. Perhaps she does not decide +to found a new establishment except when she can find no second-hand +dwellings, which mean a great economy of time and labour. In short, +among the countless number of nests which I have collected, I find +many more ancient than recent ones. + +How shall we distinguish one from the other? The outward aspect tells +you nothing, owing to the great care taken by the Mason to restore +the surface of the old dwelling equal to new. To resist the rigours +of the winter, this surface must be impregnable. The mother knows +that and therefore repairs the dome. Inside, it is another matter: +the old nest stands revealed at once. There are cells whose +provisions, at least a year old, are intact, but dried up or musty, +because the egg has never developed. There are others containing a +dead larva, reduced by time to a blackened, curled-up cylinder. There +are some whence the perfect insect was never able to issue: the +Chalicodoma wore herself out in trying to pierce the ceiling of her +chamber; her strength failed her and she perished in the attempt. +Others again and very many are occupied by ravagers, Leucopses (Cf. +"The Mason-bees": chapter 11.--Translator's Note.) and Anthrax-flies, +who will come out a good deal later, in July. Altogether, the house +is far from having every room vacant; there are nearly always a +considerable number occupied either by parasites that were still in +the egg-stage at the time when the Mason-bee was at work or by +damaged provisions, dried grubs or Chalicodomae in the perfect state +who have died without being able to effect their deliverance. + +Should all the rooms be available, a rare occurrence, there still +remains a method of distinguishing between an ancient nest and a +recent one. The cocoon, as I have said, adheres pretty closely to the +walls; and the mother does not always take away this remnant, either +because she is unable to do so, or because she considers the removal +unnecessary. Thus the base of the new cocoon is set in the bottom of +the old cocoon. This double wrapper points very clearly to two +generations, two separate years. I have even found as many as three +cocoons fitting one into another at their bases. Consequently, the +nests of the Mason-bee of the Pebbles are able to do duty for three +years, if not more. Eventually they become utter ruins, abandoned to +the Spiders and to various smaller Bees or Wasps, who take up their +quarters in the crumbling rooms. + +As we see, an old nest is hardly ever capable of containing the +Mason-bee's entire laying, which calls for some fifteen apartments. +The number of rooms at her disposal is most unequal, but always very +small. It is saying much when there are enough to receive about half +the laying. Four or five cells, sometimes two or even one: that is +what the Mason usually finds in a nest that is not her own work. This +large reduction is explained when we remember the numerous parasites +that live upon the unfortunate Bee. + +Now, how are the sexes distributed in those layings which are +necessarily broken up between one old nest and another? They are +distributed in such a way as utterly to upset the idea of an +invariable succession first of females and then of males, the idea +which occurs to us on examining the new nests. If this rule were a +constant one, we should be bound to find in the old domes at one time +only females, at another only males, according as the laying was at +its first or at its second stage. The simultaneous presence of the +two sexes would then correspond with the transition period between +one stage and the next and should be very unusual. On the contrary, +it is very common; and, however few cells there may be, we always +find both females and males in the old nests, on the sole condition +that the compartments have the regulation holding-capacity, a large +capacity for the females, a lesser for the males, as we have seen. + +The old male cells can be recognized by their position on the outer +edges and by their capacity, measuring on an average the same as a +column of sand 31 millimetres high in a glass tube 5 millimetres +wide. (1.21 x .195 inches.--Translator's Note.) These cells contain +males of the second or third generation and none but males. In the +old female cells, those in the middle, whose capacity is measured by +a similar column of sand 45 millimetres high (1.75 inches.-- +Translator's Note.), are females and none but females. + +This presence of both sexes at a time, even when there are but two +cells free, one spacious and the other small, proves in the plainest +fashion that the regular distribution observed in the complete nests +of recent production is here replaced by an irregular distribution, +harmonizing with the number and holding-capacity of the chambers to +be stocked. The Mason-bee has before her, let me suppose, only five +vacant cells: two larger and three smaller. The total space at her +disposal would do for about a third of the laying. Well, in the two +large cells, she puts females; in the three small cells, she puts +males. + +As we find the same sort of thing in all the old nests, we must needs +admit that the mother knows the sex of the egg which she is going to +lay, because that egg is placed in a cell of the proper capacity. We +can go further and admit that the mother alters the order of +succession of the sexes at her pleasure, because her layings, between +one old nest and another, are broken up into small groups of males +and females according to the exigencies of space in the actual nest +which she happens to be occupying. + +Just now, in the new nest, we saw the Mason-bee arranging her total +laying into series first of females and next of males; and here she +is, mistress of an old nest of which she has not the power to alter +the arrangement, breaking up her laying into sections comprising both +sexes just as required by the conditions imposed upon her. She +therefore decides the sex of the egg at will, for, without this +prerogative, she could not, in the chambers of the nest which she +owes to chance, deposit unerringly the sex for which those chambers +were originally built; and this happens however small the number of +chambers to be filled. + +When the nest is new, I think I see a reason why the Mason-bee should +seriate her laying into females and then males. Her nest is a half- +sphere. That of the Mason-bee of the Shrubs is very nearly a sphere. +Of all shapes, the spherical shape is the strongest. Now these two +nests require an exceptional power of resistance. Without protection +of any kind, they have to brave the weather, one on its pebble, the +other on its bough. Their spherical configuration is therefore very +practical. + +The nest of the Mason-bee of the Walls consists of a cluster of +upright cells backing against one another. For the whole to take a +spherical form, the height of the chambers must diminish from the +centre of the dome to the circumference. Their elevation is the sine +of the meridian arc starting from the plane of the pebble. Therefore, +if they are to have any solidity, there must be large cells in the +middle and small cells at the edges. And, as the work begins with the +central chambers and ends with those on the circumference, the laying +of the females, destined for the large cells, must precede that of +the males, destined for the small cells. So the females come first +and the males at the finish. + +This is all very well when the mother herself founds the dwelling, +when she lays the first rows of bricks. But, when she is in the +presence of an old nest, of which she is quite unable to alter the +general arrangement, how is she to make use of the few vacant rooms, +the large and the small alike, if the sex of the egg be already +irrevocably fixed? She can only do so by abandoning the arrangement +in two consecutive rows and accommodating her laying to the varied +exigencies of the home. Either she finds it impossible to make an +economical use of the old nest, a theory refuted by the evidence, or +else she determines at will the sex of the egg which she is about to +lay. + +The Osmiae themselves will furnish the most conclusive evidence on +the latter point. We have seen that these Bees are not generally +miners, who themselves dig out the foundation of their cells. They +make use of the old structures of others, or else of natural +retreats, such as hollow stems, the spirals of empty shells and +various hiding-places in walls, clay or wood. Their work is confined +to repairs to the house, such as partitions and covers. There are +plenty of these retreats; and the insect would always find first- +class ones if it thought of going any distance to look for them. But +the Osmia is a stay-at-home: she returns to her birth-place and +clings to it with a patience extremely difficult to exhaust. It is +here, in this little familiar corner, that she prefers to settle her +progeny. But then the apartments are few in number and of all shapes +and sizes. There are long and short ones, spacious ones and narrow. +Short of expatriating herself, a Spartan course, she has to use them +all, from first to last, for she has no choice. Guided by these +considerations, I embarked on the experiments which I will now +describe. + +I have said how my study, on two separate occasions, became a +populous hive, in which the Three-horned Osmia built her nests in the +various appliances which I had prepared for her. Among these +appliances, tubes, either of glass or reed, predominated. There were +tubes of all lengths and widths. In the long tubes, entire or almost +entire layings, with a series of females followed by a series of +males, were deposited. As I have already referred to this result, I +will not discuss it again. The short tubes were sufficiently varied +in length to lodge one or other portion of the total laying. Basing +my calculations on the respective lengths of the cocoons of the two +sexes, on the thickness of the partitions and the final lid, I +shortened some of these to the exact dimensions required for two +cocoons only, of different sexes. + +Well, these short tubes, whether of glass or reed, were seized upon +as eagerly as the long tubes. Moreover, they yielded this splendid +result: their contents, only a part of the total laying, always began +with female and ended with male cocoons. This order was invariable; +what varied was the number of cells in the long tubes and the +proportion between the two sorts of cocoons, sometimes males +predominating and sometimes females. + +The experiment is of paramount importance; and it will perhaps make +the result clearer if I quote one instance from among a multitude of +similar cases. I give the preference to this particular instance +because of the rather exceptional fertility of the laying. An Osmia +marked on the thorax is watched, day by day, from the commencement to +the end of her work. From the 1st to the 10th of May, she occupies a +glass tube in which she lodges seven females followed by a male, +which ends the series. From the 10th to the 17th of May, she +colonizes a second tube, in which she lodges first three females and +then three males. From the 17th to the 25th of May, a third tube, +with three females and then two males. On the 26th of May, a fourth +tube, which she abandons, probably because of its excessive width, +after laying one female in it. Lastly, from the 26th to the 30th of +May, a fifth tube, which she colonizes with two females and three +males. Total: twenty-five Osmiae, including seventeen females and +eight males. And it will not be superfluous to observe that these +unfinished series do not in any way correspond with periods separated +by intervals of rest. The laying is continuous, in so far as the +variable condition of the atmosphere allows. As soon as one tube is +full and closed, another is occupied by the Osmia without delay. + +The tubes reduced to the exact length of two cells fulfilled my +expectation in the great majority of cases: the lower cell was +occupied by a female and the upper by a male. There were a few +exceptions. More discerning than I in her estimate of what was +strictly necessary, better-versed in the economy of space, the Osmia +had found a way of lodging two females where I had only seen room for +one female and a male. + +This experiment speaks volumes. When confronted with tubes too small +to receive all her family, she is in the same plight as the Mason-bee +in the presence of an old nest. She thereupon acts exactly as the +Chalicodoma does. She breaks up her laying, divides it into series as +short as the room at her disposal demands; and each series begins +with females and ends with males. This breaking up, on the one hand, +into sections in all of which both sexes are represented and the +division, on the other hand, of the entire laying into just two +groups, one female, the other male, when the length of the tube +permits, surely provide us with ample evidence of the insect's power +to regulate the sex of the egg according to the exigencies of space. + +And besides the exigencies of space one might perhaps venture to add +those connected with the earlier development of the males. These +burst their cocoons a couple of weeks or more before the females; +they are the first who hasten to the sweets of the almond-tree. In +order to release themselves and emerge into the glad sunlight without +disturbing the string of cocoons wherein their sisters are still +sleeping, they must occupy the upper end of the row; and this, no +doubt, is the reason that makes the Osmia end each of her broken +layings with males. Being next to the door, these impatient ones will +leave the home without upsetting the shells that are slower in +hatching. + +I experimented on Latreille's Osmia, using short and even very short +stumps of reed. All that I had to do was to lay them just beside the +nests of the Mason-bee of the Sheds, nests beloved by this particular +Osmia. Old, disused hurdles supplied me with reeds inhabited from end +to end by the Horned Osmia. In both cases I obtained the same results +and the same conclusions as with the Three-horned Osmia. + +I return to the latter, nidifying under my eyes in some old nests of +the Mason-bee of the Walls, which I had placed within her reach, +mixed up with the tubes. Outside my study, I had never yet seen the +Three-horned Osmia adopt that domicile. This may be due to the fact +that these nests are isolated one by one in the fields; and the +Osmia, who loves to feel herself surrounded by her kin and to work in +plenty of company, refuses them because of this isolation. But on my +table, finding them close to the tubes in which the others are +working, she adopts them without hesitation. + +The chambers presented by those old nests are more or less spacious +according to the thickness of the coat of mortar which the +Chalicodoma has laid over the assembled chambers. To leave her cell, +the Mason-bee has to perforate not only the plug, the lid built at +the mouth of the cell, but also the thick plaster wherewith the dome +is strengthened at the end of the work. The perforation results in a +vestibule which gives access to the chamber itself. It is this +vestibule which is sometimes longer and sometimes shorter, whereas +the corresponding chamber is of almost constant dimensions, in the +case of the same sex, of course. + +We will first consider the short vestibule, at the most large enough +to receive the plug with which the Osmia will close up the lodging. +There is then nothing at her disposal except the cell proper, a +spacious apartment in which one of the Osmia's females will find +ample accommodation, for she is much smaller than the original +occupant of the chamber, no matter the sex; but there is not room for +two cocoons at a time, especially in view of the space taken up by +the intervening partition. Well, in those large, well-built chambers, +formerly the homes of Chalicodomae, the Osmia settles females and +none but females. + +Let us now consider the long vestibule. Here, a partition is +constructed, encroaching slightly on the cell proper, and the +residence is divided into two unequal storeys, a large room below, +housing a female, and a narrow cabin above, containing a male. + +When the length of the vestibule permits, allowing for the space +required by the outer stopper, a third storey is built, smaller than +the second; and another male is lodged in this cramped corner. In +this way the old nest of the Mason-bee of the Pebbles is colonized, +cell after cell, by a single mother. + +The Osmia, as we see, is very frugal of the lodging that has fallen +to her share; she makes the best possible use of it, giving to the +females the spacious chambers of the Mason-bee and to the males the +narrow vestibules, subdivided into storeys when this is feasible. +Economy of space is the chief consideration, since her stay-at-home +tastes do not allow her to indulge in distant quests. She has to +employ the site which chance places at her disposal just as it is, +now for a male and now for a female. Here we see displayed, more +clearly than ever, her power of deciding the sex of the egg, in order +to adapt it judiciously to the conditions of the house-room +available. + +I had offered at the same time to the Osmiae in my study some old +nests of the Mason-bee of the Shrubs, which are clay spheroids with +cylindrical cavities in them. These cavities are formed, as in the +old nests of the Mason-bee of the Pebbles, of the cell properly so- +called and of the exit-way which the perfect insect cut through the +outer coating at the time of its deliverance. Their diameter is about +seven millimetres (.273 inch.--Translator's Note.); their depth at +the centre of the heap is 23 millimetres (.897 inch.--Translator's +Note.); and at the edge averages 14 millimetres (.546 inch.-- +Translator's Note.) + +The deep central cells receive only the females of the Osmia; +sometimes even the two sexes together, with a partition in the +middle, the female occupying the lower and the male the upper storey. +True, in such cases economy of space is strained to the utmost, the +apartments provided by the Mason-bee of the Shrubs being very small +as it is, despite their entrance-halls. Lastly, the deeper cavities +on the circumference are allotted to females and the shallower to +males. + +I will add that a single mother peoples each nest and also that she +proceeds from cell to cell without troubling to ascertain the depth. +She goes from the centre to the edges, from the edges to the centre, +from a deep cavity to a shallow cavity and vice versa, which she +would not do if the sexes were to follow upon each other in a settled +order. For greater certainty, I numbered the cells of one nest as +each of them was closed. On opening them later, I was able to see +that the sexes were not subjected to a chronological arrangement. +Females were succeeded by males and these by females without its +being possible for me to make out any regular sequence. Only--and +this is the essential point--the deep cavities were allotted to the +females and the shallow ones to the males. + +We know that the Three-horned Osmia prefers to haunt the habitations +of the Bees who nidify in populous colonies, such as the Mason-bee of +the Sheds and the Hairy-footed Anthophora. Exercising the very +greatest care, I broke up some great lumps of earth removed from the +banks inhabited by the Anthophora and sent to me from Carpentras by +my dear friend and pupil M. Devillario. I examined them +conscientiously in the quiet of my study. I found the Osmia's cocoons +arranged in short series, in very irregular passages, the original +work of which is due to the Anthophora. Touched up afterwards, made +larger or smaller, lengthened or shortened, intersected with a +network of crossings by the numerous generations that had succeeded +one another in the same city, they formed an inextricable labyrinth. + +Sometimes these corridors did not communicate with any adjoining +apartment; sometimes they gave access to the spacious chamber of the +Anthophora, which could be recognized, in spite of its age, by its +oval shape and its coating of glazed stucco. In the latter case, the +bottom cell, which once constituted, by itself, the chamber of the +Anthophora, was always occupied by a female Osmia. Beyond it, in the +narrow corridor, a male was lodged, not seldom two, or even three. Of +course, clay partitions, the work of the Osmia, separated the +different inhabitants, each of whom had his own storey, his own +closed cell. + +When the accommodation consisted of no more than a simple cylinder, +with no state-bedroom at the end of it--a bedroom always reserved for +a female--the contents varied with the diameter of the cylinder. The +series, of which the longest were series of four, included, with a +wider diameter, first one or two females, then one or two males. It +also happened, though rarely, that the series was reversed, that is +to say, it began with males and ended with females. Lastly, there +were a good many isolated cocoons, of one sex or the other. When the +cocoon was alone and occupied the Anthophora's cell, it invariably +belonged to a female. + +I have observed the same thing in the nests of the Mason-bee of the +Sheds, but not so easily. The series are shorter here, because the +Mason-bee does not bore galleries but builds cell upon cell. The work +of the whole swarm thus forms a stratum of cells that grows thicker +from year to year. The corridors occupied by the Osmia are the holes +which the Mason-bee dug in order to reach daylight from the deep +layers. In these short series, both sexes are usually present; and, +if the Mason-bee's chamber is at the end of the passage, it is +inhabited by a female Osmia. + +We come back to what the short tubes and the old nests of the Mason- +bee of the Pebbles have already taught us. The Osmia who, in tubes of +sufficient length, divides her whole laying into a continuous +sequence of females and a continuous sequence of males, now breaks it +up into short series in which both sexes are present. She adapts her +sectional layings to the exigencies of a chance lodging; she always +places a female in the sumptuous chamber which the Mason-bee or the +Anthophora occupied originally. + +Facts even more striking are supplied by the old nests of the Masked +Anthophora (A. personata, ILLIG.), old nests which I have seen +utilized by the Horned Osmia and the Three-horned Osmia at the same +time. Less frequently, the same nests serve for Latreille's Osmia. +Let us first describe the Masked Anthophora's nests. + +In a steep bank of sandy clay, we find a set of round, wide-open +holes. There are generally only a few of them, each about half an +inch in diameter. They are the entrance-doors leading to the +Anthophora's abode, doors always left open, even after the building +is finished. Each of them gives access to a short passage, sometimes +straight, sometimes winding, nearly horizontal, polished with minute +care and varnished with a sort of white glaze. It looks as if it had +received a thin coat of whitewash. On the inner surface of this +passage, in the thickness of the earthy bank, spacious oval niches +have been excavated, communicating with the corridor by means of a +narrow bottle-neck, which is closed, when the work is done, with a +substantial mortar stopper. The Anthophora polishes the outside of +this stopper so well, smooths its surface so perfectly, bringing it +to the same level as that of the passage, is so careful to give it +the white tint of the rest of the wall that, when the job is +finished, it becomes absolutely impossible to distinguish the +entrance-door corresponding with each cell. + +The cell is an oval cavity dug in the earthy mass. The wall has the +same polish, the same chalky whiteness as the general passage. But +the Anthophora does not limit herself to digging oval niches: to make +her work more solid, she pours over the walls of the chamber a +salivary liquid which not only whitens and varnishes but also +penetrates to a depth of some millimetres into the sandy earth, which +it turns into a hard cement. A similar precaution is taken with the +passage; and therefore the whole is a solid piece of work capable of +remaining in excellent condition for years. + +Moreover, thanks to the wall hardened by the salivary fluid, the +structure can be removed from its matrix by chipping it carefully +away. We thus obtain, at least in fragments, a serpentine tube from +which hangs a single or double row of oval nodules that look like +large grapes drawn out lengthwise. Each of these nodules is a cell, +the entrance to which, carefully hidden, opens into the tube or +passage. When she wishes to leave her cell, in the spring, the +Anthophora destroys the mortar disk that closes the jar and thus +reaches the general corridor, which is quite open to the outer air. +The abandoned nest provides a series of pear-shaped cavities, of +which the distended part is the old cell and the contracted part the +exit-neck, rid of its stopper. + +These pear-shaped hollows form splendid lodgings, impregnable +strongholds, in which the Osmiae find a safe and commodious retreat +for their families. The Horned Osmia and the Three-horned Osmia +establish themselves there at the same time. Although it is a little +too large for her, Latrielle's Osmia also appears very well satisfied +with it. + +I have examined some forty of the superb cells utilized by each of +the first two. The great majority are divided into two storeys by +means of a transversal partition. The lower storey includes the +larger portion of the Anthophora's cell; the upper storey includes +the rest of the cell and a little of the bottle-neck that surmounts +it. The two-roomed dwelling is closed, in the passage, by a +shapeless, bulky mass of dried mud. What a clumsy artist the Osmia +is, compared with the Anthophora! Against the exquisite work of the +Anthophora, partition and plug strike a note as hideously incongruous +as a lump of dirt on polished marble. + +The two apartments thus obtained are of a very unequal capacity, +which at once strikes the observer. I measured them with my five- +millimetre tube. On an average, the bottom one is represented by a +column of sand 50 millimetres deep (1.95 inches.--Translator's Note.) +and the top one by a column of 15 millimetres (.585 inch.-- +Translator's Note.). The holding-capacity of the one is therefore +about three times as large as that of the other. The cocoons enclosed +present the same disparity. The bottom one is big, the top one small. +Lastly, the lower one belongs to a female Osmia and the upper to a +male Osmia. + +Occasionally the length of the bottle-neck allows of a fresh +arrangement and the cavity is divided into three storeys. The bottom +one, which is always the most spacious, contains a female; the two +above, both smaller than the first and one smaller than the other, +contain males. + +Let us keep to the first case, which is always the most frequent. The +Osmia is in the presence of one of these pear-shaped hollows. It is a +find that must be employed to the best advantage: a prize of this +sort is rare and falls only to fortune's favourites. To lodge two +females in it at once is impossible; there is not sufficient room. To +lodge two males in it would be undue generosity to a sex that is +entitled to but the smallest consideration. Besides, the two sexes +must be represented in almost equal numbers. The Osmia decides upon +one female, whose portion shall be the better room, the lower one, +which is larger, better-protected and more nicely polished, and one +male, whose portion shall be the upper storey, a cramped attic, +uneven and rugged in the part which encroaches on the bottle-neck. +This decision is proved by numerous undeniable facts. Both Osmiae +therefore can choose the sex of the egg about to be laid, seeing that +they are now breaking up the laying into groups of two, a female and +a male, as required by the conditions of the lodging. + +I have only once found Latreille's Osmia established in the nest of +the Masked Anthophora. She had occupied but a small number of cells, +because the others were not free, being inhabited by the Anthophora. +The cells in question were divided into three storeys by partitions +of green mortar; the lower storey was occupied by a female, the two +others by males, with smaller cocoons. + +I came to an even more remarkable example. Two Anthidia of my +district, A. septemdentatum, LATR., and A. bellicosum, LEP., adopt as +the home of their offspring the empty shells of different snails: +Helix aspersa, H. algira, H. nemoralis, H. caespitum. The first- +named, the Common Snail, is the most often used, under the stone- +heaps and in the crevices of old walls. Both Anthidia colonize only +the second whorl of the spiral. The central part is too small and +remains unoccupied. Even so with the front whorl, the largest, which +is left completely empty, so much so that, on looking through the +opening, it is impossible to tell whether the shell does or does not +contain the Bee's nest. We have to break this last whorl if we would +perceive the curious nest tucked away in the spiral. + +We then find first a transversal partition, formed of tiny bits of +gravel cemented by a putty made from resin, which is collected in +fresh drops from the oxycedrus and the Aleppo pine. Beyond this is a +stout barricade made up of rubbish of all kinds: bits of gravel, +scraps of earth, juniper-needles, the catkins of the conifers, small +shells, dried excretions of Snails. Next come a partition of pure +resin, a large cocoon in a roomy chamber, a second partition of pure +resin and, lastly, a smaller cocoon in a narrow chamber. The +inequality of the two cells is the necessary consequence of the shape +of the shell, whose inner space gains rapidly in width as the spiral +gets nearer to the orifice. Thus, by the mere general arrangement of +the home and without any work on the Bee's part beyond some slender +partitions, a large room is marked out in front and a much smaller +room at the back. + +By a very remarkable exception, which I have mentioned casually +elsewhere, the males of the genus Anthidium are generally larger than +the females; and this is the case with the two species in particular +that divide the Snail's spiral with resin partitions. I collected +some dozens of nests of both species. In at least half the cases, the +two sexes were present together; the female, the smaller, occupied +the front cell and the male, the bigger, the back cell. Other cells, +which were smaller or too much obstructed at the back by the dried-up +remains of the Mollusc, contained only one cell, occupied at one time +by a female and at another by a male. A few, lastly, had both cells +inhabited now by two males and now by two females. The most frequent +arrangement was the simultaneous presence of both sexes, with the +female in front and the male behind. The Anthidia who make resin- +dough and live in Snail-shells can therefore alternate the sexes +regularly to meet the exigencies of the spiral dwelling-house. + +One more thing and I have done. My apparatus of reeds, fixed against +the walls of the garden, supplied me with a remarkable nest of the +Horned Osmia. The nest is established in a bit of reed 11 millimetres +wide inside. (.429 inch--Translator's Note.) It comprises thirteen +cells and occupies only half the cylinder, although the orifice is +plugged with the usual stopper. The laying therefore seems here to be +complete. + +Well, this laying is arranged in a most singular fashion. There is +first, at a suitable distance from the bottom or the node of the +reed, a transversal partition, perpendicular to the axis of the tube. +This marks off a cell of unusual size, in which a female is lodged. +After that, in view of the excessive width of the tunnel, which is +too great for a series in single file, the Osmia appears to alter her +mind. She therefore builds a partition perpendicular to the +transversal partition which she has just constructed and thus divides +the second storey into two rooms, a larger room, in which she lodges +a female, and a smaller, in which she lodges a male. She next builds +a second transversal partition and a second longitudinal partition +perpendicular to it. These once more give two unequal chambers, +stocked likewise, the large one with a female, the smaller one with a +male. + +>From this third storey onwards, the Osmia abandons geometrical +accuracy; the architect seems to be a little out in her reckoning. +The transversal partitions become more and more slanting and the work +grows irregular, but always with a sprinkling of large chambers for +the females and small chambers for the males. Three females and two +males are housed in this way, the sexes alternating. + +By the time that the base of the eleventh cell is reached, the +transversal partition is once more almost perpendicular to the axis. +Here what happened at the bottom is repeated. There is no +longitudinal partition; and the spacious cell, covering the whole +diameter of the cylinder, receives a female. The edifice ends with +two transversal partitions and one longitudinal partition, which mark +out, on the same level, chambers twelve and thirteen, both of which +contain males. + +There is nothing more curious than this mixing of the two sexes, when +we know with what precision the Osmia separates them in a linear +series, where the narrow width of the cylinder demands that the cells +shall be set singly, one above the other. Here, the Bee is making use +of a tube whose diameter is not suited to her work; she is +constructing a complex and difficult edifice, which perhaps would not +possess the necessary solidity if the ceilings were too broad. The +Osmia therefore supports these ceilings with longitudinal partitions; +and the unequal chambers resulting from the introduction of these +partitions receive females at one time and males at another, +according to their capacity. + + +CHAPTER 5. PERMUTATIONS OF SEX. + +The sex of the egg is optional. The choice rests with the mother, who +is guided by considerations of space and, according to the +accommodation at her disposal, which is frequently fortuitous and +incapable of modification, places a female in this cell and a male in +that, so that both may have a dwelling of a size suited to their +unequal development. This is the unimpeachable evidence of the +numerous and varied facts which I have set forth. People unfamiliar +with insect anatomy--the public for whom I write--would probably give +the following explanation of this marvellous prerogative of the Bee: +the mother has at her disposal a certain number of eggs, some of +which are irrevocably female and the others irrevocably male: she is +able to pick out of either group the one which she wants at the +actual moment; and her choice is decided by the holding capacity of +the cell that has to be stocked. Everything would then be limited to +a judicious selection from the heap of eggs. + +Should this idea occur to him, the reader must hasten to reject it. +Nothing could be more false, as the merest reference to anatomy will +show. The female reproductive apparatus of the Hymenoptera consists +generally of six ovarian tubes, something like glove-fingers, divided +into bunches of three and ending in a common canal, the oviduct, +which carries the eggs outside. Each of these glove-fingers is fairly +wide at the base, but tapers sharply towards the tip, which is +closed. It contains, arranged in a row, one after the other, like +beads on a string, a certain number of eggs, five or six for +instance, of which the lower ones are more or less developed, the +middle ones half-way towards maturity, and the upper ones very +rudimentary. Every stage of evolution is here represented, +distributed regularly from bottom to top, from the verge of maturity +to the vague outlines of the embryo. The sheath clasps its string of +ovules so closely that any inversion of the order is impossible. +Besides, an inversion would result in a gross absurdity: the +replacing of a riper egg by another in an earlier stage of +development. + +Therefore, in each ovarian tube, in each glove-finger, the emergence +of the eggs occurs according to the order governing their arrangement +in the common sheath; and any other sequence is absolutely +impossible. Moreover, at the nesting period, the six ovarian sheaths, +one by one and each in its turn, have at their base an egg which in a +very short time swells enormously. Some hours or even a day before +the laying, that egg by itself represents or even exceeds in bulk the +whole of the ovigenous apparatus. This is the egg which is on the +point of being laid. It is about to descend into the oviduct, in its +proper order, at its proper time; and the mother has no power to make +another take its place. It is this egg, necessarily this egg and no +other, that will presently be laid upon the provisions, whether these +be a mess of honey or a live prey; it alone is ripe, it alone is at +the entrance to the oviduct; none of the others, since they are +farther back in the row and not at the right stage of development, +can be substituted at this crisis. Its birth is inevitable. + +What will it yield, a male or a female? No lodging has been prepared, +no food collected for it; and yet both food and lodging have to be in +keeping with the sex that will proceed from it. And here is a much +more puzzling condition: the sex of that egg, whose advent is +predestined, has to correspond with the space which the mother +happens to have found for a cell. There is therefore no room for +hesitation, strange though the statement may appear: the egg, as it +descends from its ovarian tube, has no determined sex. It is perhaps +during the few hours of its rapid development at the base of its +ovarian sheath, it is perhaps on its passage through the oviduct that +it receives, at the mother's pleasure, the final impress that will +produce, to match the cradle which it has to fill, either a female or +a male. + +Thereupon the following question presents itself. Let us admit that, +when the normal conditions remain, a laying would have yielded m +females and n males. Then, if my conclusions are correct, it must be +in the mother's power, when the conditions are different, to take +from the m group and increase the n group to the same extent; it must +be possible for her laying to be represented as m-1, m-2, m-3, etc. +females and by n+1, n+2, n+3, etc. males, the sum of m+n remaining +constant, but one of the sexes being partly permuted into the other. +The ultimate conclusion even cannot be disregarded: we must admit a +set of eggs represented by m-m, or zero, females and of n+m males, +one of the sexes being completely replaced by the other. Conversely, +it must be possible for the feminine series to be augmented from the +masculine series to the extent of absorbing it entirely. It was to +solve this question and some others connected with it that I +undertook, for the second time, to rear the Three-horned Osmia in my +study. + +The problem on this occasion is a more delicate one; but I am also +better-equipped. My apparatus consists of two small, closed packing- +cases, with the front side of each pierced with forty holes, in which +I can insert my glass tubes and keep them in a horizontal position. I +thus obtain for the Bees the darkness and mystery which suit their +work and for myself the power of withdrawing from my hive, at any +time, any tube that I wish, with the Osmia inside, so as to carry it +to the light and follow, if need be with the aid of the lens, the +operations of the busy worker. My investigations, however frequent +and minute, in no way hinder the peaceable Bee, who remains absorbed +in her maternal duties. + +I mark a plentiful number of my guests with a variety of dots on the +thorax, which enables me to follow any one Osmia from the beginning +to the end of her laying. The tubes and their respective holes are +numbered; a list, always lying open on my desk, enables me to note +from day to day, sometimes from hour to hour, what happens in each +tube and particularly the actions of the Osmiae whose backs bear +distinguishing marks. As soon as one tube is filled, I replace it by +another. Moreover, I have scattered in front of either hive a few +handfuls of empty Snail-shells, specially chosen for the object which +I have in view. Reasons which I will explain later led me to prefer +the shells of Helix caespitum. Each of the shells, as and when +stocked, received the date of the laying and the alphabetical sign +corresponding with the Osmia to whom it belonged. In this way, I +spent five or six weeks in continual observation. To succeed in an +enquiry, the first and foremost condition is patience. This condition +I fulfilled; and it was rewarded with the success which I was +justified in expecting. + +The tubes employed are of two kinds. The first, which are cylindrical +and of the same width throughout, will be of use for confirming the +facts observed in the first year of my experiments in indoor rearing. +The others, the majority, consist of two cylinders which are of very +different diameters, set end to end. The front cylinder, the one +which projects a little way outside the hive and forms the entrance- +hole, varies in width between 8 and 12 millimetres. (Between .312 to +.468 inch.--Translator's Note.) The second, the back one, contained +entirely within my packing-case, is closed at its far end and is 5 to +6 millimetres (.195 to .234 inch.--Translator's Note.) in diameter. +Each of the two parts of the double-galleried tunnel, one narrow and +one wide, measures at most a decimetre (3.9 inches.--Translator's +Note.) in length. I thought it advisable to have these short tubes, +as the Osmia is thus compelled to select different lodgings, each of +them being insufficient in itself to accommodate the total laying. In +this way I shall obtain a greater variety in the distribution of the +sexes. Lastly, at the mouth of each tube, which projects slightly +outside the case, there is a little paper tongue, forming a sort of +perch on which the Osmia alights on her arrival and giving easy +access to the house. With these facilities, the swarm colonized +fifty-two double-galleried tubes, thirty-seven cylindrical tubes, +seventy-eight Snail-shells and a few old nests of the Mason-bee of +the Shrubs. From this rich mine of material I will take what I want +to prove my case. + +Every series, even when incomplete, begins with females and ends with +males. To this rule I have not yet found an exception, at least in +galleries of normal diameter. In each new abode, the mother busies +herself first of all with the more important sex. Bearing this point +in mind, would it be possible for me, by manoeuvring, to obtain an +inversion of this order and make the laying begin with males? I think +so, from the results already ascertained and the irresistible +conclusions to be drawn from them. The double-galleried tubes are +installed in order to put my conjectures to the proof. + +The back gallery, 5 or 6 millimetres (.195 to .234 inch.-- +Translator's Note.) wide, is too narrow to serve as a lodging for +normally developed females. If, therefore, the Osmia, who is very +economical of her space, wishes to occupy them, she will be obliged +to establish males there. And her laying must necessarily begin here, +because this corner is the rear-most part of the tube. The foremost +gallery is wide, with an entrance-door on the front of the hive. +Here, finding the conditions to which she is accustomed, the mother +will go on with her laying in the order which she prefers. + +Let us now see what has happened. Of the fifty-two double galleried +tubes, about a third did not have their narrow passage colonized. The +Osmia closed its aperture communicating with the large passage; and +the latter alone received the eggs. This waste of space was +inevitable. The female Osmiae, though nearly always larger than the +males, present marked differences among one another: some are bigger, +some are smaller. I had to adjust the width of the narrow galleries +to Bees of average dimensions. It may happen therefore that a gallery +is too small to admit the large-sized mothers to whom chance allots +it. When the Osmia is unable to enter the tube, obviously she will +not colonize it. She then closes the entrance to this space which she +cannot use and does her laying beyond it, in the wide tube. Had I +tried to avoid these useless apparatus by choosing tubes of larger +calibre, I should have encountered another drawback: the medium-sized +mothers, finding themselves almost comfortable, would have decided to +lodge females there. I had to be prepared for it: as each mother +selected her house at will and as I was unable to interfere in her +choice, a narrow tube would be colonized or not, according as the +Osmia who owned it was or was not able to make her way inside. + +There remain some forty pairs of tubes with both galleries colonized. +In these there are two things to take into consideration. The narrow +rear tubes of 5 or 5 1/2 millimetres (.195 to .214 inch.-- +Translator's Note.)--and these are the most numerous--contain males +and males only, but in short series, between one and five. The mother +is here so much hampered in her work that they are rarely occupied +from end to end; the Osmia seems in a hurry to leave them and to go +and colonize the front tube, whose ample space will leave her the +liberty of movement necessary for her operations. The other rear +tubes, the minority, whose diameter is about 6 millimetres (.234 +inch.--Translator's Note.), contain sometimes only females and +sometimes females at the back and males towards the opening. One can +see that a tube a trifle wider and a mother slightly smaller would +account for this difference in the results. Nevertheless, as the +necessary space for a female is barely provided in this case, we see +that the mother avoids as far as she can a two-sex arrangement +beginning with males and that she adopts it only in the last +extremity. Finally, whatever the contents of the small tube may be, +those of the large one, following upon it, never vary and consist of +females at the back and males in front. + +Though incomplete, because of circumstances very difficult to +control, the result of the experiment is none the less very striking. +Twenty-five apparatus contain only males in their narrow gallery, in +numbers varying from a minimum of one to a maximum of five. After +these comes the colony of the large gallery, beginning with females +and ending with males. And the layings in these apparatus do not +always belong to late summer or even to the intermediate period: a +few small tubes contain the earliest eggs of the Osmiae. A couple of +Osmiae, more forward than the others, set to work on the 23rd of +April. Both of them started their laying by placing males in the +narrow tubes. The meagre supply of provisions was enough in itself to +show the sex, which proved later to be in accordance with my +anticipations. We see then that, by my artifices, the whole swarm +starts with the converse of the normal order. This inversion is +continued, at no matter what period, from the beginning to the end of +the operations. The series which, according to rule, would begin with +females now begins with males. Once the larger gallery is reached, +the laying is pursued in the usual order. + +We have advanced one step and that no small one: we have seen that +the Osmia, when circumstances require it, is capable of reversing the +sequence of the sexes. Would it be possible, provided that the tube +were long enough, to obtain a complete inversion, in which the entire +series of the males should occupy the narrow gallery at the back and +the entire series of the females the roomy gallery in front? I think +not; and I will tell you why. + +Long and narrow cylinders are by no means to the Osmia's taste, not +because of their narrowness but because of their length. Remember +that for each load of honey brought the worker is obliged to move +backwards twice. She enters, head first, to begin by disgorging the +honey-syrup from her crop. Unable to turn in a passage which she +blocks entirely, she goes out backwards, crawling rather than +walking, a laborious performance on the polished surface of the glass +and a performance which, with any other surface, would still be very +awkward, as the wings are bound to rub against the wall with their +free end and are liable to get rumpled or bent. She goes out +backwards, reaches the outside, turns round and goes in again, but +this time the opposite way, so as to brush off the load of pollen +from her abdomen on to the heap. If the gallery is at all long, this +crawling backwards becomes troublesome after a time; and the Osmia +soon abandons a passage that is too small to allow of free movement. +I have said that the narrow tubes of my apparatus are, for the most +part, only very incompletely colonized. The Bee, after lodging a +small number of males in them, hastens to leave them. In the wide +front gallery, she can stay where she is and still be able to turn +round easily for her different manipulations; she will avoid those +two long journeys backwards, which are so exhausting and so bad for +her wings. + +Another reason no doubt prompts her not to make too great a use of +the narrow passage, in which she would establish males, followed by +females in the part where the gallery widens. The males have to leave +their cells a couple of weeks or more before the females. If they +occupy the back of the house, they will die prisoners or else they +will overturn everything on their way out. This risk is avoided by +the order which the Osmia adopts. + +In my tubes with their unusual arrangement, the mother might well +find the dilemma perplexing: there is the narrowness of the space at +her disposal and there is the emergence later on. In the narrow +tubes, the width is insufficient for the females; on the other hand, +if she lodges males there, they are liable to perish, since they will +be prevented from issuing at the proper moment. This would perhaps +explain the mother's hesitation and her obstinacy in settling females +in some of my apparatus which looked as if they could suit none but +males. + +A suspicion occurs to me, a suspicion aroused by my attentive +examination of the narrow tubes. All, whatever the number of their +inmates, are carefully plugged at the opening, just as separate tubes +would be. It might therefore be the case that the narrow gallery at +the back was looked upon by the Osmia not as the prolongation of the +large front gallery, but as an independent tube. The facility with +which the worker turns as soon as she reaches the wide tube, her +liberty of action, which is now as great as in a doorway +communicating with the outer air, might well be misleading and cause +the Osmia to treat the narrow passage at the back as though the wide +passage in front did not exist. This would account for the placing of +the female in the large tube above the males in the small tube, an +arrangement contrary to her custom. + +I will not undertake to decide whether the mother really appreciates +the danger of my snares, or whether she makes a mistake in +considering only the space at her disposal and beginning with males. +At any rate, I perceive in her a tendency to deviate as little as +possible from the order which safeguards the emergence of the two +sexes. This tendency is demonstrated by her repugnance to colonizing +my narrow tubes with long series of males. However, so far as we are +concerned, it does not matter much what passes at such times in the +Osmia's little brain. Enough for us to know that she dislikes narrow +and long tubes, not because they are narrow, but because they are at +the same time long. + +And, in fact, she does very well with a short tube of the same +diameter. Such are the cells in the old nests of the Mason-bee of the +Shrubs and the empty shells of the Garden Snail. With the short tube, +the two disadvantages of the long tube are avoided. She has very +little of that crawling backwards to do when she has a Snail-shell +for the home of her eggs and scarcely any when the home is the cell +of the Mason-bee. Moreover, as the stack of cocoons numbers two or +three at most, the deliverance will be exempt from the difficulties +attached to a long series. To persuade the Osmia to nidify in a +single tube long enough to receive the whole of her laying and at the +same time narrow enough to leave her only just the possibility of +admittance appears to me a project without the slightest chance of +success: the Bee would stubbornly refuse such a dwelling or would +content herself with entrusting only a very small portion of her eggs +to it. On the other hand, with narrow but short cavities, success, +without being easy, seems to me at least quite possible. Guided by +these considerations, I embarked upon the most arduous part of my +problem: to obtain the complete or almost complete permutation of one +sex with the other; to produce a laying consisting only of males by +offering the mother a series of lodgings suited only to males. + +Let us in the first place consult the old nests of the Mason-bee of +the Shrubs. I have said that these mortar spheroids, pierced all over +with little cylindrical cavities, are adopted pretty eagerly by the +Three-horned Osmia, who colonizes them before my eyes with females in +the deep cells and males in the shallow cells. That is how things go +when the old nest remains in its natural state. With a grater, +however, I scrape the outside of another nest so as to reduce the +depth of the cavities to some ten millimetres. (About two-fifths of +an inch.--Translator's Note.) This leaves in each cell just room for +one cocoon, surmounted by the closing stopper. Of the fourteen +cavities in the nests, I leave two intact, measuring fifteen +millimetres in depth. (.585 inch.--Translator's Note.) Nothing could +be more striking than the result of this experiment, made in the +first year of my home rearing. The twelve cavities whose depth had +been reduced all received males; the two cavities left untouched +received females. + +A year passes and I repeat the experiment with a nest of fifteen +cells; but this time all the cells are reduced to the minimum depth +with the grater. Well, the fifteen cells, from first to last, are +occupied by males. It must be quite understood that, in each case, +all the offspring belonged to one mother, marked with her +distinguishing spot and kept in sight as long as her laying lasted. +He would indeed be difficult to please who refused to bow before the +results of these two experiments. If, however, he is not yet +convinced, here is something to remove his last doubts. + +The Three-horned Osmia often settles her family in old shells, +especially those of the Common Snail (Helix aspersa), who is so +common under the stone-heaps and in the crevices of the little +unmortared walls that support our terraces. In this species, the +spiral is wide open, so that the Osmia, penetrating as far down as +the helical passage permits, finds, immediately above the point which +is too narrow to pass, the space necessary for the cell of a female. +This cell is succeeded by others, wider still, always for females, +arranged in a line in the same way as in a straight tube. In the last +whorl of the spiral, the diameter would be too great for a single +row. Then longitudinal partitions are added to the transverse +partitions, the whole resulting in cells of unequal dimensions in +which males predominate, mixed with a few females in the lower +storeys. The sequence of the sexes is therefore what it would be in a +straight tube and especially in a tube with a wide bore, where the +partitioning is complicated by subdivisions on the same level. A +single Snail-shell contains room for six or eight cells. A large, +rough earthen stopper finishes the nest at the entrance to the shell. + +As a dwelling of this sort could show us nothing new, I chose for my +swarm the Garden Snail (Helix caespitum), whose shell, shaped like a +small, swollen Ammonite, widens by slow degrees, the diameter of the +usable portion, right up to the mouth, being hardly greater than that +required by a male Osmia-cocoon. Moreover, the widest part, in which +a female might find room, has to receive a thick stopping-plug, below +which there will often be a free space. Under all these conditions, +the house will hardly suit any but males arranged one after the +other. + +The collection of shells placed at the foot of each hive includes +specimens of different sizes. The smallest are 18 millimetres (.7 +inch.--Translator's Note.) in diameter and the largest 24 millimetres +(.936 inch.--Translator's Note.) There is room for two cocoons, or +three at most, according to their dimensions. + +Now these shells were used by my visitors without any hesitation, +perhaps even with more eagerness than the glass tubes, whose slippery +sides might easily be a little annoying to the Bee. Some of them were +occupied on the first few days of the laying; and the Osmia who had +started with a home of this sort would pass next to a second Snail- +shell, in the immediate neighbourhood of the first, to a third, a +fourth and others still, always close to one another, until her +ovaries were emptied. The whole family of one mother would thus be +lodged in Snail-shells which were duly marked with the date of the +laying and a description of the worker. The faithful adherents of the +Snail-shell were in the minority. The greater number left the tubes +to come to the shells and then went back from the shells to the +tubes. All, after filling the spiral staircase with two or three +cells, closed the house with a thick earthen stopper on a level with +the opening. It was a long and troublesome task, in which the Osmia +displayed all her patience as a mother and all her talents as a +plasterer. There were even some who, scrupulous to excess, carefully +cemented the umbilicus, a hole which seemed to inspire them with +distrust as being able to give access to the interior of the +dwelling. It was a dangerous-looking cavity, which for the greater +safety of the family it was prudent to block up. + +When the pupae are sufficiently matured, I proceed to examine these +elegant abodes. The contents fill me with joy: they fulfil my +anticipations to the letter. The great, the very great majority of +the cocoons turn out to be males; here and there, in the bigger +cells, a few rare females appear. The smallness of the space has +almost done away with the sixty-eight Snail-shells colonized. But, of +this total number, I must use only those series which received an +entire laying and were occupied by the same Osmia from the beginning +to the end of the egg-season. Here are a few examples, taken from +among the most conclusive. + +>From the 6th of May, when she started operations, to the 25th of May, +the date at which her laying ceased, the Osmia occupied seven Snail- +shells in succession. Her family consists of fourteen cocoons, a +number very near the average; and, of these fourteen cocoons, twelve +belong to males and only two to females. These occupy the seventh and +thirteenth places in chronological order. + +Another, between the 9th and 27th of May, stocked six Snail-shells +with a family of thirteen, including ten males and three females. The +places occupied by the latter in the series were numbers 3, 4 and 5. + +A third, between the 2nd and 29th of May, colonized eleven Snail- +shells, a prodigious task. This industrious one was also exceedingly +prolific. She supplied me with a family of twenty-six, the largest +which I have ever obtained from one Osmia. Well, this abnormal +progeny consisted of twenty-five males and one female, one alone, +occupying place 17. + +There is no need to go on, after this magnificent example, especially +as the other series would all, without exception, give us the same +result. Two facts are immediately obvious. The Osmia is able to +reverse the order of her laying and to start with a more or less long +series of males before producing any females. In the first case, the +first female appears as number 7; in the third, as number 17. There +is something better still; and this is the proposition which I was +particularly anxious to prove: the female sex can be permuted with +the male sex and can be permuted to the point of disappearing +altogether. We see this especially in the third case, where the +presence of a solitary female in a family of twenty-six is due to the +somewhat larger diameter of the corresponding Snail-shell and also, +no doubt, to some mistake on the mother's part, for the female +cocoon, in a series of two, occupies the upper storey, the one next +to the orifice, an arrangement which the Osmia appears to me to +dislike. + +This result throws so much light on one of the darkest corners of +biology that I must attempt to corroborate it by means of even more +conclusive experiments. I propose next year to give the Osmiae +nothing but Snail-shells for a lodging, picked out one by one, and +rigorously to deprive the swarm of any other retreat in which the +laying could be effected. Under these conditions, I ought to obtain +nothing but males, or nearly, for the whole swarm. + +There would still remain the inverse permutation: to obtain only +females and no males, or very few. The first permutation makes the +second seem very probable, although I cannot as yet conceive a means +of realizing it. The only condition which I can regulate is the +dimensions of the home. When the rooms are small, the males abound +and the females tend to disappear. With generous quarters, the +converse would not take place. I should obtain females and afterwards +an equal number of males, confined in small cells which, in case of +need, would be bounded by numerous partitions. The factor of space +does not enter into the question here. What artifice can we then +employ to provoke this second permutation? So far, I can think of +nothing that is worth attempting. + +It is time to conclude. Leading a retired life, in the solitude of a +village, having quite enough to do with patiently and obscurely +ploughing my humble furrow, I know little about modern scientific +views. In my young days I had a passionate longing for books and +found it difficult to procure them; to-day, when I could almost have +them if I wanted, I am ceasing to wish for them. It is what usually +happens as life goes on. I do not therefore know what may have been +done in the direction whither this study of the sexes has led us. If +I am stating propositions that are really new or at least more +comprehensive than the propositions already known, my words will +perhaps sound heretical. No matter: as a simple translator of facts, +I do not hesitate to make my statement, being fully persuaded that +time will turn my heresy into orthodoxy. I will therefore +recapitulate my conclusions. + +Bees lay their eggs in series of first females and then males, when +the two sexes are of different sizes and demand an unequal quantity +of nourishment. When the two sexes are alike in size, the same +sequence may occur, but less regularly. + +This dual arrangement disappears when the place chosen for the nest +is not large enough to contain the entire laying. We then see broken +layings, beginning with females and ending with males. + +The egg, as it issues from the ovary, has not yet a fixed sex. The +final impress that produces the sex is given at the moment of laying +or a little before. + +So as to be able to give each larva the amount of space and food that +suits it according as it is male or female, the mother can choose the +sex of the egg which she is about to lay. To meet the conditions of +the building, which is often the work of another or else a natural +retreat that admits of little or no alteration, she lays either a +male egg or a female egg as she pleases. The distribution of the +sexes depends upon herself. Should circumstances require it, the +order of the laying can be reversed and begin with males; lastly, the +entire laying can contain only one sex. + +The same privilege is possessed by the predatory Hymenoptera, the +Wasps, at least by those in whom the two sexes are of a different +size and consequently require an amount of nourishment that is larger +in the one case than in the other. The mother must know the sex of +the egg which she is going to lay; she must be able to choose the sex +of that egg so that each larva may obtain its proper portion of food. + +Generally speaking, when the sexes are of different sizes, every +insect that collects food and prepares or selects a dwelling for its +offspring must be able to choose the sex of the egg in order to +satisfy without mistake the conditions imposed upon it. + +The question remains how this optional assessment of the sexes is +effected. I know absolutely nothing about it. If I should ever learn +anything about this delicate point, I shall owe it to some happy +chance for which I must wait, or rather watch, patiently. Towards the +end of my investigations, I heard of a German theory which relates to +the Hive-bee and comes from Dzierzon, the apiarist. (Johann Dzierzon, +author of "Theorie und Praxis des neuen Bienenfreundes."-- +Translator's Note.) If I understand it aright, according to the very +incomplete documents which I have before me, the egg, as it issues +from the ovary, is said already to possess a sex, which is always the +same; it is originally male; and it becomes female by fertilization. +The males are supposed to proceed from non-fertilized eggs, the +females from fertilized eggs. The Queen-bee would thus lay female +eggs or male eggs according as she fertilized them or not while they +were passing into her oviduct. + +Coming from Germany, this theory cannot but inspire me with profound +distrust. As it has been given acceptance, with rash precipitancy, in +standard works, I will overcome my reluctance to devoting my +attention to Teutonic ideas and will submit it not to the test of +argument, which can always be met by an opposite argument, but to the +unanswerable test of facts. + +For this optional fertilization, determining the sex, the mother's +organism requires a seminal reservoir which distils its drop of sperm +upon the egg contained in the oviduct and thus gives it a feminine +character, or else leaves it its original character, the male +character, by refusing it that baptism. This reservoir exists in the +Hive-bee. Do we find a similar organ in the other Hymenoptera, +whether honey-gatherers or hunters? The anatomical treatises are +either silent on this point or, without further enquiry, apply to the +order as a whole the data provided by the Hive-bee, however much she +differs from the mass of Hymenoptera owing to her social habits, her +sterile workers and especially her tremendous fertility, extending +over so long a period. + +I at first doubted the universal presence of this spermatic +receptacle, having failed to find it under my scalpel in my former +investigations into the anatomy of the Sphex-wasps and some other +game-hunters. But this organ is so delicate and so small that it very +easily escapes the eye, especially when our attention is not +specially directed in search of it; and, even when we are looking for +it and it only, we do not always succeed in discovering it. We have +to find a globule attaining in many cases hardly as much as a +millimetre (About one-fiftieth of an inch.--Translator's Note.) in +diameter, a globule headed amidst a tangle of air-ducts and fatty +patches, of which it shares the colour, a dull white. Then again, the +merest slip of the forceps is enough to destroy it. My first +investigations, therefore, which concerned the reproductive apparatus +as a whole, might very well have allowed it to pass unperceived. + +In order to know the rights of the matter once and for all, as the +anatomical treatises taught me nothing, I once more fixed my +microscope on its stand and rearranged my old dissecting-tank, an +ordinary tumbler with a cork disk covered with black satin. This +time, not without a certain strain on my eyes, which are already +growing tired, I succeeded in finding the said organ in the Bembex- +wasps, the Halicti (Cf. Chapters 12 to 14 of the present volume.-- +Translator's Note.), the Carpenter-bees, the Bumble-bees, the +Andrenae (A species of Burrowing Bees.--Translator's Note.) and the +Megachiles. (Or Leaf-cutting Bees. Cf. Chapter 8 of the present +volume.--Translator's Note.) I failed in the case of the Osmiae, the +Chalicodomae and the Anthophorae. Is the organ really absent? Or was +there want of skill on my part? I lean towards want of skill and +admit that all the game-hunting and honey-gathering Hymenoptera +possess a seminal receptacle, which can be recognized by its +contents, a quantity of spiral spermatozoids whirling and twisting on +the slide of the microscope. + +This organ once accepted, the German theory becomes applicable to all +the Bees and all the Wasps. When copulating, the female receives the +seminal fluid and holds it stored in her receptacle. From that +moment, the two procreating elements are present in the mother at one +and the same time: the female element, the ovule; and the male +element, the spermatozoid. At the egg-layer's will, the receptacle +bestows a tiny drop of its contents upon the matured ovule, when it +reaches the oviduct, and you have a female egg; or else it withholds +its spermatozoids and you have an egg that remains male, as it was at +first. I readily admit it: the theory is very simple, lucid and +seductive. But is it correct? That is another question. + +One might begin by reproaching it with making a singular exception to +one of the most general rules. Which of us, casting his eyes over the +whole zoological progression, would dare to assert that the egg is +originally male and that it becomes female by fertilization? Do not +the two sexes both call for the assistance of the fertilizing +element? If there be one undoubted truth, it is certainly that. We +are, it is true, told very curious things about the Hive-bee. I will +not discuss them: this Bee stands too far outside the ordinary +limits; and then the facts asserted are far from being accepted by +everybody. But the non-social Bees and the predatory insects have +nothing special about their laying. Then why should they escape the +common rule, which requires that every living creature, male as well +as female, should come from a fertilized ovule? In its most solemn +act, that of procreation, life is one and uniform; what it does here +it does there and there and everywhere. What! The sporule of a scrap +of moss requires an antherozoid before it is fit to germinate; and +the ovule of a Scolia, that proud huntress, can dispense with the +equivalent in order to hatch and produce a male? These new-fangled +theories seem to me to have very little value. + +One might also bring forward the case of the Three-pronged Osmia, who +distributes the two sexes without any order in the hollow of her +reed. What singular whim is the mother obeying when, without decisive +motive, she opens her seminal phial at haphazard to anoint a female +egg, or else keeps it closed, also at haphazard, to allow a male egg +to pass unfertilized? I could imagine impregnation being given or +withheld for periods of some duration; but I cannot understand +impregnation and non-impregnation following upon each other anyhow, +in any sort of order, or rather with no order it all. The mother has +just fertilized an egg. Why should she refuse to fertilize the next, +when neither the provisions nor the lodgings differ in the smallest +respect from the previous provisions and lodgings? These capricious +alternations, so unreasonable and so exceedingly erratic, are +scarcely appropriate to an act of such importance. + +But I promised not to argue and I find myself arguing. My reasoning +is too fine for dull wits. I will pass on and come to the brutal +fact, the real sledge-hammer blow. + +Towards the end of the Bee's operations, in the first week of June, +the last acts of the Three-horned Osmia become so exceptionally +interesting that I made her the object of redoubled observation. The +swarm at this time is greatly reduced in numbers. I have still some +thirty laggards, who continue very busy, though their work is in +vain. I see some very conscientiously stopping up the entrance to a +tube or a Snail-shell in which they have laid nothing at all. Others +are closing the home after only building a few partitions, or even +mere attempts at partitions. Some are placing at the back of a new +gallery a pinch of pollen which will benefit nobody and then shutting +up the house with an earthen stopper as thick, as carefully made as +though the safety of a family depended on it. Born a worker, the +Osmia must die working. When her ovaries are exhausted, she spends +the remainder of her strength on useless works: partitions, plugs, +pollen-heaps, all destined to be left unemployed. The little animal +machine cannot bring itself to be inactive even when there is nothing +more to be done. It goes on working so that its last vibrations of +energy may be used up in fruitless labour. I commend these +aberrations to the staunch supporters of reasoning-powers in the +animal. + +Before coming to these useless tasks, my laggards have laid their +last eggs, of which I know the exact cells, the exact dates. These +eggs, as far as the microscopes can tell, differ in no respect from +the others, the older ones. They have the same dimensions, the same +shape, the same glossiness, the same look of freshness. Nor are their +provisions in any way peculiar, being very well suited to the males, +who conclude the laying. And yet these last eggs do not hatch: they +wrinkle, fade and wither on the pile of food. In one case, I count +three or four sterile eggs among the last lot laid; in another, I +find two or only one. Elsewhere in the swarm, fertile eggs have been +laid right up to the end. + +Those sterile eggs, stricken with death at the moment of their birth, +are too numerous to be ignored. Why do they not hatch like the other +eggs, which outwardly they resemble in every respect? They have +received the same attention from the mother and the same portion of +food. The searching microscope shows me nothing in them to explain +the fatal ending. + +To the unprejudiced mind, the answer is obvious. Those eggs do not +hatch because they have not been fertilized. Any animal or vegetable +egg that had not received the life-giving impregnation would perish +in the same way. No other answer is possible. It is no use talking of +the distant period of the laying: eggs of the same period laid by +other mothers, eggs of the same date and likewise the final ones of a +laying, are perfectly fertile. Once more, they do not hatch because +they were not fertilized. + +And why were they not fertilized? Because the seminal receptacle, so +tiny, so difficult to see that it sometimes escaped me despite all my +scrutiny, had exhausted its contents. The mothers in whom this +receptacle retained a remnant of sperm to the end had their last eggs +as fertile as the first; the others, whose seminal reservoir was +exhausted too soon, had their last-born stricken with death. All this +seems to me as clear as daylight. + +If the unfertilized eggs perish without hatching, those which hatch +and produce males are therefore fertilized; and the German theory +falls to the ground. + +Then what explanation shall I give of the wonderful facts which I +have set forth? Why, none, absolutely none. I do not explain facts, I +relate them. Growing daily more sceptical of the interpretations +suggested to me and more hesitating as to those which I may have to +suggest myself, the more I observe and experiment, the more clearly I +see rising out of the black mists of possibility an enormous note of +interrogation. + +Dear insects, my study of you has sustained me and continues to +sustain me in my heaviest trials. I must take leave of you for +to-day. The ranks are thinning around me and the long hopes have +fled. Shall I be able to speak to you again? (This is the closing +paragraph of Volume 3 of the "Souvenirs entomologiques," of which the +author has lived to publish seven more volumes, containing over 2,500 +pages and nearly 850,000 words.--Translator's Note.) + + +CHAPTER 6. INSTINCT AND DISCERNMENT. + +The Pelopaeus (A Mason-wasp forming the subject of essays which have +not yet been published in English.--Translator's Note.) gives us a +very poor idea of her intellect when she plasters up the spot in the +wall where the nest which I have removed used to stand, when she +persists in cramming her cell with Spiders for the benefit of an egg +no longer there and when she dutifully closes a cell which my forceps +has left empty, extracting alike germ and provisions. The Mason-bees +(Cf. "The Mason-bees": chapter 7.--Translator's Note.), the +caterpillar of the Great Peacock Moth (Cf. "Social Life in the Insect +World" by J.H. Fabre, translated by Bernard Miall: chapter 14.-- +Translator's Note.) and many others, when subjected to similar tests, +are guilty of the same illogical behaviour: they continue, in the +normal order, their series of industrious actions, though an accident +has now rendered them all useless. Just like millstones unable to +cease revolving though there be no corn left to grind, let them once +be given the compelling power and they will continue to perform their +task despite its futility. Are they then machines? Far be it from me +to think anything so foolish. + +It is impossible to make definite progress on the shifting sands of +contradictory facts: each step in our interpretation may find us +embogged. And yet these facts speak so loudly that I do not hesitate +to translate their evidence as I understand it. In insect mentality, +we have to distinguish two very different domains. One of these is +INSTINCT properly so called, the unconscious impulse that presides +over the most wonderful part of what the creature achieves. Where +experience and imitation are of absolutely no avail, instinct lays +down its inflexible law. It is instinct and instinct alone that makes +the mother build for a family which she will never see; that counsels +the storing of provisions for the unknown offspring; that directs the +sting towards the nerve-centres of the prey and skilfully paralyses +it, so that the game may keep good; that instigates, in fine, a host +of actions wherein shrewd reason and consummate science would have +their part, were the creature acting through discernment. + +This faculty is perfect of its kind from the outset, otherwise the +insect would have no posterity. Time adds nothing to it and takes +nothing from it. Such as it was for a definite species, such it is +to-day and such it will remain, perhaps the most settled zoological +characteristic of them all. It is not free nor conscious in its +practice, any more than is the faculty of the stomach for digestion +or that of the heart for pulsation. The phases of its operations are +predetermined, necessarily entailed one by another; they suggest a +system of clock-work wherein one wheel set in motion brings about the +movement of the next. This is the mechanical side of the insect, the +fatum, the only thing which is able to explain the monstrous +illogicality of a Pelopaeus when misled by my artifices. Is the Lamb +when it first grips the teat a free and conscious agent, capable of +improvement in its difficult art of taking nourishment? The insect is +no more capable of improvement in its art, more difficult still, of +giving nourishment. + +But, with its hide-bound science ignorant of itself, pure insect, if +it stood alone, would leave the insect unarmed in the perpetual +conflict of circumstances. No two moments in time are identical; +though the background remain the same, the details change; the +unexpected rises on every side. In this bewildering confusion, a +guide is needed to seek, accept, refuse and select; to show +preference for this and indifference to that; to turn to account, in +short, anything useful that occasion may offer. This guide the insect +undoubtedly possesses, to a very manifest degree. It is the second +province of its mentality. Here it is conscious and capable of +improvement by experience. I dare not speak of this rudimentary +faculty as intelligence, which is too exalted a title: I will call it +DISCERNMENT. The insect, in exercising its highest gifts, discerns, +differentiates between one thing and another, within the sphere of +its business, of course; and that is about all. + +As long as we confound acts of pure instinct and acts of discernment +under the same head, we shall fall back into those endless +discussions which embitter controversy without bringing us one step +nearer to the solution of the problem. Is the insect conscious of +what it does? Yes and no. No, if its action is in the province of +instinct; yes, if the action is in that of discernment. Are the +habits of an insect capable of modification? No, decidedly not, if +the habit in question belongs to the province of instinct; yes, if it +belongs to that of discernment. Let us state this fundamental +distinction more precisely by the aid of a few examples. + +The Pelopaeus builds her cells with earth already softened, with mud. +Here we have instinct, the unalterable characteristic of the worker. +She has always built in this way and always will. The passing ages +will never teach her, neither the struggle for life nor the law of +selection will ever induce her to imitate the Mason-bee and collect +dry dust for her mortar. This mud nest needs a shelter against the +rain. The hiding-place under a stone suffices at first. But should +she find something better, the potter takes possession of that +something better and instals herself in the home of man. (The +Pelopaeus builds in the fire-places of houses.--Translator's Note.) +There we have discernment, the source of some sort of capacity for +improvement. + +The Pelopaeus supplies her larvae with provisions in the form of +Spiders. There you have instinct. The climate, the longitude or +latitude, the changing seasons, the abundance or scarcity of game +introduce no modification into this diet, though the larva shows +itself satisfied with other fare provided by myself. Its forebears +were brought up on Spiders; their descendants consumed similar food; +and their posterity again will know no other. Not a single +circumstance, however favourable, will ever persuade the Pelopaeus +that young Crickets, for instance, are as good as Spiders and that +her family would accept them gladly. Instinct binds her down to the +national diet. + +But, should the Epeira (The Weaving or Garden Spider. Cf. "The Life +of the Spider" by J. Henri Fabre translated by Alexander Teixeira de +Mattos; chapters 9 to 14 and appendix.--Translator's Note.), the +favourite prey, be lacking, must the Pelopaeus therefore give up +foraging? She will stock her warehouses all the same, because any +Spider suits her. There you have discernment, whose elasticity makes +up, in certain circumstances, for the too-great rigidity of instinct. +Amid the innumerable variety of game, the huntress is able to discern +between what is Spider and what is not; and, in this way, she is +always prepared to supply her family, without quitting the domain of +her instinct. + +The Hairy Ammophila gives her larva a single caterpillar, a large +one, paralysed by as many pricks of her sting as it has nervous +centres in its thorax and abdomen. Her surgical skill in subduing the +monster is instinct displayed in a form which makes short work of any +inclination to see in it an acquired habit. In an art that can leave +no one to practise it in the future unless that one be perfect at the +outset, of what avail are happy chances, atavistic tendencies, the +mellowing hand of time? But the grey caterpillar, sacrificed one day, +may be succeeded on another day by a green, yellow or striped +caterpillar. There you have discernment, which is quite capable of +recognizing the regulation prey under very diverse garbs. + +The Megachiles build their honey-jars with disks cut out of leaves; +certain Anthidia make felted cotton wallets; others fashion pots out +of resin. There you have instinct. Will any rash mind ever conceive +the singular idea that the Leaf-cutter might very well have started +working in cotton, that the cotton-wool-worker once thought or will +one day think of cutting disks out of the leaves of the lilac- and +the rose-tree, that the resin-kneader began with clay? Who would dare +to indulge in any such theories? Each Bee has her art, her medium, to +which she strictly confines herself. The first has her leaves; the +second her wadding; the third her resin. None of these guilds has +ever changed trades with another; and none ever will. There you have +instinct, keeping the workers to their specialities. There are no +innovations in their workshops, no recipes resulting from experiment, +no ingenious devices, no progress from indifferent to good, from good +to excellent. To-day's method is the facsimile of yesterday's; and +to-morrow will know no other. + +But, though the manufacturing-process is invariable, the raw material +is subject to change. The plant that supplies the cotton differs in +species according to the locality; the bush out of whose leaves the +pieces will be cut is not the same in the various fields of +operation; the tree that provides the resinous putty may be a pine, a +cypress, a juniper, a cedar or a spruce, all very different in +appearance. What will guide the insect in its gleaning? Discernment. + +These, I think, are sufficient details of the fundamental distinction +to be drawn in the insect's mentality; the distinction, that is, +between instinct and discernment. If people confuse these two +provinces, as they nearly always do, any understanding becomes +impossible; the last glimmer of light disappears behind the clouds of +interminable discussions. From an industrial point of view, let us +look upon the insect as a worker thoroughly versed from birth in a +craft whose essential principles never vary; let us grant that +unconscious worker a gleam of intelligence which will permit it to +extricate itself from the inevitable conflict of attendant +circumstances; and I think that we shall have come as near to the +truth as the state of our knowledge will allow for the moment. + +Having thus assigned a due share both to instinct and the aberrations +of instinct when the course of its different phases is disturbed, let +us see what discernment is able to do in the selection of a site for +the nest and materials for building it; and, leaving the Pelopaeus, +upon whom it is useless to dwell any longer, let us consider other +examples, picked from among those richest in variations. + +The Mason-bee of the Sheds (Chalicodoma rufitarsis, PEREZ) well +deserves the name which I have felt justified in giving her from her +habits: she settles in numerous colonies in our sheds, on the lower +surface of the tiles, where she builds huge nests which endanger the +solidity of the roof. Nowhere does the insect display a greater zeal +for work than in one of these colossal cities, an estate which is +constantly increasing as it passes down from one generation to +another; nowhere does it find a better workshop for the exercise of +its industry. Here it has plenty of room: a quiet resting-place, +sheltered from damp and from excess of heat or cold. + +But the spacious domain under the tiles is not within the reach of +all: sheds with free access and the proper sunny aspect are pretty +rare. These sites fall only to the favoured of fortune. Where will +the others take up their quarters? More or less everywhere. Without +leaving the house in which I live, I can enumerate stone, wood, +glass, metal, paint and mortar as forming the foundation of the +nests. The green-house with its furnace heat in the summer and its +bright light, equalling that outside, is fairly well-frequented. The +Mason-bee hardly ever fails to build there each year, in squads of a +few dozen apiece, now on the glass panes, now on the iron bars of the +framework. Other little swarms settle in the window embrasures, under +the projecting ledge of the front door or in the cranny between the +wall and an open shutter. Others again, being perhaps of a morose +disposition, flee society and prefer to work in solitude, one in the +inside of a lock or of a pipe intended to carry the rain-water from +the leads; another in the mouldings of the doors and windows or in +the crude ornamentation of the stone-work. In short, the house is +made use of all round, provided that the shelter be an out-of-door +one; for observe that the enterprising invader, unlike the Pelopaeus, +never penetrates inside our dwellings. The case of the conservatory +is an exception more apparent than real: the glass building, standing +wide open throughout the summer, is to the Mason-bee but a shed a +little lighter than the others. There is nothing here to arouse the +distrust with which anything indoors or shut up inspires her. To +build on the threshold of an outer door, or to usurp its lock, a +hiding-place to her fancy, is all that she allows herself; to go any +farther is an adventure repugnant to her taste. + +Lastly, in the case of all these dwellings, the Mason-bee is man's +free tenant; her industry makes use of the products of our own +industry. Can she have no other establishments? She has, beyond a +doubt; she possesses some constructed on the ancient plan. On a stone +the size of a man's fist, protected by the shelter of a hedge, +sometimes even on a pebble in the open air, I see her building now +groups of cells as large as a walnut, now domes emulating in size, +shape and solidity those of her rival, the Mason-bee of the Walls. + +The stone support is the most frequent, though not the only one. I +have found nests, but sparsely inhabited it is true, on the trunks of +trees, in the seams of the rough bark of oaks. Among those whose +support was a living plant, I will mention two that stand out above +all the others. The first was built in the lobe of a torch-thistle as +thick as my leg; the second rested on a stalk of the opuntia, the +Indian fig. Had the fierce armour of these two stout cactuses +attracted the attention of the insect, which looked upon their tufts +of spikes as furnishing a system of defence for its nest? Perhaps so. +In any case, the attempt was not imitated; I never saw another +installation of the kind. There is one definite conclusion to be +drawn from my two discoveries. Despite the oddity of their structure, +which is unparalleled among the local flora, the two American +importations did not compel the insect to go through an +apprenticeship of groping and hesitation. The one which found itself +in the presence of those novel growths, and which was perhaps the +first of its race to do so, took possession of their lobes and stalks +just as it would have done of a familiar site. From the start, the +fleshy plants from the New World suited it as well as the trunk of a +native tree. + +The Mason-bee of the Pebbles (Chalicodoma parietina) has none of this +elasticity in the choice of a site. In her case, the smooth stone of +the parched uplands is the almost invariable foundation of her +structures. Elsewhere, under a less clement sky, she prefers the +support of a wall, which protects the nest against the prolonged +snows. Lastly, the Mason-bee of the Shrubs (Chalicodoma rufescens, +PEREZ) fixes her ball of clay to a twig of any ligneous plant, from +the thyme, the rock-rose and the heath to the oak, the elm and the +pine. The list of the sites that suit her would almost form a +complete catalogue of the ligneous flora. + +The variety of places wherein the insect instals itself, so eloquent +of the part played by discernment in their selection, becomes still +more remarkable when it is accompanied by a corresponding variety in +the architecture of the cells. This is more particularly the case +with the Three-horned Osmia, who, as she uses clayey materials very +easily affected by the rain, requires, like the Pelopaeus, a dry +shelter for her cells, a shelter which she finds ready-made and uses +just as it is, after a few touches by way of sweeping and cleansing. +The homes which I see her adopt are especially the shells of Snails +that have died under the stone-heaps and in the low, unmortared walls +which support the cultivated earth of the hills in shelves or +terraces. The use of Snail-shells is accompanied by the no less +active use of the old cells of both the Mason-bee of the Sheds and of +certain Anthophorae (A. pilipes, A. parietina and A. personata). + +We must not forget the reed, which is highly appreciated when--a rare +find--it appears under the requisite conditions. In its natural +state, the plant with the mighty hollow cylinders is of no possible +use to the Osmia, who knows nothing of the art of perforating a woody +wall. The gallery of an internode has to be wide open before the +insect can take possession of it. Also, the clean-cut stump must be +horizontal, otherwise the rain would soften the fragile edifice of +clay and soon lay it low; also, the stump must not be lying on the +ground and must be kept at some distance from the dampness of the +soil. We see therefore that, without the intervention of man, +involuntary in the vast majority of cases and deliberate only on the +experimenter's part, the Osmia would hardly ever find a reed-stump +suited to the installation of her family. It is to her a casual +acquisition, a home unknown to her race before men took it into their +heads to cut reeds and make them into hurdles for drying figs in the +sun. + +How did the work of man's pruning-knife bring about the abandonment +of the natural lodging? How was the spiral staircase of the Snail- +shell replaced by the cylindrical gallery of the reed? Was the change +from one kind of house to another effected by gradual transitions, by +attempts made, abandoned, resumed, becoming more and more definite in +their results as generation succeeded generation? Or did the Osmia, +finding the cut reed that answered her requirements, instal herself +there straightway, scorning her ancient dwelling, the Snail-shell? +These questions called for a reply; and they have received one. Let +us describe how things happened. + +Near Serignan are some great quarries of coarse limestone, +characteristic of the miocene formation of the Rhone valley. These +have been worked for many generations. The ancient public buildings +of Orange, notably the colossal frontage of the theatre whither all +the intellectual world once flocked to hear Sophocles' "Oedipus +Tyrannus," derive most of their material from these quarries. Other +evidence confirms what the similarity of the hewn stone tells us. +Among the rubbish that fills up the spaces between the tiers of +seats, they occasionally discover the Marseilles obol, a bit of +silver stamped with the four-spoked wheel, or a few bronze coins +bearing the effigy of Augustus or Tiberius. Scattered also here and +there among the monuments of antiquity are heaps of refuse, +accumulations of broken stones in which various Hymenoptera, +including the Three-horned Osmia in particular, take possession of +the dead Snail-shell. + +The quarries form part of an extensive plateau which is so arid as to +be nearly deserted. In these conditions, the Osmia, at all times +faithful to her birth-place, has little or no need to emigrate from +her heap of stones and leave the shell for another dwelling which she +would have to go and seek at a distance. Since there are heaps of +stone there, she probably has no other dwelling than the Snail-shell. +Nothing tells us that the present-day generations are not descended +in the direct line from the generations contemporary with the +quarryman who lost his as or his obol at this spot. All the +circumstances seem to point to it: the Osmia of the quarries is an +inveterate user of Snail-shells; so far as heredity is concerned, she +knows nothing whatever of reeds. Well, we must place her in the +presence of these new lodgings. + +I collect during the winter about two dozen well-stocked Snail-shells +and instal them in a quiet corner of my study, as I did at the time +of my enquiries into the distribution of the sexes. The little hive +with its front pierced with forty holes has bits of reed fitted to +it. At the foot of the five rows of cylinders I place the inhabited +shells and with these I mix a few small stones, the better to imitate +the natural conditions. I add an assortment of empty Snail-shells, +after carefully cleaning the interior so as to make the Osmia's stay +more pleasant. When the time comes for nest-building, the stay-at- +home insect will have, close beside the house of its birth, a choice +of two habitations: the cylinder, a novelty unknown to its race; and +the spiral staircase, the ancient ancestral home. + +The nests were finished at the end of May and the Osmiae began to +answer my list of questions. Some, the great majority, settled +exclusively in the reeds; the others remained faithful to the Snail- +shell or else entrusted their eggs partly to the spirals and partly +to the cylinders. With the first, who were the pioneers of +cylindrical architecture, there was no hesitation that I could +perceive: after exploring the stump of reed for a time and +recognizing it as serviceable, the insect instals itself there and, +an expert from the first touch, without apprenticeship, without +groping, without any tendencies bequeathed by the long practice of +its predecessors, builds its straight row of cells on a very +different plan from that demanded by the spiral cavity of the shell +which increases in size as it goes on. + +The slow school of the ages, the gradual acquisitions of the past, +the legacies of heredity count for nothing therefore in the Osmia's +education. Without any novitiate on its own part or that of its +forebears, the insect is versed straight away in the calling which it +has to pursue; it possesses, inseparable from its nature, the +qualities demanded by its craft: some which are invariable and belong +to the domain of instinct; others, flexible, belonging to the +province of discernment. To divide a free lodging into chambers by +means of mud partitions; to fill those chambers with a heap of +pollen-flour, with a few sups of honey in the central part where the +egg is to lie; in short, to prepare board and lodging for the +unknown, for a family which the mothers have never seen in the past +and will never see in the future: this, in its essential features, is +the function of the Osmia's instinct. Here, everything is +harmoniously, inflexibly, permanently preordained; the insect has but +to follow its blind impulse to attain the goal. But the free lodging +offered by chance varies exceedingly in hygienic conditions, in shape +and in capacity. Instinct, which does not choose, which does not +contrive, would, if it were alone, leave the insect's existence in +peril. To help her out of her predicament, in these complex +circumstances, the Osmia possesses her little stock of discernment, +which distinguishes between the dry and the wet, the solid and the +fragile, the sheltered and the exposed; which recognizes the worth or +the worthlessness of a site and knows how to sprinkle it with cells +according to the size and shape of the space at disposal. Here, +slight industrial variations are necessary and inevitable; and the +insect excels in them without any apprenticeship, as the experiment +with the native Osmia of the quarries has just proved. + +Animal resources have a certain elasticity, within narrow limits. +What we learn from the animals' industry at a given moment is not +always the full measure of their skill. They possess latent powers +held in reserve for certain emergencies. Long generations can succeed +one another without employing them; but, should some circumstance +require it, suddenly those powers burst forth, free of any previous +attempts, even as the spark potentially contained in the flint +flashes forth independently of all preceding gleams. Could one who +knew nothing of the Sparrow but her nest under the eaves suspect the +ball-shaped nest at the top of a tree? Would one who knew nothing of +the Osmia save her home in the Snail-shell expect to see her accept +as her dwelling a stump of reed, a paper funnel, a glass tube? My +neighbour the Sparrow, impulsively taking it into her head to leave +the roof for the plane-tree, the Osmia of the quarries, rejecting her +natal cabin, the spiral of the shell, for my cylinder, alike show us +how sudden and spontaneous are the industrial variations of animals. + + +CHAPTER 7. ECONOMY OF ENERGY. + +What stimulus does the insect obey when it employs the reserve powers +that slumber in its race? Of what use are its industrial variations? +The Osmia will yield us her secret with no great difficulty. Let us +examine her work in a cylindrical habitation. I have described in +full detail, in the foregoing pages, the structure of her nests when +the dwelling adopted is a reed-stump or any other cylinder; and I +will content myself here with recapitulating the essential features +of that nest-building. + +We must first distinguish three classes of reeds according to their +diameter: the small, the medium-sized and the large. I call small +those whose narrow width just allows the Osmia to go about her +household duties without discomfort. She must be able to turn where +she stands in order to brush her abdomen and rub off its load of +pollen, after disgorging the honey in the centre of the heap of flour +already collected. If the width of the tube does not admit of this +operation, if the insect is obliged to go out and then come in again +backwards in order to place itself in a favourable posture for the +discharge of the pollen, then the reed is too narrow and the Osmia is +rather reluctant to accept it. The middle-sized reeds and a fortiori +the large ones leave the victualler entire liberty of action; but the +former do not exceed the width of a cell, a width agreeing with the +bulk of the future cocoon, whereas the latter, with their excessive +diameter, require more than one chamber on the same floor. + +When free to choose, the Osmia settles by preference in the small +reeds. Here, the work of building is reduced to its simplest +expression and consists in dividing the tube by means of earthen +partitions into a straight row of cells. Against the partition +forming the back wall of the preceding cell the mother places first a +heap of honey and pollen; next, when the portion is seen to be +enough, she lays an egg in the centre of it. Then and then only she +resumes her plasterer's work and marks out the length of the new cell +with a mud partition. This partition in its turn serves as the rear- +wall of another chamber, which is first victualled and then closed; +and so on until the cylinder is sufficiently colonized and receives a +thick terminal stopper at its orifice. In a word, the chief +characteristic of this method of nest-building, the roughest of all, +is that the partition in front is not undertaken so long as the +victualling is still incomplete, or, in other words, that the +provisions and the egg are deposited before the Bee sets to work on +the partition. + +At first sight, this latter detail hardly deserves attention: is it +not right to fill the pot before we put a lid on? The Osmia who owns +a medium-sized reed is not at all of this opinion; and other +plasterers share her views, as we shall see when we watch the +Odynerus building her nest. (A genus of Mason-wasps, the essays on +which have not yet been translated into English.--Translator's Note.) +Here we have an excellent illustration of one of those latent powers +held in reserve for exceptional occasions and suddenly brought into +play, although often very far removed from the insect's regular +methods. If the reed, without being of inordinate width from the +point of view of the cocoon, is nevertheless too spacious to afford +the Bee a suitable purchase against the wall at the moment when she +is disgorging honey and brushing off her load of pollen; the Osmia +altogether changes the order of her work; she sets up the partition +first and then does the victualling. + +All round the inside of the tube she places a ring of mud, which, as +the result of her constant visits to the mortar, ends by becoming a +complete diaphragm minus an orifice at the side, a sort of round dog- +hole, just large enough for the insect to pass through. When the cell +is thus marked out and almost wholly closed, the Osmia attends to the +storing of her provisions and the laying of her eggs. Steadying +herself against the margin of the hole at one time with her fore-legs +and at another with her hind-legs, she is able to empty her crop and +to brush her abdomen; by pressing against it, she obtains a foothold +for her little efforts in these various operations. When the tube was +narrow, the outer wall supplied this foothold and the earthen +partition was postponed until the heap of provisions was completed +and surmounted by the egg; but in the present case the passage is too +wide and would leave the insect floundering helplessly in space, so +the partition with its serving-hatch takes precedence of the +victuals. This method is a little more expensive than the other, +first in materials, because of the diameter of the reed, and secondly +in time, if only because of the dog-hole, a delicate piece of mortar- +work which is too soft at first and cannot be used until it has dried +and become harder. Therefore the Osmia, who is sparing of her time +and strength, accepts medium-sized reeds only when there are no small +ones available. + +The large tubes she will use only in grave emergencies and I am +unable to state exactly what these exceptional circumstances are. +Perhaps she decides to make use of those roomy dwellings when the +eggs have to be laid at once and there is no other shelter in the +neighbourhood. While my cylinder-hives gave me plenty of well-filled +reeds of the first and second class, they provided me with but half- +a-dozen at most of the third, notwithstanding my precaution to +furnish the apparatus with a varied assortment. + +The Osmia's repugnance to big cylinders is quite justified. The work +in fact is longer and more costly when the tubes are wide. An +inspection of a nest constructed under these conditions is enough to +convince us. It now consists not of a string of chambers obtained by +simple transverse partitions, but of a confused heap of clumsy, many- +sided compartments, standing back to back, with a tendency to group +themselves in storeys without succeeding in doing so, because any +regular arrangement would mean that the ceilings possessed a span +which it is not in the builder's power to achieve. The edifice is not +a geometrical masterpiece and it is even less satisfactory from the +point of view of economy. In the previous constructions, the sides of +the reed supplied the greater part of the walls and the work was +limited to one partition for each cell. Here, except at the actual +periphery, where the tube itself supplies a foundation, everything +has to be obtained by sheer building: the floor, the ceiling, the +walls of the many-sided compartment are one and all made of mortar. +The structure is almost as costly in materials as that of the +Chalicodoma or the Pelopaeus. + +It must be pretty difficult, too, when one thinks of its +irregularity. Fitting as best she can the projecting angles of the +new cell into the recessed corners of the cell already built, the +Osmia runs up walls more or less curved, upright or slanting, which +intersect one another at various points, so that each compartment +requires a new and complicated plan of construction, which is very +different from the circular-partition style of architecture, with its +row of parallel dividing-disks. Moreover, in this composite +arrangement, the size of the recesses left available by the earlier +work to some extent decides the assessment of the sexes, for, +according to the dimensions of those recesses, the walls erected take +in now a larger space, the home of a female, and now a smaller space, +the home of a male. Roomy quarters therefore have a double drawback +for the Osmia: they greatly increase the outlay in materials; and +also they establish in the lower layers, among the females, males +who, because of their earlier hatching, would be much better placed +near the mouth of the nest. I am convinced of it: if the Osmia +refuses big reeds and accepts them only in the last resort, when +there are no others, it is because she objects to additional labour +and to the mixture of the sexes. + +The Snail-shell, then, is but an indifferent home for her, which she +is quite ready to abandon should a better offer. Its expanding cavity +represents an average between the favourite small cylinder and the +unpopular large cylinder, which is accepted only when there is no +other obtainable. The first whorls of the spiral are too narrow to be +of use to the Osmia, but the middle ones have the right diameter for +cocoons arranged in single file. Here things happen as in a first- +class reed, for the helical curve in no way affects the method of +structure employed for a rectilinear series of cells. Circular +partitions are erected at the required distances, with or without a +serving-hatch, according to the diameter. These mark out the first +cells, one after the other, which are reserved solely for the +females. Then comes the last whorl, which is much too wide for a +single row of cells; and here we once more find, exactly as in a wide +reed, a costly profusion of masonry, an irregular arrangement of the +cells and a mixture of the sexes. + +Having said so much, let us go back to the Osmia of the quarries. +Why, when I offer them simultaneously Snail-shells and reeds of a +suitable size, do the old frequenters of the shells prefer the reeds, +which in all probability have never before been utilized by their +race? Most of them scorn the ancestral dwelling and enthusiastically +accept my reeds. Some, it is true, take up their quarters in the +Snail-shell; but even among these a goodly number refuse my new +shells and return to their birth-place, the old Snail-shell, in order +to utilize the family property, without much labour, at the cost of a +few repairs. Whence, I ask, comes this general preference for the +cylinder, never used hitherto? The answer can be only this: of two +lodgings at her disposal the Osmia selects the one that provides a +comfortable home at a minimum outlay. She economizes her strength +when restoring an old nest; she economizes it when replacing the +Snail-shell by the reed. + +Can animal industry, like our own, obey the law of economy, the +sovran law that governs our industrial machine even as it governs, at +least to all appearances, the sublime machine of the universe? Let us +go deeper into the question and bring other workers into evidence, +those especially who, better equipped perhaps and at any rate better +fitted for hard work, attack the difficulties of their trade boldly +and look down upon alien establishments with scorn. Of this number +are the Chalicodomae, the Mason-bees proper. + +The Mason-bee of the Pebbles does not make up her mind to build a +brand-new dome unless there be a dearth of old and not quite +dilapidated nests. The mothers, sisters apparently and heirs-at-law +to the domain, dispute fiercely for the ancestral abode. The first +who, by sheer brute force, takes possession of the dome, perches upon +it and, for long hours, watches events while polishing her wings. If +some claimant puts in an appearance, forthwith the other turns her +out with a volley of blows. In this way the old nests are employed so +long as they have not become uninhabitable hovels. + +Without being equally jealous of the maternal inheritance, the Mason- +bee of the Sheds eagerly uses the cells whence her generation issued. +The work in the huge city under the eaves begins thus: the old cells, +of which, by the way, the good-natured owner yields a portion to +Latreille's Osmia and to the Three-horned Osmia alike, are first made +clean and wholesome and cleared of broken plaster and then +provisioned and shut. When all the accessible chambers are occupied, +the actual building begins with a new stratum of cells upon the +former edifice, which becomes more and more massive from year to +year. + +The Mason-bee of the Shrubs, with her spherical nests hardly larger +than walnuts, puzzled me at first. Does she use the old buildings or +does she abandon them for good? To-day perplexity makes way for +certainty: she uses them very readily. I have several times surprised +her lodging her family in the empty rooms of a nest where she was +doubtless born herself. Like her kinswoman of the Pebbles, she +returns to the native dwelling and fights for its possession. Also, +like the dome-builder, she is an anchorite and prefers to cultivate +the lean inheritance alone. Sometimes, however, the nest is of +exceptional size and harbours a crowd of occupants, who live in +peace, each attending to her business, as in the colossal hives in +the sheds. Should the colony be at all numerous and the estate +descend to two or three generations in succession, with a fresh layer +of masonry each year, the normal walnut-sized nest becomes a ball as +large as a man's two fists. I have gathered on a pine-tree a nest of +the Mason-bee of the Shrubs that weighed a kilogram (2.205 pounds +avoirdupois.--Translator's Note.) and was the size of a child's head. +A twig hardly thicker than a straw served as its support. The casual +sight of that lump swinging over the spot on which I had sat down +made me think of the mishap that befell Garo. (The hero of La +Fontaine's fable, "Le Gland et la Citrouille," who wondered why +acorns grew on such tall trees and pumpkins on such low vines, until +he fell asleep under one of the latter and a pumpkin dropped upon his +nose.--Translator's Note.) If such nests were plentiful in the trees, +any one seeking the shade would run a serious risk of having his head +smashed. + +After the Masons, the Carpenters. Among the guild of wood-workers, +the most powerful is the Carpenter-bee (Xylocopa violacea (Cf. "The +Life of the Spider": chapter 1.--Translator's Note.)), a very large +Bee of formidable appearance, clad in black velvet with violet- +coloured wings. The mother gives her larvae as a dwelling a +cylindrical gallery which she digs in rotten wood. Useless timber +lying exposed to the air, vine-poles, large logs of fire-wood +seasoning out of doors, heaped up in front of the farmhouse porch, +stumps of trees, vine-stocks and big branches of all kinds are her +favourite building-yards. A solitary and industrious worker, she +bores, bit by bit, circular passages the width of one's thumb, as +clear-cut as though they were made with an auger. A heap of saw-dust +accumulates on the ground and bears witness to the severity of the +task. Usually, the same aperture is the entrance to two or three +parallel corridors. With several galleries there is accommodation for +the entire laying, though each gallery is quite short; and the Bee +thus avoids those long series which always create difficulties when +the moment of hatching arrives. The laggards and the insects eager to +emerge are less likely to get in each other's way. + +After obtaining the dwelling, the Carpenter-bee behaves like the +Osmia who is in possession of a reed. Provisions are collected, the +egg is laid and the chamber is walled in front with a saw-dust +partition. The work is pursued in this way until the two or three +passages composing the house are completely stocked. Heaping up +provisions and erecting partitions are an invariable feature of the +Xylocopa's programme; no circumstance can release the mother from the +duty of providing for the future of her family, in the matter both of +ready-prepared food and of separate compartments for the rearing of +each larva. It is only in the boring of the galleries, the most +laborious part of the work, that economy can occasionally be +exercised by a piece of luck. Well, is the powerful Carpenter, all +unheeding of fatigue, able to take advantage of such fortunate +occasions? Does she know how to make use of houses which she has not +tunnelled herself? Why, yes: a free lodging suits her just as much as +it does the various Mason-bees. She knows as well as they the +economic advantages of an old nest that is still in good condition: +she settles down, as far as possible, in her predecessors' galleries, +after freshening up the sides with a superficial scraping. And she +does better still. She readily accepts lodgings which have never +known a drill, no matter whose. The stout reeds used in the trellis- +work that supports the vines are valuable discoveries, providing as +they do sumptuous galleries free of cost. No preliminary work or next +to none is required with these. Indeed, the insect does not even +trouble to make a side-opening, which would enable it to occupy the +cavity contained within two nodes; it prefers the opening at the end +cut by man's pruning-knife. If the next partition be too near to give +a chamber of sufficient length, the Xylocopa destroys it, which is +easy work, not to be compared with the labour of cutting an entrance +through the side. In this way, a spacious gallery, following on the +short vestibule made by the pruning-knife, is obtained with the least +possible expenditure of energy. + +Guided by what was happening on the trellises, I offered the black +Bee the hospitality of my reed-hives. From the very beginning, the +insect gladly welcomed my advances; each spring, I see it inspect my +rows of cylinders, pick out the best ones and instal itself there. +Its work, reduced to a minimum by my intervention, is limited to the +partitions, the materials for which are obtained by scraping the +inner sides of the reed. + +As first-rate joiners, next to the Carpenter-bees come the Lithurgi, +of whom my district possesses two species: L. cornutus, FAB., and L. +chrysurus, BOY. By what aberration of nomenclature was the name of +Lithurgus, a worker in stone, given to insects which work solely in +wood? I have caught the first, the stronger of the two, digging +galleries in a large block of oak that served as an arch for a +stable-door; I have always found the second, who is more widely +distributed, settling in dead wood--mulberry, cherry, almond, poplar- +-that was still standing. Her work is exactly the same as the +Xylocopa's, on a smaller scale. A single entrance-hole gives access +to three or four parallel galleries, assembled in a serried group; +and these galleries are subdivided into cells by means of saw-dust +partitions. Following the example of the big Carpenter-bee, Lithurgus +chrysurus knows how to avoid the laborious work of boring, when +occasion offers: I find her cocoons lodged almost as often in old +dormitories as in new ones. She too has the tendency to economize her +strength by turning the work of her predecessors to account. I do not +despair of seeing her adopt the reed if, one day, when I possess a +large enough colony, I decide to try this experiment on her. I will +say nothing about L. cornutus, whom I only once surprised at her +carpentering. + +The Anthophorae, those children of the precipitous earthy banks, show +the same thrifty spirit as the other members of the mining +corporation. Three species, A. parietina, A. personata and A. +pilipes, dig long corridors leading to the cells, which are scattered +here and there and one by one. These passages remain open at all +seasons of the year. When spring comes, the new colony uses them just +as they are, provided that they are well preserved in the clayey mass +baked by the sun; it increases their length if necessary, runs out a +few more branches, but does not decide to start boring in new ground +until the old city, which, with its many labyrinths, resembles some +monstrous sponge, is too much undermined for safety. The oval niches, +the cells that open on those corridors, are also profitably employed. +The Anthophora restores their entrance, which has been destroyed by +the insect's recent emergence; she smooths their walls with a fresh +coat of whitewash, after which the lodging is fit to receive the heap +of honey and the egg. When the old cells, insufficient in number and +moreover partly inhabited by diverse intruders, are all occupied, the +boring of new cells begins, in the extended sections of the +galleries, and the rest of the eggs are housed. In this way, the +swarm is settled at a minimum of expense. + +To conclude this brief account, let us change the zoological setting +and, as we have already spoken of the Sparrow, see what he can do as +a builder. The simplest form of his nest is the great round ball of +straw, dead leaves and feathers, in the fork of a few branches. It is +costly in material, but can be set up anywhere, when the hole in the +wall or the shelter of a tile are lacking. What reasons induced him +to give up the spherical edifice? To all seeming, the same reasons +that led the Osmia to abandon the Snail-shell's spiral, which +requires a fatiguing expenditure of clay, in favour of the economical +cylinder of the reed. By making his home in a hole in the wall, the +Sparrow escapes the greater part of his work. Here, the dome that +serves as a protection from the rain and the thick walls that offer +resistance to the wind both become superfluous. A mere mattress is +sufficient; the cavity in the wall provides the rest. The saving is +great; and the Sparrow appreciates it quite as much as the Osmia. + +This does not mean that the primitive art has disappeared, lost +through neglect; it remains an ineffaceable characteristic of the +species, ever ready to declare itself should circumstances demand it. +The generations of to-day are as much endowed with it as the +generations of yore; without apprenticeship, without the example of +others, they have within themselves, in the potential state, the +industrial aptitude of their ancestors. If aroused by the stimulus of +necessity, this aptitude will pass suddenly from inaction to action. +When, therefore, the Sparrow still from time to time indulges in +spherical building, this is not progress on his part, as is sometimes +contended; it is, on the contrary, a retrogression, a return to the +ancient customs, so prodigal of labour. He is behaving like the Osmia +who, in default of a reed, makes shift with a Snail-shell, which is +more difficult to utilize but easier to find. The cylinder and the +hole in the wall stand for progress; the spiral of the Snail-shell +and the ball-shaped nest represent the starting-point. + +I have, I think, sufficiently illustrated the inference which is +borne out by the whole mass of analogous facts. Animal industry +manifests a tendency to achieve the essential with a minimum of +expenditure; after its own fashion, the insect bears witness to the +economy of energy. On the one hand, instinct imposes upon it a craft +that is unchangeable in its fundamental features; on the other hand, +it is left a certain latitude in the details, so as to take advantage +of favourable circumstances and attain the object aimed at with the +least possible expenditure of time, materials and work, the three +elements of mechanical labour. The problem in higher geometry solved +by the Hive-bee is only a particular case--true, a magnificent case,- +-of this general law of economy which seems to govern the whole +animal world. The wax cells, with their maximum capacity as against a +minimum wall-space, are the equivalent, with the superaddition of a +marvellous scientific skill, of the Osmia's compartments in which the +stonework is reduced to a minimum through the selection of a reed. +The artificer in mud and the artificer in wax obey the same tendency: +they economize. Do they know what they are doing? Who would venture +to suggest it in the case of the Bee grappling with her +transcendental problem? The others, pursuing their rustic art, are no +wiser. With all of them, there is no calculation, no premeditation, +but simply blind obedience to the law of general harmony. + + +CHAPTER 8. THE LEAF-CUTTERS. + +It is not enough that animal industry should be able, to a certain +extent, to adapt itself to casual exigencies when choosing the site +of a nest; if the race is to thrive, something else is required, +something which hide-bound instinct is unable to provide. The +Chaffinch, for instance, introduces a great quantity of lichen into +the outer layer of his nest. This is his method of strengthening the +edifice and making a stout framework in which to place first the +bottom mattress of moss, fine straw and rootlets and then the soft +bed of feathers, wool and down. But, should the time-honoured lichen +be lacking, will the bird refrain from building its nest? Will it +forgo the delight of hatching its brood because it has not the +wherewithal to settle its family in the orthodox fashion? + +No, the chaffinch is not perplexed by so small a matter; he is an +expert in materials, he understands botanical equivalents. In the +absence of the branches of the evernias, he picks the long beards of +the usneas, the wartlike rosettes of the parmelias, the membranes of +the stictises torn away in shreds; if he can find nothing better, he +makes shift with the bushy tufts of the cladonias. As a practical +lichenologist, when one species is rare or lacking in the +neighbourhood, he is able to fall back on others, varying greatly in +shape, colour and texture. And, if the impossible happened and lichen +failed entirely, I credit the Chaffinch with sufficient talent to be +able to dispense with it and to build the foundations of his nest +with some coarse moss or other. + +What the worker in lichens tells us the other weavers of textile +materials confirm. Each has his favourite flora, which hardly ever +varies when the plant is easily accessible and which can be +supplemented by plenty of others when it is not. The bird's botany +would be worth examining; it would be interesting to draw up the +industrial herbal of each species. In this connection, I will quote +just one instance, so as not to stray too far from the subject in +hand. + +The Red-backed Shrike (Lanius collurio), the commonest variety in my +district, is noteworthy because of his savage mania for forked +gibbets, the thorns in the hedgerows whereon he impales the +voluminous contents of his game-bag--little half-fledged birds, small +Lizards, Grasshoppers, caterpillars, Beetles--and leaves them to get +high. To this passion for the gallows, which has passed unnoticed by +the country-folk, at least in my part, he adds another, an innocent +botanical passion, which is so much in evidence that everybody, down +to the youngest bird's-nester, knows all about it. His nest, a +massive structure, is made of hardly any other materials than a +greyish and very fluffy plant, which is found everywhere among the +corn. This is the Filago spathulata of the botanists; and the bird +also makes use, though less frequently, of the Filago germanica, or +common cotton-rose. Both are known in Provencal by the name herbo dou +tarnagas, or Shrike-herb. This popular designation tells us plainly +how faithful the bird is to its plant. To have struck the +agricultural labourer, a very indifferent observer, the Shrike's +choice of materials must be remarkably persistent. + +Have we here a taste that is exclusive? Not in the least. Though +cotton-roses of all species are plentiful on level ground, they +become scarce and impossible to find on the parched hills. The bird, +on its side, is not given to journeys of exploration and takes what +it finds to suit it in the neighbourhood of its tree or hedge. But on +arid ground, the Micropus erectus, or upright micropus, abounds and +is a satisfactory substitute for the Filago so far as its tiny, +cottony leaves and its little fluffy balls of flowers are concerned. +True, it is short and does not lend itself well to weaver's work. A +few long sprigs of another cottony plant, the Helichrysum staechas, +or wild everlasting, inserted here and there, will give body to the +structure. Thus does the Shrike manage when hard up for his favourite +materials: keeping to the same botanical family, he is able to find +and employ substitutes among the fine cotton-clad stalks. + +He is even able to leave the family of the Compositae and to go +gleaning more or less everywhere. Here is the result of my +botanizings at the expense of his nests. We must distinguish between +two genera in the Shrike's rough classification: the cottony plants +and the smooth plants. Among the first, my notes mention the +following: Convolvulus cantabrica, or flax-leaved bindweed; Lotus +symmetricus, or bird's-foot trefoil; Teucrium polium, or poly; and +the flowery heads of the Phragmites communis, or common reed. Among +the second are these: Medicago lupulina, or nonesuch; Trifolium +repens, or white clover; Lathyrus pratensis, or meadow lathyrus; +Capsella bursa pastoris, or shepherd's purse; Vicia peregrina, or +broad-podded vetch; Convolvulus arvensis, or small bindweed; +Pterotheca nemausensis, a sort of hawkweed; and Poa pratensis, or +smooth-stalked meadow-grass. When it is downy, the plant forms almost +the whole nest, as is the case with the flax-leaved bindweed; when +smooth, it forms only the framework, destined to support a crumbling +mass of micropus, as is the case with the small bindweed. When making +this collection, which I am far from giving as the birds' complete +herbarium, I was struck by a wholly unexpected detail: of the various +plants, I found only the heads still in bud; moreover, all the +sprigs, though dry, possessed the green colouring of the growing +plant, a sign of swift desiccation in the sun. Save in a few cases, +therefore, the Shrike does not collect the dead and withered remains: +it is from the growing plants that he reaps his harvest, mowing them +down with his beak and leaving the sheaves to dry in the sun before +using them. I caught him one day hopping about and pecking at the +twigs of a Biscayan bindweed. He was getting in his hay, strewing the +ground with it. + +The evidence of the Shrike, confirmed by that of all the other +workers--weavers, basket-makers or woodcutters--whom we may care to +call as witnesses, shows us what a large part must be assigned to +discernment in the bird's choice of materials for its nest. Is the +insect as highly gifted? When it works with vegetable matter, is it +exclusive in its tastes? Does it know only one definite plant, its +special province? Or has it, for employment in its manufactures, a +varied flora, in which its discernment exercises a free choice? For +answers to these questions we may look, above all, to the Leaf- +cutting Bees, the Megachiles. Reaumur has told the story of their +industry in detail; and I refer the reader who wishes for further +particulars to the master's Memoirs. + +The man who knows how to use his eyes in his garden will observe, +some day or other, a number of curious holes in the leaves of his +lilac- and rose-trees, some of them round, some oval, as if idle but +skilful hands had been at work with the pinking-iron. In some places, +there is scarcely anything but the veins of the leaves left. The +author of the mischief is a grey-clad Bee, a Megachile. For scissors, +she has her mandibles; for compasses, producing now an oval and anon +a circle, she has her eye and the pivot of her body. The pieces cut +out are made into thimble-shaped wallets, destined to contain the +honey and the egg: the larger, oval pieces supply the floor and +sides; the smaller, round pieces are reserved for the lid. A row of +these thimbles, placed one on top of the other, up to a dozen or +more, though often there are less: that is, roughly, the structure of +the Leaf-cutter's nest. + +When taken out of the recess in which the mother has manufactured it, +the cylinder of cells seems to be an indivisible whole, a sort of +tunnel obtained by lining with leaves some gallery dug underground. +The real thing does not correspond with its appearance: under the +least pressure of the fingers, the cylinder breaks up into equal +sections, which are so many compartments independent of their +neighbours as regards both floor and lid. This spontaneous break up +shows us how the work is done. The method agrees with those adopted +by the other Bees. Instead of a general scabbard of leaves, +afterwards subdivided into compartments by transverse partitions, the +Megachile constructs a string of separate wallets, each of which is +finished before the next is begun. + +A structure of this sort needs a sheath to keep the pieces in place +while giving them the proper shape. The bag of leaves, in fact, as +turned out by the worker, lacks stability; its numerous pieces, not +glued together, but simply placed one after the other, come apart and +give way as soon as they lose the support of the tunnel that keeps +them united. Later, when it spins its cocoon, the larva infuses a +little of its fluid silk into the gaps and solders the pieces to one +another, especially the inner ones, so much so that the insecure bag +in due course becomes a solid casket whose component parts it is no +longer possible to separate entirely. + +The protective sheath, which is also a framework, is not the work of +the mother. Like the great majority of the Osmiae, the Megachiles do +not understand the art of making themselves a home straight away: +they want a borrowed lodging, which may vary considerably in +character. The deserted galleries of the Anthophorae, the burrows of +the fat Earth-worms, the tunnels bored in the trunks of trees by the +larva of the Cerambyx-beetle (The Capricorn, the essay on which has +not yet been published in English.--Translator's Note.), the ruined +dwellings of the Mason-bee of the Pebbles, the Snail-shell nests of +the Three-horned Osmia, reed-stumps, when these are handy, and +crevices in the walls are all so many homes for the Leaf-cutters, who +choose this or that establishment according to the tastes of their +particular genus. + +For the sake of clearness, let us cease generalizing and direct our +attention to a definite species. I first selected the White-girdled +Leaf-cutter (Megachile albocincta, PEREZ), not on account of any +exceptional peculiarities, but solely because this is the Bee most +often mentioned in my notes. Her customary dwelling is the tunnel of +an Earth-worm opening on some clay bank. Whether perpendicular or +slanting, this tunnel runs down to an indefinite depth, where the +climate would be too damp for the Bee. Besides, when the time comes +for the hatching of the adult insect, its emergence would be fraught +with peril if it had to climb up from a deep pit through crumbling +rubbish. The Leaf-cutter, therefore, uses only the front portion of +the Worm's gallery, two decimetres at most. (7.8 inches.-- +Translator's Note.) What is to be done with the rest of the tunnel? +It is an ascending shaft, tempting to an enemy; and some underground +ravager might come this way and destroy the nest by attacking the row +of cells at the back. + +The danger is foreseen. Before fashioning her first honey-bag, the +Bee blocks the passage with a strong barricade composed of the only +materials used in the Leaf-cutter's guild. Fragments of leaves are +piled up in no particular order, but in sufficient quantities to make +a serious obstacle. It is not unusual to find in the leafy rampart +some dozens of pieces rolled into screws and fitting into one another +like a stack of cylindrical wafers. For this work of fortification, +artistic refinement seems superfluous; at any rate, the pieces of +leaves are for the most part irregular. You can see that the insect +has cut them out hurriedly, unmethodically and on a different pattern +from that of the pieces intended for the cells. + +I am struck with another detail in the barricade. Its constituents +are taken from stout, thick, strong-veined leaves. I recognize young +vine-leaves, pale-coloured and velvety; the leaves of the whitish +rock-rose (Cistus albidus), lined with a hairy felt; those of the +holm-oak, selected among the young and bristly ones; those of the +hawthorn, smooth but tough; those of the cultivated reed, the only +one of the Monocotyledones exploited, as far as I know, by the +Megachiles. In the construction of cells, on the other hand, I see +smooth leaves predominating, notably those of the wild briar and of +the common acacia, the robinia. It would appear, therefore, that the +insect distinguishes between two kinds of materials, without being an +absolute purist and sternly excluding any sort of blending. The very +much indented leaves, whose projections can be completely removed +with a dexterous snip of the scissors, generally furnish the various +layers of the barricade; the little robinia-leaves, with their fine +texture and their unbroken edges, are better suited to the more +delicate work of the cells. + +A rampart at the back of the Earth-worm's shaft is a wise precaution +and the Leaf-cutter deserves all credit for it; only it is a pity for +the Megachiles' reputation that this protective barrier often +protects nothing at all. Here we see, under a new guise, that +aberration of instinct of which I gave some examples in an earlier +chapter. My notes contain memoranda of various galleries crammed with +pieces of leaves right up to the orifice, which is on a level with +the ground, and entirely devoid of cells, even of an unfinished one. +These were ridiculous fortifications, of no use whatever; and yet the +Bee treated the matter with the utmost seriousness and took infinite +pains over her futile task. One of these uselessly barricaded +galleries furnished me with some hundred pieces of leaves arranged +like a stack of wafers; another gave me as many as a hundred and +fifty. For the defence of a tenanted nest, two dozen and even fewer +are ample. Then what was the object of the Leaf-cutter's ridiculous +pile? + +I wish I could believe that, seeing that the place was dangerous, she +made her heap bigger so that the rampart might be in proportion to +the danger. Then, perhaps, at the moment of starting on the cells, +she disappeared, the victim of an accident, blown out of her course +by a gust of wind. But this line of defence is not admissible in the +Megachile's case. The proof is palpable: the galleries aforesaid are +barricaded up to the level of the ground; there is no room, +absolutely none, to lodge even a single egg. What was her object, I +ask again, when she persisted in obstinately piling up her wafers? +Has she really an object? + +I do not hesitate to say no. And my answer is based upon what the +Osmiae taught me. I have described above how the Three-horned Osmia, +towards the end of her life, when her ovaries are depleted, expends +on useless operations such energy as remains to her. Born a worker, +she is bored by the inactivity of retirement; her leisure requires an +occupation. Having nothing better to do, she sets up partitions; she +divides a tunnel into cells that will remain empty; she closes with a +thick plug reeds containing nothing. Thus is the modicum of strength +of her decline exhausted in vain labours. The other Builder-bees +behave likewise. I see Anthidia laboriously provide numerous bales of +cotton to stop galleries wherein never an egg was laid; I see +Mason-bees build and then religiously close cells that will remain +unvictualled and uncolonized. + +The long and useless barricades then belong to the last hours of the +Megachile's life, when the eggs are all laid; the mother, whose +ovaries are exhausted, persists in building. Her instinct is to cut +out and heap up pieces of leaves; obeying this impulse, she cuts out +and heaps up even when the supreme reason for this labour ceases. The +eggs are no longer there, but some strength remains; and that +strength is expended as the safety of the species demanded in the +beginning. The wheels of action go on turning in the absence of the +motives for action; they continue their movement as though by a sort +of acquired velocity. What clearer proof can we hope to find of the +unconsciousness of the animal stimulated by instinct? + +Let us return to the Leaf-cutter's work under normal conditions. +Immediately after a protective barrier comes the row of cells, which +vary considerably in number, like those of the Osmia in her reed. +Strings of about a dozen are rare; the most frequent consist of five +or six. No less subject to variation is the number of pieces joined +to make a cell: pieces of two kinds, some, the oval ones, forming the +honey-pot; others, the round ones, serving as a lid. I count, on an +average, eight to ten pieces of the first kind. Though all cut on the +pattern of an ellipse, they are not equal in dimensions and come +under two categories. The larger, outside ones are each of them +almost a third of the circumference and overlap one another slightly. +Their lower end bends into a concave curve to form the bottom of the +bag. Those inside, which are considerably smaller, increase the +thickness of the sides and fill up the gaps left by the first. + +The Leaf-cutter therefore is able to use her scissors according to +the task before her: first, the large pieces, which help the work +forward, but leave empty spaces; next, the small pieces, which fit +into the defective portions. The bottom of the cell particularly +comes in for after-touches. As the natural curve of the larger pieces +is not enough to provide a cup without cracks in it, the Bee does not +fail to improve the work with two or three small oval pieces applied +to the imperfect joins. + +Another advantage results from the snippets of unequal size. The +three or four outer pieces, which are the first placed in position, +being the longest of all, project beyond the mouth, whereas the next, +being shorter, do not come quite up to it. A brim is thus obtained, a +ledge on which the round disks of the lid rest and are prevented from +touching the honey when the Bee presses them into a concave cover. In +other words, at the mouth the circumference comprises only one row of +leaves; lower down it takes two or three, thus restricting the +diameter and securing an hermetic closing. + +The cover of the pot consists solely of round pieces, very nearly +alike and more or less numerous. Sometimes I find only two, sometimes +I count as many as ten, closely stacked. At times, the diameter of +these pieces is of an almost mathematical precision, so much so that +the edges of the disk rest upon the ledge. No better result would be +obtained had they been cut out with the aid of compasses. At times, +again, the piece projects slightly beyond the mouth, so that, to +enter, it has to be pressed down and curved cupwise. There is no +variation in the diameter of the first pieces placed in position, +those nearest to the honey. They are all of the same size and thus +form a flat cover which does not encroach on the cell and will not +afterwards interfere with the larva, as a convex ceiling would. The +subsequent disks, when the pile is numerous, are a little larger; +they only fit the mouth by yielding to pressure and becoming concave. +The Bee seems to make a point of this concavity, for it serves as a +mould to receive the curved bottom of the next cell. + +When the row of cells is finished, the task still remains of blocking +up the entrance to the gallery with a safety-stopper similar to the +earthen plug with which the Osmia closes her reeds. The Bee then +returns to the free and easy use of the scissors which we noticed at +the beginning when she was fencing off the back part of the Earth- +worm's too deep burrow; she cuts out of the foliage irregular pieces +of different shapes and sizes and often retaining their original +deeply-indented margins; and with all these pieces, very few of which +fit at all closely the orifice to be blocked, she succeeds in making +an inviolable door, thanks to the huge number of layers. + +Let us leave the Leaf-cutter to finish depositing her eggs in other +galleries, which will be colonized in the same manner, and consider +for a moment her skill as a cutter. Her edifices consist of a +multitude of fragments belonging to three categories: oval pieces for +the sides of the cells; round pieces for the lids; and irregular +pieces for the barricades at the front and back. The last present no +difficulty: the Bee obtains them by removing from the leaf some +projecting portion, as it stands, a serrate lobe which, owing to its +notches, shortens the insect's task and lends itself better to +scissor-work. So far, there is nothing to deserve attention: it is +unskilled labour, in which an inexperienced apprentice might excel. + +With the oval pieces, it becomes another matter. What model has the +Megachile when cutting her neat ellipses out of the delicate material +for her wallets, the robinia-leaves? What mental pattern guides her +scissors? What system of measurement tells her the dimensions? One +would like to picture the insect as a living pair of compasses, +capable of tracing an elliptic curve by a certain natural inflexion +of its body, even as our arm traces a circle by swinging from the +shoulder. A blind mechanism, the mere outcome of its organization, +would alone be responsible for its geometry. This explanation would +tempt me if the large oval pieces were not accompanied by much +smaller ones, also oval, which are used to fill the empty spaces. A +pair of compasses which changes its radius of its own accord and +alters the curve according to the plan before it appears to me an +instrument somewhat difficult to believe in. There must be something +better than that. The circular pieces of the lid suggest it to us. + +If, by the mere flexion inherent in her structure, the Leaf-cutter +succeeds in cutting out ovals, how does she succeed in cutting out +rounds? Can we admit the presence of other wheels in the machinery +for the new pattern, so different in shape and size? Besides, the +real point of the difficulty does not lie there. These rounds, for +the most part, fit the mouth of the jar with almost exact precision. +When the cell is finished, the Bee flies hundreds of yards away to +make the lid. She arrives at the leaf from which the disk is to be +cut. What picture, what recollection has she of the pot to be +covered? Why, none at all: she has never seen it; she does her work +underground, in utter darkness! At the utmost, she can have the +indications of touch: not actual indications, of course, for the pot +is not there, but past indications, useless in a work of precision. +And yet the disk to be cut out must have a fixed diameter: if it were +too large, it would not go in; if too small, it would close badly, it +would slip down on the honey and suffocate the egg. How shall it be +given its correct dimensions without a pattern? The Bee does not +hesitate for a moment. She cuts out her disk with the same celerity +which she would display in detaching any shapeless lobe that might do +for a stopper; and that disk, without further measurement, is of the +right size to fit the pot. Let whoso will explain this geometry, +which in my opinion is inexplicable, even when we allow for memory +begotten of touch and sight. + +One winter evening, as we were sitting round the fire, whose cheerful +blaze unloosed our tongues, I put the problem of the Leaf-cutter to +my family: + +'Among your kitchen-utensils,' I said, 'you have a pot in daily use; +but it has lost its lid, which was knocked over and broken by the +Tomcat playing among the shelves. To-morrow is market-day and one of +you will be going to Orange to buy the week's provisions. Would she +undertake, without a measure of any kind, with the sole aid of +memory, which we would allow her to refresh before starting by a +careful examination of the object, to bring back exactly what the pot +wants, a lid neither too large nor too small, in short the same size +as the top?' + +It was admitted with one accord that nobody would accept such a +commission without taking a measure with her, or at least a bit of +string giving the width. Our memory for sizes is not accurate enough. +She would come back from the town with something that 'might do'; and +it would be the merest chance if this turned out to be the right +size. + +Well, the Leaf-cutter is even less well-off than ourselves. She has +no mental picture of her pot, because she has never seen it; she is +not able to pick and choose in the crockery-dealer's heap, which acts +as something of a guide to our memory by comparison; she must, +without hesitation, far away from her home, cut out a disk that fits +the top of her jar. What is impossible to us is child's-play to her. +Where we could not do without a measure of some kind, a bit of +string, a pattern or a scrap of paper with figures upon it, the +little Bee needs nothing at all. In housekeeping matters she is +cleverer than we are. + +One objection was raised. Was it not possible that the Bee, when at +work on the shrub, should first cut a round piece of an approximate +diameter, larger than that of the neck of the jar, and that +afterwards, on returning home, she should gnaw away the superfluous +part until the lid exactly fitted the pot? These alterations made +with the model in front of her would explain everything. + +That is perfectly true; but are there any alterations? To begin with, +it seems to me hardly possible that the insect can go back to the +cutting once the piece is detached from the leaf: it lacks the +necessary support to gnaw the flimsy disk with any precision. A +tailor would spoil his cloth if he had not the support of a table +when cutting out the pieces for a coat. The Megachile's scissors, so +difficult to wield on anything not firmly held, would do equally bad +work. + +Besides, I have better evidence than this for my refusal to believe +in the existence of alterations when the Bee has the cell in front of +her. The lid is composed of a pile of disks whose number sometimes +reaches half a score. Now the bottom part of all these disks is the +under surface of the leaf, which is paler and more strongly veined; +the top part is the upper surface, which is smooth and greener. In +other words, the insect places them in the position which they occupy +when gathered. Let me explain. In order to cut out a piece, the Bee +stands on the upper surface of the leaf. The piece detached is held +in the feet and is therefore laid with its top surface against the +insect's chest at the moment of departure. There is no possibility of +its being turned over on the journey. Consequently, the piece is laid +as the Bee has just picked it, with the lower surface towards the +inside of the cell and the upper surface towards the outside. If +alterations were necessary to reduce the lid to the diameter of the +pot, the disk would be bound to get turned over: the piece, +manipulated, set upright, turned round, tried this way and that, +would, when finally laid in position, have its top or bottom surface +inside just as it happened to come. But this is exactly what does not +take place. Therefore, as the order of stacking never changes, the +disks are cut, from the first clip of the scissors, with their proper +dimensions. The insect excels us in practical geometry. I look upon +the Leaf-cutter's pot and lid as an addition to the many other +marvels of instinct that cannot be explained by mechanics; I submit +it to the consideration of science; and I pass on. + +The Silky Leaf-cutter (Megachile sericans, FONSCOL.; M. Dufourii, +LEP.) makes her nests in the disused galleries of the Anthophorae. I +know her to occupy another dwelling which is more elegant and affords +a more roomy installation: I mean the old dwelling of the fat +Capricorn, the denizen of the oaks. The metamorphosis is effected in +a spacious chamber lined with soft felt. When the long-horned Beetle +reaches the adult stage, he releases himself and emerges from the +tree by following a vestibule which the larva's powerful tools have +prepared beforehand. When the deserted cabin, owing to its position, +remains wholesome and there is no sign of any running from its walls, +no brown stuff smelling of the tan-yard, it is soon visited by the +Silky Megachile, who finds in it the most sumptuous of the apartments +inhabited by the Leaf-cutters. It combines every condition of +comfort: perfect safety, an even temperature, freedom from damp, +ample room; and so the mother who is fortunate enough to become the +possessor of such a lodging uses it entirely, vestibule and drawing- +room alike. Accommodation is found for all her family of eggs; at +least, I have nowhere seen nests as populous as here. + +One of them provides me with seventeen cells, the highest number +appearing in my census of the Megachile clan. Most of them are lodged +in the nymphal chamber of the Capricorn; and, as the spacious recess +is too wide for a single row, the cells are arranged in three +parallel series. The remainder, in a single string, occupy the +vestibule, which is completed and filled up by the terminal +barricade. In the materials employed, hawthorn-and paliurus-leaves +predominate. The pieces, both in the cells and in the barrier, vary +in size. It is true that the hawthorn-leaves, with their deep +indentations, do not lend themselves to the cutting of neat oval +pieces. The insect seems to have detached each morsel without +troubling overmuch about the shape of the piece, so long as it was +big enough. Nor has it been very particular about arranging the +pieces according to the nature of the leaf: after a few bits of +paliurus come bits of vine and hawthorn; and these again are followed +by bits of bramble and paliurus. The Bee has collected her pieces +anyhow, taking a bit here and there, just as her fancy dictated. +Nevertheless, paliurus is the commonest, perhaps for economical +reasons. + +I notice, in fact, that the leaves of this shrub, instead of being +used piecemeal, are employed whole, when they do not exceed the +proper dimensions. Their oval form and their moderate size suit the +insect's requirements; and there is therefore no necessity to cut +them into pieces. The leaf-stalk is clipped with the scissors and, +without more ado, the Megachile retires the richer by a first-rate +bit of material. + +Split up into their component parts, two cells give me altogether +eighty-three pieces of leaves, whereof eighteen are smaller than the +others and of a round shape. The last-named come from the lids. If +they average forty-two each, the seventeen cells of the nest +represent seven hundred and fourteen pieces. These are not all: the +nest ends, in the Capricorn's vestibule, with a stout barricade in +which I count three hundred and fifty pieces. The total therefore +amounts to one thousand and sixty-four. All those journeys and all +that work with the scissors to furnish the deserted chamber of the +Cerambyx! If I did not know the Leaf-cutter's solitary and jealous +disposition, I should attribute the huge structure to the +collaboration of several mothers; but there is no question of +communism in this case. One dauntless creature and one alone, one +solitary, inveterate worker, has produced the whole of the prodigious +mass. If work is the best way to enjoy life, this one certainly has +not been bored during the few weeks of her existence. + +I gladly award her the most honourable of eulogies, that due to the +industrious; and I also compliment her on her talent for closing the +honey-pots. The pieces stacked into lids are round and have nothing +to suggest those of which the cells and the final barricade are made. +Excepting the first, those nearest the honey, they are perhaps cut a +little less neatly than the disks of the White-girdled Leaf-cutter; +no matter: they stop the jar perfectly, especially when there are +some ten of them one above the other. When cutting them, the Bee was +as sure of her scissors as a dressmaker guided by a pattern laid on +the stuff; and yet she was cutting without a model, without having in +front of her the mouth to be closed. To enlarge on this interesting +subject would mean to repeat oneself. All the Leaf-cutters have the +same talent for making the lids of their pots. + +A less mysterious question than this geometrical problem is that of +the materials. Does each species of Megachile keep to a single plant, +or has it a definite botanical domain wherein to exercise its liberty +of choice? The little that I have already said is enough to make us +suspect that the insect is not restricted to one plant; and this is +confirmed by an examination of the separate cells, piece by piece, +when we find a variety which we were far from imagining at first. +Here is the flora of the Megachiles in my neighbourhood, a very +incomplete flora and doubtless capable of considerable amplification +by future researches. + +The Silky Leaf-cutter gathers the materials for her pots, her lids +and her barricades from the following plants: paliurus, hawthorn, +vine, wild briar, bramble, holm-oak, amelanchier, terebinthus, sage- +leaved rock-rose. The first three supply the greater part of the +leaf-work; the last three are represented only by rare fragments. + +The Hare-footed Leaf-cutter (Megachile lagopoda, LIN.) which I see +very busy in my enclosure, though she only collects her materials +there, exploits the lilac and the rose-tree by preference. From time +to time, I see her also cutting bits out of the robinia, the quince- +tree and the cherry-tree. In the open country, I have found her +building with the leaves of the vine alone. + +The Silvery Leaf-cutter (Megachile argentata, FAB.), another of my +guests, shares the taste of the aforesaid for the lilac and the rose, +but her domain includes in addition the pomegranate-tree, the +bramble, the vine, the common dogwood and the cornelian cherry. + +The White-girdled Leaf-cutter likes the robinia, to which she adds, +in lavish proportions, the vine, the rose and the hawthorn and +sometimes, in moderation, the reed and the whitish-leaved rock-rose. + +The Black-tipped Leaf-cutter (Megachile apicalis, SPIN.) has for her +abode the cells of the Mason-bee of the Pebbles and the ruined nests +of the Osmiae and Anthidia in the Snail-shells. I have not known her +to use any other materials than the wild briar and the hawthorn. + +Incomplete though it be, this list tells us that the Megachiles do +not have exclusive botanical tastes. Each species manages extremely +well with several plants differing greatly in appearance. The first +condition to be fulfilled by the shrub exploited is that it be near +the nest. Frugal of her time, the Leaf-cutter declines to go on +distant expeditions. Whenever I come upon a recent Megachile-nest, I +am not long in finding in the neighbourhood, without much searching, +the tree or shrub from which the Bee has cut her pieces. + +Another main condition is a fine and supple texture, especially for +the first disks used in the lid and for the pieces which form the +lining of the wallet. The rest, less carefully executed, allows of +coarser stuff; but even then the piece must be flexible and lend +itself to the cylindrical configuration of the tunnel. The leaves of +the rock-roses, thick and roughly fluted, fulfil this condition +unsatisfactorily, for which reason I see them occurring only at very +rare intervals. The insect has gathered pieces of them by mistake +and, not finding them good to use, has ceased to visit the +unprofitable shrub. Stiffer still, the leaf of the holm-oak in its +full maturity is never employed: the Silky Leaf-cutter uses it only +in the young state and then in moderation; she can get her velvety +pieces better from the vine. In the lilac-bushes so zealously +exploited before my eyes by the Hare-footed Leaf-cutter occur a +medley of different shrubs which, from their size and the lustre of +their leaves, should apparently suit that sturdy pinker. They are the +shrubby hare's-ear, the honeysuckle, the prickly butcher's-broom, the +box. What magnificent disks ought to come from the hare's-ear and the +honeysuckle! One could get an excellent piece, without further +labour, by merely cutting the leaf-stalk of the box, as Megachile +sericans does with her paliurus. The lilac-lover disdains them +absolutely. For what reason? I fancy that she finds them too stiff. +Would she think differently if the lilac-bush were not there? Perhaps +so. + +In short, apart from the questions of texture and proximity to the +nest, the Megachile's choice, it seems to me, must depend upon +whether a particular shrub is plentiful or not. This would explain +the lavish use of the vine, an object of widespread cultivation, and +of the hawthorn and the wild briar, which form part of all our +hedges. As these are to be found everywhere, the fact that the +different Leaf-cutters make use of them is no reflection upon a host +of equivalents varying according to the locality. + +If we had to believe what people tell us about the effects of +heredity, which is said to hand down from generation to generation, +ever more firmly established, the individual habits of those who come +before, the Megachiles of these parts, experienced in the local flora +by the long training of the centuries, but complete novices in the +presence of plants which their race encounters for the first time, +ought to refuse as unusual and suspicious any exotic leaves, +especially when they have at hand plenty of the leaves made familiar +by hereditary custom. The question was deserving of separate study. + +Two subjects of my observations, the Hare-footed and the Silvery +Leaf-cutter, both of them inmates of my open-air laboratory, gave me +a definite answer. Knowing the points frequented by the two +Megachiles, I planted in their work-yard, overgrown with briar and +lilac, two outlandish plants which seemed to me to fulfil the +required conditions of suppleness of texture, namely, the ailantus, a +native of Japan, and the Virginian physostegia. Events justified the +selection: both Bees exploited the foreign flora with the same +assiduity as the local flora, passing from the lilac to the ailantus, +from the briar to the physostegia, leaving the one, going back to the +other, without drawing distinctions between the known and the +unknown. Inveterate habit could not have given greater certainty, +greater ease to their scissors, though this was their first +experience of such a material. + +The Silvery Leaf-cutter lent herself to an even more conclusive test. +As she readily makes her nest in the reeds of my apparatus, I was +able, up to a certain point, to create a landscape for her and select +its vegetation myself. I therefore moved the reed-hive to a part of +the enclosure stocked chiefly with rosemary, whose scanty foliage is +not adapted for the Bee's work, and near the apparatus I arranged an +exotic shrubbery in pots, including notably the smooth lopezia, from +Mexico, and the long-fruited capsicum, an Indian annual. Finding +close at hand the wherewithal to build her nest, the Leaf-cutter went +no further afield. The lopezia suited her especially, so much so that +almost the whole nest was composed of it. The rest had been gathered +from the capsicum. + +Another recruit, whose co-operation I had in no way engineered, came +spontaneously to offer me her evidence. This was the Feeble Leaf- +cutter (Megachile imbecilla, GERST.). Nearly a quarter of a century +ago, I saw her, all through the month of July, cutting out her rounds +and ellipses at the expense of the petals of the Pelargonium zonale, +the common geranium. Her perseverance devastated--there is no other +word for it--my modest array of pots. Hardly was a blossom out, when +the ardent Megachiles came and scalloped it into crescents. The +colour was indifferent to her: red, white or pink, all the petals +underwent the disastrous operation. A few captures, ancient relics of +my collecting-boxes by this time, indemnified me for the pillage. I +have not seen this unpleasant Bee since. With what does she build +when there are no geranium-flowers handy? I do not know; but the fact +remains that the fragile tailoress used to attack the foreign flower, +a fairly recent acquisition from the Cape, as though all her race had +never done anything else. + +These details leave us with one obvious conclusion, which is contrary +to our original ideas, based on the unvarying character of insect +industry. In constructing their jars, the Leaf-cutters, each +following the taste peculiar to her species, do not make use of this +or that plant to the exclusion of the others; they have no definite +flora, no domain faithfully transmitted by heredity. Their pieces of +leaves vary according to the surrounding vegetation; they vary in +different layers of the same cell. Everything suits them, exotic or +native, rare or common, provided that the bit cut out be easy to +employ. It is not the general aspect of the shrub, with its fragile +or bushy branches, its large or small, green or grey, dull or glossy +leaves, that guides the insect: such advanced botanical knowledge +does not enter into the question at all. In the thicket chosen as a +pinking-establishment, the Megachile sees but one thing: leaves +useful for her work. The Shrike, with his passion for plants with +long, woolly sprigs, knows where to find nicely-wadded substitutes +when his favourite growth, the cotton-rose, is lacking; the Megachile +has much wider resources: indifferent to the plant itself, she looks +only into the foliage. If she finds leaves of the proper size, of a +dry texture capable of defying the damp and of a suppleness +favourable to cylindrical curving, that is all she asks; and the rest +does not matter. She has therefore an almost unlimited field for her +labour. + +These sudden and wholly unprovoked changes give cause for reflection. +When my geranium-flowers were devastated, how had the obtrusive Bee, +untroubled by the profound dissimilarity between the petals, snow- +white here, bright scarlet there, how had she learnt her trade? +Nothing tells us that she herself was not for the first time +exploiting the plant from the Cape; and, if she really did have +predecessors, the habit had not had time to become inveterate, +considering the modern importation of the geranium. Where again did +the Silvery Megachile, for whom I created an exotic shrubbery, make +the acquaintance of the lopezia, which comes from Mexico? She +certainly is making a first start. Never did her village or mine +possess a stalk of that chilly denizen of our hot-houses. She is +making a first start; and behold her straightway a graduate, versed +in the art of carving unfamiliar foliage. + +People often talk of the long apprenticeships served by instinct, of +its gradual acquirements, of its talents, the laborious work of the +ages. The Megachiles affirm the exact opposite. They tell me that the +animal, though invariable in the essence of its art, is capable of +innovation in the details; but at the same time they assure me that +any such innovation is sudden and not gradual. Nothing prepares the +innovations, nothing improves them or hands them down; otherwise a +selection would long ago have been made amid the diversity of +foliage; and the shrub recognized as the most serviceable, especially +when it is also plentiful, would alone supply all the building- +materials needed. If heredity transmitted industrial discoveries, a +Megachile who thought of cutting her disks out of pomegranate-leaves +and found them satisfactory ought to have instilled a liking for +similar materials into her descendants; and we should this day find +Leaf-cutters faithful to the pomegranate-leaves, workers who remained +exclusive in their choice of the raw material. The facts refute these +theories. + +People also say: + +'Grant us a variation, however small, in the insect's industry; and +that variation, accentuated more and more, will produce a new race +and finally a fixed species.' + +This trifling variation is the fulcrum for which Archimedes clamoured +in order to lift the world with his system of levers. The Megachiles +offer us one and a very great one: the indefinite variation of their +materials. What will the theorists' levers lift with this fulcrum? +Why, nothing at all! Whether they cut the delicate petals of the +geranium or the tough leaves of the lilac-bushes, the Leaf-cutters +are and will be what they were. This is what we learn from the +persistence of each species in its structural details, despite the +great variety of the foliage employed. + + +CHAPTER 9. THE COTTON-BEES. + +The evidence of the Leaf-cutters proves that a certain latitude is +left to the insect in its choice of materials for the nest; and this +is confirmed by the testimony of the Anthidia, the cotton- +manufacturers. My district possesses five: A. Florentinum, LATR., A. +diadema, LATR., A. manicatum, LATR., A. cingulatum, LATR., A. +scapulare, LATR. None of them creates the refuge in which the cotton +goods are manufactured. Like the Osmiae and the Leaf-cutters, they +are homeless vagrants, adopting, each to her own taste, such shelter +as the work of others affords. The Scapular Anthidium is loyal to the +dry bramble, deprived of its pith and turned into a hollow tube by +the industry of various mining Bees, among which figure, in the front +rank, the Ceratinae, dwarf rivals of the Xylocopa, or Carpenter-bee, +that mighty driller of rotten wood. The spacious galleries of the +Masked Anthophora suit the Florentine Anthidium, the foremost member +of the genus so far as size is concerned. The Diadem Anthidium +considers that she has done very well if she inherits the vestibule +of the Hairy-footed Anthophora, or even the ordinary burrow of the +Earth-worm. Failing anything better, she may establish herself in the +dilapidated dome of the Mason-bee of the Pebbles. The Manicate +Anthidium shares her tastes. I have surprised the Girdled Anthidium +cohabiting with a Bembex-wasp. The two occupants of the cave dug in +the sand, the owner and the stranger, were living in peace, both +intent upon their business. Her usual habitation is some hole or +other in the crevices of a ruined wall. To these refuges, the work of +others, we can add the stumps of reeds, which are as popular with the +various cotton-gatherers as with the Osmiae; and, after we have +mentioned a few most unexpected retreats, such as the sheath provided +by a hollow brick or the labyrinth furnished by the lock of a gate, +we shall have almost exhausted the list of domiciles. + +Like the Osmiae and the Leaf-cutters, the Anthidium shows an urgent +need of a ready-made home. She never houses herself at her own +expense. Can we discover the reason? Let us first consult a few hard +workers who are artificers of their own dwellings. The Anthophora +digs corridors and cells in the road-side banks hardened by the sun; +she does not erect, she excavates; she does not build, she clears. +Toiling away with her mandibles, atom by atom, she manages to +contrive the passages and chambers necessary for her eggs; and a huge +business it is. She has, in addition, to polish and glaze the rough +sides of her tunnels. What would happen if, after obtaining a home by +dint of long-continued toil, she had next to line it with wadding, to +gather the fibrous down from cottony plants and to felt it into bags +suitable for the honey-paste? The hard-working Bee would not be equal +to producing all these refinements. Her mining calls for too great an +expenditure of time and strength to leave her the leisure for +luxurious furnishing. Chambers and corridors, therefore, will remain +bare. + +The Carpenter-bee gives us the same answer. When with her joiner's +wimble she has patiently bored the beam to a depth of nine inches, +would she be able to cut out and place in position the thousand and +one pieces which the Silky Leaf-cutter employs for her nest? Time +would fail her, even as it would fail a Megachile who, lacking the +Capricorn's chamber, had herself to dig a home in the trunk of the +oak. Therefore the Carpenter-bee, after the tedious work of boring, +gets the installation done in the most summary fashion, simply +running up a sawdust partition. + +The two things, the laborious business of obtaining a lodging and the +artistic work of furnishing, seem unable to go together. With the +insect as with man, he who builds the house does not furnish it, he +who furnishes it does not build it. To each his share, because of +lack of time. Division of labour, the mother of the arts, makes the +workman excel in his department; one man for the whole work would +mean stagnation, the worker never getting beyond his first crude +attempts. Animal industry is a little like our own: it does not +attain its perfection save with the aid of obscure toilers, who, +without knowing it, prepare the final masterpiece. I see no other +reason for this need of a gratuitous lodging for the Megachile's +leafy basket or the Anthidia's cotton purses. In the case of other +artists who handle delicate things that require protection, I do not +hesitate to assume the existence of a ready-made home. Thus Reaumur +tells us of the Upholsterer-bee, Anthocopa papaveris, who fashions +her cells with poppy-petals. I do not know the flower-cutter, I have +never seen her; but her art tells me plainly enough that she must +establish herself in some gallery wrought by others, as, for +instance, in an Earth-worm's burrow. + +We have but to see the nest of a Cotton-bee to convince ourselves +that its builder cannot at the same time be an indefatigable navvy. +When and newly-felted and not yet made sticky with honey, the wadded +purse is by far the most elegant known specimen of entomological +nest-building, especially where the cotton is of a brilliant white, +as is frequently the case in the manufacturers of the Girdled +Anthidium. No bird's-nest, however deserving of our admiration, can +vie in fineness of flock, in gracefulness of form, in delicacy of +felting with this wonderful bag, which our fingers, even with the aid +of tools, could hardly imitate, for all their dexterity. I abandon +the attempt to understand how, with its little bales of cotton +brought up one by one, the insect, no otherwise gifted than the +kneaders of mud and the makers of leafy baskets, manages to felt what +it has collected into a homogeneous whole and then to work the +product into a thimble-shaped wallet. Its tools as a master-fuller +are its legs and its mandibles, which are just like those possessed +by the mortar-kneaders and Leaf-cutters; and yet, despite this +similarity of outfit, what a vast difference in the results obtained! + +To see the Cotton-bees' talents in action seems an undertaking +fraught with innumerable difficulties: things happen at a depth +inaccessible to the eye; and to persuade the insect to work in the +open does not lie in our power. One resource remained and I did not +fail to turn to it, though hitherto I have been wholly unsuccessful. +Three species, Anthidium diadema, A. manicatum and A. florentinum-- +the first-named in particular--show themselves quite ready to take up +their abode in my reed-apparatus. All that I had to do was to replace +the reeds by glass tubes, which would allow me to watch the work +without disturbing the insect. This stratagem had answered perfectly +with the Three-horned Osmia and Latreille's Osmia, whose little +housekeeping-secrets I had learnt thanks to the transparent dwelling- +house. Why should it not answer for its Cotton-bees and, in the same +way, with the Leaf-cutters? I almost counted on success. Events +betrayed my confidence. For four years I supplied my hives with glass +tubes and not once did the Cotton-weavers or the Leaf-cutters +condescend to take up their quarters in the crystal palaces. They +always preferred the hovel provided by the reed. Shall I persuade +them one day? I do not abandon all hope. + +Meanwhile, let me describe the little that I saw. More or less +stocked with cells, the reed is at last closed, right at the orifice, +with a thick plug of cotton, usually coarser than the wadding of the +honey-satchels. It is the equivalent of the Three-horned Osmia's +barricade of mud, of the leaf-putty of Latreille's Osmia, of the +Megachiles' barrier of leaves cut into disks. All these free tenants +are careful to shut tight the door of the dwelling, of which they +have often utilized only a portion. To watch the building of this +barricade, which is almost external work, demands but a little +patience in waiting for the favourable moment. + +The Anthidium arrives at last, carrying the bale of cotton for the +plugging. With her fore-legs she tears it apart and spreads it out; +with her mandibles, which go in closed and come out open, she loosens +the hard lumps of flock; with her forehead she presses each new layer +upon the one below. And that is all. The insect flies off, returns +the richer by another bale and repeats the performance until the +cotton barrier reaches the level of the opening. We have here, +remember, a rough task, in no way to be compared with the delicate +manufacturer of the bags; nevertheless, it may perhaps tell us +something of the general procedure of the finer work. The legs do the +carding, the mandibles the dividing, the forehead the pressing; and +the play of these implements produces the wonderful cushioned wallet. +That is the mechanism in the lump; but what of the artistry? + +Let us leave the unknown for facts within the scope of observation. I +will question the Diadem Anthidium in particular, a frequent inmate +of my reeds. I open a reed-stump about two decimetres long by twelve +millimetres in diameter. (About seven and three-quarter inches by +half an inch.--Translator's Note.) The end is occupied by a column of +cotton-wool comprising ten cells, without any demarcation between +them on the outside, so that their whole forms a continuous cylinder. +Moreover, thanks to a close felting, the different compartments are +soldered together, so much so that, when pulled by the end, the +cotton edifice does not break into sections, but comes out all in one +piece. One would take it for a single cylinder, whereas in reality +the work is composed of a series of chambers, each of which has been +constructed separately, independently of the one before, except +perhaps at the base. + +For this reason, short of ripping up the soft dwelling, still full of +honey, it is impossible to ascertain the number of storeys; we must +wait until the cocoons are woven. Then our fingers can tell the cells +by counting the knots that resist pressure under the cover of +wadding. This general structure is easily explained. A cotton bag is +made, with the sheath of the reed as a mould. If this guiding sheath +were lacking, the thimble shape would be obtained all the same, with +no less elegance, as is proved by the Girdled Anthidium, who makes +her nest in some hiding-place or other in the walls or the ground. +When the purse is finished, the provisions come and the egg, followed +by the closing of the cell. We do not here find the geometrical lid +of the Leaf-cutters, the pile of disks tight-set in the mouth of the +jar. The bag is closed with a cotton sheet whose edges are soldered +by a felting-process to the edges of the opening. The soldering is so +well done that the honey-pouch and its cover form an indivisible +whole. Immediately above it, the second cell is constructed, having +its own base. At the beginning of this work, the insect takes care to +join the two storeys by felting the ceiling of the first to the floor +of the second. Thus continued to the end, the work, with its inner +solderings, becomes an unbroken cylinder, in which the beauties of +the separate wallets disappear from view. In very much the same +fashion, but with less adhesion among the different cells, do the +Leaf-cutters act when stacking their jars in a column without any +external division into storeys. + +Let us return to the reed-stump which gives us these details. Beyond +the cotton-wool cylinder wherein ten cocoons are lodged in a row +comes an empty space of half a decimetre or more. (About two inches.- +-Translator's Note.) The Osmiae and the Leaf-cutters are also +accustomed to leave these long, deserted vestibules. The nest ends, +at the orifice of the reed, with a strong plug of flock coarser and +less white than that of the cells. This use of closing-materials +which are less delicate in texture but of greater resisting-power, +while not an invariable characteristic, occurs frequently enough to +make us suspect that the insect knows how to distinguish what is best +suited now to the snug sleeping-berth of the larvae, anon to the +defensive barricade of the home. Sometimes the choice is an +exceedingly judicious one, as is shown by the nest of the Diadem +Anthidium. Time after time, whereas the cells were composed of the +finest grade of white cotton, gathered from Centaurea solsticialis, +or St. Barnaby's thistle, the barrier at the entrance, differing from +the rest of the work in its yellow colouring, was a heap of close-set +bristles supplied by the scallop-leaved mullein. The two functions of +the wadding are here plainly marked. The delicate skin of the larvae +needs a well-padded cradle; and the mother collects the softest +materials that the cottony plants provide. Rivalling the bird, which +furnishes the inside of the nest with wool and strengthens the +outside with sticks, she reserves for the grubs' mattress the finest +down, so hard to find and collected with such patience. But, when it +becomes a matter of shutting the door against the foe, then the +entrance bristles with forbidding caltrops, with stiff, prickly +hairs. + +This ingenious system of defence is not the only one known to the +Anthidia. More distrustful still, the Manicate Anthidium leaves no +space in the front part of the reed. Immediately after the column of +cells, she heaps up, in the uninhabited vestibule, a conglomeration +of rubbish, whatever chance may offer in the neighbourhood of the +nest: little pieces of gravel, bits of earth, grains of sawdust, +particles of mortar, cypress-catkins, broken leaves, dry Snail- +droppings and any other material that comes her way. The pile, a real +barricade this time, blocks the reed completely to the end, except +about two centimetres (About three-quarters of an inch.--Translator's +Note.) left for the final cotton plug. Certainly no foe will break in +through the double rampart; but he will make an insidious attack from +the rear. The Leucopsis will come and, with her long probe, thanks to +some imperceptible fissure in the tube, will insert her dread eggs +and destroy every single inhabitant of the fortress. Thus are the +Manicate Anthidium's anxious precautions outwitted. + +If we had not already seen the same thing with the Leaf-cutters, this +would be the place to enlarge upon the useless tasks undertaken by +the insect when, with its ovaries apparently depleted, it goes on +spending its strength with no maternal object in view and for the +sole pleasure of work. I have come across several reeds stopped up +with flock though containing nothing at all, or else furnished with +one, two or three cells devoid of provisions or eggs. The ever- +imperious instinct for gathering cotton and felting it into purses +and heaping it into barricades persists, fruitlessly, until life +fails. The Lizard's tail wriggles, curls and uncurls after it is +detached from the animal's body. In these reflex movements, I seem to +see not an explanation, certainly, but a rough image of the +industrious persistency of the insect, still toiling away at its +business, even when there is nothing useful left to do. This worker +knows no rest but death. + +I have said enough about the dwelling of the Diadem Anthidium; let us +look at the inhabitant and her provisions. The honey is pale-yellow, +homogeneous and of a semifluid consistency, which prevents it from +trickling through the porous cotton bag. The egg floats on the +surface of the heap, with the end containing the head dipped into the +paste. To follow the larva through its progressive stages is not +without interest, especially on account of the cocoon, which is one +of the most singular that I know. With this object in view, I prepare +a few cells that lend themselves to observation. I take a pair of +scissors, slice a piece off the side of the cotton-wool purse, so as +to lay bare both the victuals and the consumer, and place the ripped +cell in a short glass tube. During the first few days, nothing +striking happens. The little grub, with its head still plunged in the +honey, slakes its thirst with long draughts and waxes fat. A moment +comes...But let us go back a little farther, before broaching this +question of sanitation. + +Every grub, of whatever kind, fed on provisions collected by the +mother and placed in a narrow cell is subject to conditions of health +unknown to the roving grub that goes where it likes and feeds itself +on what it can pick up. The first, the recluse, is no more able than +the second, the gadabout, to solve the problem of a food which can be +entirely assimilated, without leaving an unclean residue. The second +gives no thought to these sordid matters: any place suits it for +getting rid of that difficulty. But what will the other do with its +waste matter, cooped up as it is in a tiny cell stuffed full of +provisions? A most unpleasant mixture seems inevitable. Picture the +honey-eating grub floating on liquid provisions and fouling them at +intervals with its excretions! The least movement of the hinder-part +would cause the whole to amalgamate; and what a broth that would make +for the delicate nursling! No, it cannot be; those dainty epicures +must have some method of escaping these horrors. + +They all have, in fact, and most original methods at that. Some take +the bull by the horns, so to speak, and, in order not to soil things, +refrain from uncleanliness until the end of the meal: they keep the +dropping-trap closed as long as the victuals are unfinished. This is +a radical scheme, but not in every one's power, it appears. It is the +course adopted, for instance, by the Sphex-wasps and the Anthophora- +bees, who, when the whole of the food is consumed, expel at one shot +the residues amassed in the intestines since the commencement of the +repast. + +Others, the Osmiae in particular, accept a compromise and begin to +relieve the digestive tract when a suitable space has been made in +the cell through the gradual disappearance of the victuals. Others +again--more hurried these--find means of obeying the common law +pretty early by engaging in stercoral manufactures. By a stroke of +genius, they make the unpleasant obstruction into building-bricks. We +already know the art of the Lily-beetle (Crioceris merdigera. Fabre's +essay on this insect has not yet been translated into English; but +readers interested in the matter will find a full description in "An +Introduction to Entomology," by William Kirby, Rector of Barham, and +William Spence: letter 21.--Translator's Note.), who, with her soft +excrement, makes herself a coat wherein to keep cool in spite of the +sun. It is a very crude and revolting art, disgusting to the eye. The +Diadem Anthidium belongs to another school. With her droppings she +fashions masterpieces of marquetry and mosaic, which wholly conceal +their base origin from the onlooker. Let us watch her labours through +the windows of my tubes. + +When the portion of food is nearly half consumed, there begins and +goes on to the end a frequent defecation of yellowish droppings, each +hardly the size of a pin's head. As these are ejected, the grub +pushes them back to the circumference of the cell with a movement of +its hinder-part and keeps them there by means of a few threads of +silk. The work of the spinnerets, therefore, which is deferred in the +others until the provisions are finished, starts earlier here and +alternates with the feeding. In this way, the excretions are kept at +a distance, away from the honey and without any danger of getting +mixed with it. They end by becoming so numerous as to form an almost +continuous screen around the larva. This excremental awning, made +half of silk and half of droppings, is the rough draft of the cocoon, +or rather a sort of scaffolding on which the stones are deposited +until they are definitely placed in position. Pending the piecing +together of the mosaic, the scaffolding keeps the victuals free from +all contamination. + +To get rid of what cannot be flung outside, by hanging it on the +ceiling, is not bad to begin with; but to use it for making a work of +art is better still. The honey has disappeared. Now commences the +final weaving of the cocoon. The grub surrounds itself with a wall of +silk, first pure white, then tinted reddish-brown by means of an +adhesive varnish. Through its loose-meshed stuff, it seizes one by +one the droppings hanging from the scaffold and inlays them firmly in +the tissue. The same mode of work is employed by the Bembex-, Stizus- +and Tachytes-wasps and other inlayers, who strengthen the inadequate +woof of their cocoons with grains of sand; only, in their cotton-wool +purses, the Anthidium's grubs substitute for the mineral particles +the only solid materials at their disposal. For them, excrement takes +the place of pebbles. + +And the work goes none the worse for it. On the contrary: when the +cocoon is finished, any one who had not witnessed the process of +manufacture would be greatly puzzled to state the nature of the +workmanship. The colouring and the elegant regularity of the outer +wrapper of the cocoon suggest some kind of basket-work made with tiny +bits of bamboo, or a marquetry of exotic granules. I too let myself +be caught by it in my early days and wondered in vain what the hermit +of the cotton wallet had used to inlay her nymphal dwelling so +prettily withal. To-day, when the secret is known to me, I admire the +ingenuity of the insect capable of obtaining the useful and the +beautiful out of the basest materials. + +The cocoon has another surprise in store for us. The end containing +the head finishes with a short conical nipple, an apex, pierced by a +narrow shaft that establishes a communication between the inside and +the out. This architectural feature is common to all the Anthidia, to +the resin-workers who will occupy our attention presently, as well as +to the cotton-workers. It is found nowhere outside the Anthidium +group. + +What is the use of this point which the larva leaves bare instead of +inlaying it like the rest of the shell? What is the use of that hole, +left quite open or, at most, closed at the bottom with a feeble +grating of silk? The insect appears to attach great importance to it, +from what I see. In point of fact, I watch the careful work of the +apex. The grub, whose movements the hole enables me to follow, +patiently perfects the lower end of the conical channel, polishes it +and gives it an exactly circular shape; from time to time, it inserts +into the passage its two closed mandibles, whose points project a +little way outside; then, opening them to a definite radius, like a +pair of compasses, it widens the aperture and makes it regular. + +I imagine, without venturing, however, to make a categorical +statement, that the perforated apex is a chimney to admit the air +required for breathing. Every pupa breathes in its shell, however +compact this may be, even as the unhatched bird breathes inside the +egg. The thousands of pores with which the shell is pierced allow the +inside moisture to evaporate and the outer air to penetrate as and +when needed. The stony caskets of the Bembex- and Stizus-wasps are +endowed, notwithstanding their hardness, with similar means of +exchange between the vitiated and the pure atmosphere. Can the shells +of the Anthidia be air-proof, owing to some modification that escapes +me? In any case, this impermeability cannot be attributed to the +excremental mosaic, which the cocoons of the resin-working Anthidia +do not possess, though endowed with an apex of the very best. + +Shall we find an answer to the question in the varnish with which the +silken fabric is impregnated? I hesitate to say yes and I hesitate to +say no, for a host of cocoons are coated with a similar lacquer +though deprived of communication with the outside air. All said, +without being able at present to account for its necessity, I admit +that the apex of the Anthidia is a breathing-aperture. I bequeath to +the future the task of telling us for what reasons the collectors of +both cotton and resin leave a large pore in their shells, whereas all +the other weavers close theirs completely. + +After these biological curiosities, it remains for me to discuss the +principal subject of this chapter: the botanical origin of the +materials of the nest. By watching the insect when busy at its +harvesting, or else by examining its manufactured flock under the +microscope, I was able to learn, not without a great expenditure of +time and patience, that the different Anthidia of my neighbourhood +have recourse without distinction to any cottony plant. Most of the +wadding is supplied by the Compositae, particularly the following: +Centaurea solsticialis, or St. Barnaby's thistle; C. paniculata, or +panicled centaury; Echinops ritro, or small globe-thistle; Onopordon +illyricum, or Illyrian cotton-thistle; Helichrysum staechas, or wild +everlasting; Filago germanica, or common cotton-rose. Next come the +Labiatae: Marrubium vulgare, or common white horehound; Ballota +fetida, or stinking horehound; Calamintha nepeta, or lesser calamint; +Salvia aethiopis, or woolly sage. Lastly, the Solanaceae: Verbascum +thapsus, or shepherd's club; V. sinuatum, or scollop-leaved mullein. + +The Cotton-bees' flora, we see, incomplete as it is in my notes, +embraces plants of very different aspect. There is no resemblance in +appearance between the proud candelabrum of the cotton-thistle, with +its red tufts, and the humble stalk of the globe-thistle, with its +sky-blue capitula; between the plentiful leaves of the mullein and +the scanty foliage of the St. Barnaby's thistle; between the rich +silvery fleece of the woolly sage and the short hairs of the +everlasting. With the Anthidium, these clumsy botanical +characteristics do not count; one thing alone guides her: the +presence of cotton. Provided that the plant be more or less well- +covered with soft wadding, the rest is immaterial to her. + +Another condition, however, has to be fulfilled, apart from the +fineness of the cotton-wool. The plant, to be worth shearing, must be +dead and dry. I have never seen the harvesting done on fresh plants. +In this way, the Bee avoids mildew, which would make its appearance +in a mass of hairs still filled with sap. + +Faithful to the plant recognized as yielding good results, the +Anthidium arrives and resumes her gleaning on the edges of the parts +denuded by earlier harvests. Her mandibles scrape away and pass the +tiny fluffs, one by one, to the hind-legs, which hold the pellet +pressed against the chest, mix with it the rapidly-increasing store +of down and make the whole into a little ball. When this is the size +of a pea, it goes back into the mandibles; and the insect flies off, +with its bale of cotton in its mouth. If we have the patience to +wait, we shall see it return to the same point, at intervals of a few +minutes, so long as the bag is not made. The foraging for provisions +will suspend the collecting of cotton; then, next day or the day +after, the scraping will be resumed on the same stalk, on the same +leaf, if the fleece be not exhausted. The owner of a rich crop +appears to keep to it until the closing-plug calls for coarser +materials; and even then this plug is often manufactured with the +same fine flock as the cells. + +After ascertaining the diversity of cotton-fields among our native +plants, I naturally had to enquire whether the Cotton-bee would also +put up with exotic plants, unknown to her race; whether the insect +would show any hesitation in the presence of woolly plants offered +for the first time to the rakes of her mandibles. The common clary +and the Babylonian centaury, with which I have stocked the harmas, +shall be the harvest-fields; the reaper shall be the Diadem +Anthidium, the inmate of my reeds. + +The common clary, or toute-bonne, forms part, I know, of our French +flora to-day; but it is an acclimatized foreigner. They say that a +gallant crusader, returning from Palestine with his share of glory +and bruises, brought back the toute-bonne from the Levant to help him +cure his rheumatism and dress his wounds. From the lordly manor, the +plant propagated itself in all directions, while remaining faithful +to the walls under whose shelter the noble dames of yore used to grow +it for their unguents. To this day, feudal ruins are its favourite +resorts. Crusaders and manors disappeared; the plant remained. In +this case, the origin of the clary, whether historical or legendary, +is of secondary importance. Even if it were of spontaneous growth in +certain parts of France, the toute-bonne is undoubtedly a stranger in +the Vaucluse district. Only once in the course of my long botanizing- +expeditions across the department have I come upon this plant. It was +at Caromb, in some ruins, nearly thirty years ago. I took a cutting +of it; and since then the crusaders' sage has accompanied me on all +my peregrinations. My present hermitage possesses several tufts of +it: but, outside the enclosure, except at the foot of the walls, it +would be impossible to find one. We have, therefore, a plant that is +new to the country for many miles around, a cotton-field which the +Serignan Cotton-bees had never utilized before I came and sowed it. + +Nor had they ever made use of the Babylonian centaury, which I was +the first to introduce in order to cover my ungrateful stony soil +with some little vegetation. They had never seen anything like the +colossal centaury imported from the region of the Euphrates. Nothing +in the local flora, not even the cotton-thistle, had prepared them +for this stalk as thick as a child's wrist, crowned at a height of +nine feet with a multitude of yellow balls, nor for those great +leaves spreading over the ground in an enormous rosette. What will +they do in the presence of such a find? They will take possession of +it with no more hesitation than if it were the humble St. Barnaby's +thistle, the usual purveyor. + +In fact, I place a few stalks of clary and Babylonian centaury, duly +dried, near the reed-hives. The Diadem Anthidium is not long in +discovering the rich harvest. Straight away the wool is recognized as +being of excellent quality, so much so that, during the three or four +weeks of nest-building, I can daily witness the gleaning, now on the +clary, now on the centaury. Nevertheless the Babylonian plant appears +to be preferred, no doubt because of its whiter, finer and more +plentiful down. I keep a watchful eye on the scraping of the +mandibles and the work of the legs as they prepare the pellet; and I +see nothing that differs from the operations of the insect when +gleaning on the globe-thistle and the St. Barnaby's thistle. The +plant from the Euphrates and the plant from Palestine are treated +like those of the district. + +Thus we find what the Leaf-cutters taught us proved, in another way, +by the cotton-gatherers. In the local flora, the insect has no +precise domain; it reaps its harvest readily now from one species, +now from another, provided that it find the materials for its +manufactures. The exotic plant is accepted quite as easily as that of +indigenous growth. Lastly, the change from one plant to another, from +the common to the rare, from the habitual to the exceptional, from +the known to the unknown, is made suddenly, without gradual +initiations. There is no novitiate, no training by habit in the +choice of the materials for the nest. The insect's industry, variable +in its details by sudden, individual and non-transmissible +innovations, gives the lie to the two great factors of evolution: +time and heredity. + + +CHAPTER 10. THE RESIN-BEES. + +At the time when Fabricius (Johann Christian Fabricius (1745-1808), a +noted Danish entomologist, author of "Systema entomologiae" (1775).-- +Translator's Note.) gave the genus Anthidium its name, a name still +used in our classifications, entomologists troubled very little about +the live animal; they worked on corpses, a dissecting-room method +which does not yet seem to be drawing to an end. They would examine +with a conscientious eye the antenna, the mandible, the wing, the +leg, without asking themselves what use the insect had made of those +organs in the exercise of its calling. The animal was classified very +nearly after the manner adopted in crystallography. Structure was +everything; life, with its highest prerogatives, intellect, instinct, +did not count, was not worthy of admission into the zoological +scheme. + +It is true that an almost exclusively necrological study is +obligatory at first. To fill one's boxes with insects stuck on pins +is an operation within the reach of all; to watch those same insects +in their mode of life, their work, their habits and customs is quite +a different thing. The nomenclator who lacks the time--and sometimes +also the inclination--takes his magnifying-glass, analyzes the dead +body and names the worker without knowing its work. Hence the number +of appellations the least of whose faults is that they are unpleasant +to the ear, certain of them, indeed, being gross misnomers. Have we +not, for instance, seen the name of Lithurgus, or stone-worker, given +to a Bee who works in wood and nothing but wood? Such absurdities +will be inevitable until the animal's profession is sufficiently +familiar to lend its aid in the compiling of diagnoses. I trust that +the future will see this magnificent advance in entomological +science: men will reflect that the impaled specimens in our +collections once lived and followed a trade; and anatomy will be kept +in its proper place and made to leave due room for biology. + +Fabricius did not commit himself with his expression Anthidium, which +alludes to the love of flowers, but neither did he mention anything +characteristic: as all Bees have the same passion in a very high +degree, I see no reason to treat the Anthidia as more zealous looters +than the others. If he had known their cotton nests, perhaps the +Scandinavian naturalist would have given them a more logical +denomination. As for me, in a language wherein technical parade is +out of place, I will call them the Cotton-bees. + +The term requires some limiting. To judge by my finds, in fact, the +old genus Anthidium, that of the classifying entomologists, comprises +in my district two very different corporations. One is known to us +and works exclusively in wadding; the other, which we are about to +study, works in resin, without ever having recourse to cotton. +Faithful to my extremely simple principle of defining the worker, as +far as possible, by his work, I will call the members of this guild +the Resin-bees. Thus confining myself to the data supplied by my +observations, I divide the Anthidium group into equal sections, of +equal importance, for which I demand special generic titles; for it +is highly illogical to call the carders of wool and the kneaders of +resin by the same name. I surrender to those whom it concerns the +honour of effecting this reform in the orthodox fashion. + +Good luck, the friend of the persevering, made me acquainted in +different parts of Vaucluse with four Resin-bees whose singular trade +no one had yet suspected. To-day, I find them all four again in my +own neighbourhood. They are the following: Anthidium septemdentatum, +LATR., A. bellicosum, LEP., A. quadrilobum, LEP., and A. Latreillii, +LEP. The first two make their nests in deserted Snail-shells; the +other two shelter their groups of cells sometimes in the ground, +sometimes under a large stone. We will first discuss the inhabitants +of the Snail-shell. I made a brief reference to them in an earlier +chapter, when speaking of the distribution of the sexes. This mere +allusion, suggested by a study of a different kind, must now be +amplified. I return to it with fuller particulars. + +The stone-heaps in the Roman quarries near Serignan, which I have so +often visited in search of the nests of the Osmia who takes up her +abode in Snail-shells, supply me also with the two Resin-bees +installed in similar quarters. When the Field-mouse has left behind +him a rich collection of empty shells scattered all round his hay +mattress under the slab, there is always a hope of finding some +Snail-shells plugged with mud and, here and there, mixed with them, a +few Snail-shells closed with resin. The two Bees work next door to +each other, one using clay, the other gum. The excellence of the +locality is responsible for this frequent cohabitation, shelter being +provided by the broken stone from the quarry and lodgings by the +shells which the Mouse has left behind. + +At places where dead Snail-shells are few and far between, as in the +crevices of rustic walls, each Bee occupies by herself the shells +which she has found. But here, in the quarries, our crop will +certainly be a double or even a treble one, for both Resin-bees +frequent the same heaps. Let us, therefore, lift the stones and dig +into the mound until the excessive dampness of the subsoil tells us +that it is useless to look lower down. Sometimes at the moment of +removing the first layer, sometimes at a depth of eighteen inches, we +shall find the Osmia's Snail-shell and, much more rarely, the Resin- +bee's. Above all, patience! The job is none of the most fruitful; +nor is it exactly an agreeable one. By dint of turning over +uncommonly jagged stones, our fingertips get hurt, lose their skin +and become as smooth as though we had held them on a grindstone. +After a whole afternoon of this work, our back will be aching, our +fingers will be itching and smarting and we shall possess a dozen +Osmia-nests and perhaps two or three Resin-bees' nests. Let us be +content with that. + +The Osmia's shells can be recognized at once, as being closed at the +orifice with a clay cover. The Anthidium's call for a special +examination, without which we should run a great risk of filling our +pockets with cumbersome rubbish. We find a dead Snail-shell among the +stones. Is it inhabited by the Resin-bee or not? The outside tells us +nothing. The Anthidium's work comes at the bottom of the spiral, a +long way from the mouth; and, though this is wide open, the eye +cannot travel far enough along the winding stair. I hold up the +doubtful shell to the light. If it is completely transparent, I know +that it is empty and I put it back to serve for future nests. If the +second whorl is opaque, the spiral contains something. What does it +contain? Earth washed in by the rain? Remnants of the putrefied +Snail? That remains to be seen. With a little pocket-trowel, the +inquisitorial implement which always accompanies me, I make a wide +window in the middle of the final whorl. If I see a gleaming resin +floor, with incrustations of gravel, the thing is settled: I possess +an Anthidium's nest. But, oh the number of failures that go to one +success! The number of windows vainly opened in shells whose bottom +is stuffed with clay or with noisome corpses! Thus picking shells +among the overturned stone-heaps, inspecting them in the sun, +breaking into them with the trowel and nearly always rejecting them, +I manage, after repeated attempts, to obtain my materials for this +chapter. + +The first to hatch is the Seven-pronged Resin-bee (Anthidium +septemdentatum). We see her, in the month of April, lumbering along +to the rubbish-heaps in the quarries and the low boundary-walls, in +search of her Snail-shell. She is a contemporary of the Three-horned +Osmia, who begins operations in the last week of April, and often +occupies the same stone-heap, settling in the next shell. She is +well-advised to start work early and to be on neighbourly terms with +the Osmia when the latter is building; in fact, we shall soon see the +terrible dangers to which that same proximity exposes her dilatory +rival in resin-work, Anthidium bellicosum. + +The shell adopted in the great majority of cases is that of the +Common Snail, Helix aspersa. It is sometimes of full size, sometimes +half-developed. Helix nemoralis and H. caespitum, which are much +smaller, also supply suitable lodgings; and this would as surely +apply to any shell of sufficient capacity, if the places which I +explore possessed others, as witness a nest which my son Emile has +sent me from somewhere near Marseilles. This time, the Resin-bee is +settled in Helix algira, the most remarkable of our land-shells +because of the width and regularity of its spiral, which is copied +from that of the Ammonites. This magnificent nest, a perfect specimen +of both the Snail's work and the Bee's, deserves description before +any other. + +For a distance of three centimetres (1.17 inches.--Translator's +Note.) from the mouth, the last spiral whorl contains nothing. At +this inconsiderable depth, a partition is clearly seen. The moderate +diameter of the passage accounts for the Anthidium's choice of this +site to which our eye can penetrate. In the common Snail-shell, whose +cavity widens rapidly, the insect establishes itself much farther +back, so that, in order to see the terminal partition, we must, as I +have said, make a lateral inlet. The position of this boundary- +ceiling, which may come farther forward or farther back, depends on +the variable diameter of the passage. The cells of the cocoons +require a certain length and a certain breadth, which the mother +finds by going higher up or lower down in the spiral, according to +the shape of the shell. When the diameter is suitable, the last whorl +is occupied up to the orifice, where the final lid appears, +absolutely exposed to view. This is the case with the adult Helix +nemoralis and H. caespitum, and also with the young Common Snail. We +will not linger at present over this peculiarity, the importance of +which will become manifest shortly. + +Whether in the front or at the back of the spiral slope, the insect's +work ends in a facade of coarse mosaic, formed of small, angular bits +of gravel, firmly cemented with a gum the nature of which has to be +ascertained. It is an amber-coloured material, semi-transparent, +brittle, soluble in spirits of wine and burning with a sooty flame +and a strong smell of resin. From these characteristics it is evident +that the Bee prepares her gum with the resinous drops exuded by the +Coniferae. + +I think that I am even able to name the particular plant, though I +have never caught the insect in the act of gathering its materials. +Hard by the stone-heaps which I turn over for my collections there is +a plentiful supply of brown-berried junipers. Pines are totally +absent; and the cypress only appears occasionally near the houses. +Moreover, among the vegetable remains which we shall see assisting in +the protection of the nest, we often find the juniper's catkins and +needles. As the resin-insect is economical of its time and does not +fly far from the quarters familiar to it, the gum must have been +collected on the shrub at whose foot the materials for the barricade +have been gathered. Nor is this merely a local circumstance, for the +Marseilles nest abounds in similar remnants. I therefore regard the +juniper as the regular resin-purveyor, without, however, excluding +the pine, the cypress and other Coniferae when the favourite shrub is +absent. + +The bits of gravel in the lid are angular and chalky in the +Marseilles nest; they are round and flinty in most of the Serignan +nests. In making her mosaic, the worker pays no heed to the form or +colour of its component parts; she collects indiscriminately anything +that is hard enough and not too large. Sometimes she lights upon +treasures that give her work a more original character. The +Marseilles nest shows me, neatly encrusted amid the bits of gravel, a +tiny whole landshell, Pupa cineres. A nest in my own neighbourhood +provides me with a pretty Snail-shell, Helix striata, forming a rose- +pattern in the middle of the mosaic. These little artistic details +remind me of a certain nest of Eumenes Amadei (A Mason-wasp, forming +the subject of an essay which has not yet been published in English.- +-Translator's Note.) which abounds in small shells. Ornamental shell- +work appears to number its lovers among the insects. + +After the lid of resin and gravel, an entire whorl of the spiral is +occupied by a barricade of incongruous remnants, similar to that +which, in the reeds, protects the row of cocoons of the Manicate +Cotton-bee. It is curious to see exactly the same defensive methods +employed by two builders of such different talents, one of whom +handles flock, the other gum. The nest from Marseilles has for its +barricade bits of chalky gravel, particles of earth, fragments of +sticks, a few scraps of moss and especially juniper-catkins and +needles. The Serignan nests, installed in Helix aspersa, have almost +the same protective materials. I see bits of gravel, the size of a +lentil, and the catkins and needles of the brown-berried juniper +predominating. Next come the dry excretions of the Snail and a few +rare little land-shells. A similar jumble of more or less everything +found near the nest forms, as we know, the barricade of the Manicate +Cotton-bee, who is also an adept at using the Snail's stercoral +droppings after these have been dried in the sun. Let us observe +finally that these dissimilar materials are heaped together without +any cementing, just as the insect has picked them up. Resin plays no +part in the mass; and we have only to pierce the lid and turn the +shell upside down for the barricade to come dribbling to the ground. +To glue the whole thing together does not enter into the Resin-bee's +scheme. Perhaps such an expenditure of gum is beyond her means; +perhaps the barricade, if hardened into a solid block, would +afterwards form an invincible obstacle to the escape of the +youngsters; perhaps again the mass of gravel is an accessory rampart, +run up roughly as a work of secondary importance. + +Amid these doubtful matters, I see at least that the insect does not +look upon its barricade as indispensable. It employs it regularly in +the large shells, whose last whorl, too spacious to be used, forms an +unoccupied vestibule; it neglects it in the moderate shells, such as +Helix nemoralis, in which the resin lid is level with the orifice. My +excavations in the stone-heaps supply me with an almost equal number +of nests with and without defensive embankments. Among the Cotton- +bees, the Manicate Anthidium is not faithful either to her fort of +little sticks and stones; I know some of her nests in which cotton +serves every purpose. With both of them, the gravel rampart seems +useful only in certain circumstances, which I am unable to specify. + +On the other side of the outworks of the fortification, the lid and +barricade, are the cells set more or less far down in the spiral, +according to the diameter of the shell. They are bounded back and +front by partitions of pure resin, without any encrustations of +mineral particles. Their number is exceedingly restricted and is +usually limited to two. The front room, which is larger because the +width of the passage goes on increasing, is the abode of a male, +superior in size to the other sex; the less spacious back room +contains a female. I have already drawn attention in an earlier +chapter to the wonderful problem submitted for our consideration by +this breaking up of the laying into couples and this alternation of +the males and females. Without calling for other work than the +transverse partitions, the broadening stairway of the Snail-shell +thus furnishes both sexes with house-room suited to their size. + +The second Resin-bee that inhabits shells, Anthidium bellicosum, +hatches in July and works during the fierce heat of August. Her +architecture differs in no wise from that of her kinswoman of the +springtime, so much so that, when we find a tenanted Snail-shell in a +hole in the wall or under the stones, it is impossible to decide to +which of the two species the nest belongs. The only way to obtain +exact information is to break the shell and split the cocoons in +February, at which time the nests of the summer Resin-bee are +occupied by larvae and those of the spring Resin-bee by the perfect +insect. If we shrink from this brutal method, we are still in doubt +until the cocoons open, so great is the resemblance between the two +pieces of work. + +In both cases, we find the same lodging, Snail-shells of every size +and every kind, just as they happen to come; the same resin lid, the +inside gritty with tiny bits of stone, the outside almost smooth and +sometimes ornamented with little shells; the same barricade--not +always present--of various kinds of rubbish; the same division into +two rooms of unequal size occupied by the two sexes. Everything is +identical, down to the purveyor of the gum, the brown-berried +juniper. To say more about the nest of the summer Resin-bee would be +to repeat oneself. + +There is only one thing that requires further investigation. I do not +see the reason that prompts the two insects to leave the greater part +of their shell empty in front, instead of occupying it entirely up to +the orifice as the Osmia habitually does. As the mother's laying is +broken up into intermittent shifts of a couple of eggs apiece, is it +necessary that there should be a new home for each shift? Is the +half-fluid resin unsuitable for the wide-spanned roofs which would +have to be constructed when the diameter of the helical passage +exceeded certain limits? Is the gathering of the cement too wearisome +a task to leave the Bee any strength for making the numerous +partitions which she would need if she utilized the spacious final +whorl? I find no answer to these questions. I note the fact without +interpreting it: when the shell is a large one, the front part, +almost the whole of the last whorl, remains an empty vestibule. + +To the spring Resin-bee, Anthidium septemdentatum, this less than +half occupied lodging presents no drawbacks. A contemporary of the +Osmia, often her neighbour under the same stone, the gum-worker +builds her nest at the same period as the mud-worker; but there is no +fear of mutual encroachments, for the two Bees, working next door to +each other, watch their respective properties with a jealous eye. If +attempts at usurpation were to be made, the owner of the Snail-shell +would know how to enforce her rights as the first occupant. + +For the summer Resin-bee, A. bellicosum, the conditions are very +different. At the moment when the Osmia is building, she is still in +the larval, or at most in the nymphal stage. Her abode, which would +not be more absolutely silent if deserted, her shell, with its vast +untenanted porch, will not tempt the earlier Resin-bee, who herself +wants apartments right at the far end of the spiral, but it might +suit the Osmia, who knows how to fill the shell with cells up to the +mouth. The last whorl left vacant by the Anthidium is a magnificent +lodging which nothing prevents the mason from occupying. The Osmia +does seize upon it, in fact, and does so too often for the welfare of +the unfortunate late-comer. The final resin lid takes the place, for +the Osmia, of the mud stopper with which she cuts off at the back the +portion of the spiral too narrow for her labours. Upon this lid she +builds her mass of cells in so many storeys, after which she covers +the whole with a thick defensive plug. In short, the work is +conducted as though the Snail-shell contained nothing. + +When July arrives, this doubly-tenanted house becomes the scene of a +tragic conflict. Those below, on attaining the adult state, burst +their swaddling-bands, demolish their resin partitions, pass through +the gravel barricade and try to release themselves; those above, +larvae still or budding pupae, prisoners in their shells until the +following spring, completely block the way. To force a passage from +the far-end of those catacombs is beyond the strength of the Resin- +bee, already weakened by the effort of breaking out of her own nest. +A few of the Osmia's partitions are damaged, a few cocoons receive +slight injuries; and then, worn out with vain struggles, the captives +abandon hope and perish behind the impregnable wall of earth. And +with them perish also certain parasites, even less fit for the +prodigious work of clearance: Zonites and Chryses (Chrysis flammea), +of whom the first are consumers of provisions and the second of +grubs. + +This lamentable ending of the Resin-bee, buried alive under the +Osmia's walls, is not a rare accident to be passed over in silence or +mentioned in a few words; on the contrary, it happens very often; and +its frequency suggests this thought: the school which sees in +instinct an acquired habit treats the slightest favourable occurrence +in the course of animal industry as the starting-point of an +improvement which, transmitted by heredity and becoming in time more +and more accentuated, at last grows into a settled characteristic +common to the whole race. There is, it is true, a total absence of +positive proofs in support of this theory; but it is stated with a +wealth of hypothesis that leaves a thousand loopholes: 'Granting +that...Supposing that...It may be...nothing need prevent us from +believing... It is quite possible...' Thus argued the master; and the +disciples have not yet hit upon anything better. + +'If the sky were to fall,' said Rabelais, 'the larks would all be +caught.' + +Yes, but the sky stays up; and the larks go on flying. + +'If things happened in such and such a way,' says our friend, +'instinct may have undergone variations and modifications.' + +Yes, but are you quite sure that things happened as you say? + +I banish the word 'if' from my vocabulary. I suppose nothing, I take +nothing for granted; I pluck the brutal fact, the only thing that can +be trusted; I record it and then ask myself what conclusion rests +upon its solid framework. From the fact which I have related we may +draw the following inference: + +'You say that any modification profitable to the animal is +transmitted throughout a series of favoured ones who, better equipped +with tools, better endowed with aptitudes, abandon the ancient usages +and replace the primitive species, the victim of the struggle for +life. You declare that once, in the dim distance of the ages, a Bee +found herself by accident in possession of a dead Snail-shell. The +safe and peaceful lodging pleased her fancy. On and on went the +hereditary liking; and the Snail-shell proved more and more agreeable +to the insect's descendants, who began to look for it under the +stones, so that later generations, with the aid of habit, ended by +adopting it as the ancestral dwelling. Again by accident, the Bee +happened upon a drop of resin. It was soft, plastic, well-suited for +the partitioning of the Snail-shell; it soon hardened into a solid +ceiling. The Bee tried the resinous gum and benefited by it. Her +successors also benefited by it, especially after improving it. +Little by little, the rubble-work of the lid and of the gravel +barricade was invented: an enormous improvement, of which the race +did not fail to take advantage. The defensive fortification was the +finishing-touch to the original structure. Here we have the origin +and development of the instinct of the Resin-bees who make their home +in Snail-shells.' + +This glorious genesis of insect ways and means lacks just one little +thing: probability. Life everywhere, even among the humble, has two +phases: its share of good and its share of evil. Avoiding the latter +and seeking the former is the rough balance-sheet of life's actions. +Animals, like ourselves, have their portion of the sweet and the +bitter: they are just as anxious to reduce the second as to increase +the first; for, with them as with us, + +De malheurs evites le bonheur se compose. +(Bad luck missed is good luck gained.) + +If the Bee has so faithfully handed down her casual invention of a +resin nest built inside a Snail-shell, then there is no denying that +she must have just as faithfully handed down the means of averting +the terrible danger of belated hatchings. A few mothers, escaping at +rare intervals from the catacombs blocked by the Osmiae, must have +retained a lively memory, a powerful impression of their desperate +struggle through the mass of earth; they must have inspired their +descendants with a dread of those vast dwellings where the stranger +comes afterwards and builds; they must have taught them by habit the +means of safety, the use of the medium-sized shell, which the nest +fills to the mouth. So far as the prosperity of the race was +concerned, the discontinuance of the system of empty vestibules was +far more important than the invention of the barricade, which is not +altogether indispensable: it would have saved them from perishing +miserably, behind impenetrable walls, and would have considerably +increased the numbers of their posterity. + +Thousands and thousands of experiments have been made throughout the +ages with Snail-shells of average dimensions: the thing is certain, +because I find many of them to-day. Well, have these life-saving +experiments, with their immense importance to the race, become +general by hereditary bequest? Not at all: the Resin-bee persists in +using big Snail-shells just as though her ancestors had never known +the danger of the Osmia-blocked vestibule. Once these facts are duly +recognized, the conclusion is irresistible: it is obvious that, as +the insect does not hand down the casual modification tending towards +the avoidance of what is to its disadvantage, neither does it hand +down the modification leading to the adoption of what is to its +advantage. However lively the impression made upon the mother, the +accidental leaves no trace in the offspring. Chance plays no part in +the genesis of the instincts. + +Next to these tenants of the Snail-shells we have two other Resin- +bees who never come to the shells for a cabin for their nests. They +are Anthidium quadrilobum, LEP., and A. Latreillii, LEP., both +exceedingly uncommon in my district. If we meet them very rarely, +however, this may well be due to the difficulty of seeing them; for +they lead extremely solitary and wary lives. A warm nook under some +stone or other; the deserted streets of an Ant-hill in a sun-baked +bank; a Beetle's vacant burrow a few inches below the ground; in +short, a cavity of some sort, perhaps arranged by the Bee's own care: +these are the only establishments which I know them to occupy. And +here, with no other shelter than the cover of the refuge, they build +a mass of cells joined together and grouped into a sphere, which, in +the case of the Four-lobed Resin-bee, attains the size of a man's +fist and, in that of Latreille's Resin-bee, the size of a small +apple. + +At first sight, we remain very uncertain as to the nature of the +strange ball. It is brown, rather hard, slightly sticky, with a +bituminous smell. Outside are encrusted a few bits of gravel, +particles of earth, heads of large-sized Ants. This cannibal trophy +is not a sign of barbarous customs: the Bee does not decapitate Ants +to adorn her hut. An inlayer, like her colleagues of the Snail-shell, +she gathers any hard granule near at hand capable of strengthening +her work; and the dried skulls of Ants, which are frequent around +about her abode, are in her eyes building-stones of equal value to +the pebbles. One and all employ whatever they can find without much +seeking. The inhabitant of the shell, in order to construct her +barricade, makes shift with the dry excrement of the nearest Snail; +the denizen of the flat stones and of the roadside banks frequented +by the Ants does what she can with the heads of the defunct and, +should these be lacking, is ready to replace them with something +else. Moreover, the defensive inlaying is slight; we see that the +insect attaches no great importance to it and has every confidence in +the stout wall of the home. + +The material of which the work is made at first suggests some rustic +wax, much coarser than that of the Bumble-bees, or rather some tar of +unknown origin. We think again and then recognize in the puzzling +substance the semitransparent fracture, the quality of becoming soft +when exposed to heat and of burning with a smoky flame, the +solubility in spirits of wine--in short, all the distinguishing +characteristics of resin. Here then are two more collectors of the +exudations of the Coniferae. At the points where I find their nests +are Aleppo pines, cypresses, brown-berried junipers and common +junipers. Which of the four supplies the mastic? There is nothing to +tell us. Nor is there anything to explain how the native amber-colour +of the resin is replaced in the work of both Bees by a dark-brown hue +resembling that of pitch. Does the insect collect resin impaired by +the weather, soiled by the sanies of rotten wood? When kneading it, +does it mix some dark ingredient with it? I look upon this as +possible, but not as proved, since I have never seen the Bee +collecting her resin. + +While this point escapes me, another of higher interest appears most +plainly; and that is the large amount of resinous material used in a +single nest, especially in that of Anthidium quadrilobum, in which I +have counted as many as twelve cells. The nest of the Mason-bee of +the Pebbles is hardly more massive. For so costly an establishment, +therefore, the Resin-bee collects her pitch on the dead pine as +copiously as the Mason-bee collects her mortar on the macadamized +road. Her workshop no longer shows us the niggardly partitioning of a +Snail-shell with two or three drops of resin; what we see is the +whole building of the house, from the basement to the roof, from the +thick outer walls to the partitions of the rooms. The cement expended +would be enough to divide hundreds of Snail-shells, wherefore the +title of Resin-bee is due first and foremost to this master-builder +in pitch. Honourable mention should be awarded to A. Latreillii, who +rivals her fellow-worker as far as her smaller stature permits. The +other manipulators of resin, those who build partitions in Snail- +shells, come third, a very long way behind. + +And now, with the facts to support us, let us philosophize a little. +We have here, recognized as of excellent standard by all the expert +classifiers, so fastidious in the arrangement of their lists, a +generic group, called Anthidium, containing two guilds of workers +entirely dissimilar in character: the cotton-fullers and the resin- +kneaders. It is even possible that other species, when their habits +are better known, will come and increase this variety of +manufactures. I confine myself to the little that I know and ask +myself in what the manipulator of cotton differs from the manipulator +of resin as regards tools, that is to say, organs. Certainly, when +the genus Anthidium was set down by the classifiers, they were not +wanting in scientific precision: they consulted, under the lens of +the microscope, the wings, the mandibles, the legs, the harvesting- +brush, in short, all the details calculated to assist the proper +delimitation of the group. After this minute examination by the +experts, if no organic differences stand revealed, the reason is that +they do not exist. Any dissimilarity of structure could not escape +the accurate eyes of our learned taxonomists. The genus, therefore, +is indeed organically homogeneous; but industrially it is thoroughly +heterogeneous. The implements are the same and the work is different. + +That eminent Bordeaux entomologist, Professor Jean Perez, to whom I +communicated the misgivings aroused in my mind by the contradictory +nature of my discoveries, thinks that he has found the solution of +the difficulty in the conformation of the mandibles. I extract the +following passage from his volume, "Les Abeilles": + +'The cotton-pressing females have the edge of their mandibles cut out +into five or six little teeth, which make an instrument admirably +suited for scraping and removing the hairs from the epidermis of the +plants. It is a sort of comb or teasel. The resin-kneading females +have the edge of the mandible not toothed, but simply curved; the tip +alone, preceded by a notch which is pretty clearly marked in some +species, forms a real tooth; but this tooth is blunt and does not +project. The mandible, in short, is a kind of spoon perfectly fitted +to remove the sticky matter and to shape it into a ball.' + +Nothing better could be said to explain the two sorts of industry: in +the one case, a rake which gathers the wool; in the other, a spoon +which scoops up the resin. I should have left it at that and felt +quite content without further investigation, if I had not had the +curiosity to open my boxes and, in my turn, to take a good look, side +by side, at the workers in cement and the workers in cotton. Allow +me, my learned master, to whisper in your ear what I saw. + +The first that I examine is Anthidium septemdentatum. A spoon: yes, +it is just that. Powerful mandibles, shaped like an isosceles +triangle, flat above, hollowed out below; and no indentations, none +whatsoever. A splendid tool, as you say, for gathering the viscous +pellet; quite as efficacious in its kind of work as is the rake of +the toothed mandibles for gathering cotton. Here certainly is a +creature potently-gifted, even though it be for a poor little task, +the scooping up of two or three drops of glue. + +Things are not quite so satisfactory with the second Resin-bee of the +Snail-shells, A. bellicosum. I find that she has three teeth to her +mandibles. Still, they are slight and project very little. Let us say +that this does not count, even though the work is exactly the same. +With A. quadrilobum the whole thing breaks down. She, the queen of +Resin-bees; she, who collects a lump of mastic the size of one's +fist, enough to subdivide hundreds of her kinswomen's Snail-shells: +well, she, by way of a spoon, carries a rake! On the wide edges of +her mandibles stand four teeth, as long and pointed as those of the +most zealous cotton-gleaner. A. florentinum, that mighty manufacturer +of cotton-goods, can hardly rival her in respect of combing-tools. +And nevertheless, with her toothed implement, a sort of saw, the +Resin-bee collects her great heap of pitch, load by load; and the +material is carried not rigid, but sticky, half-fluid, so that it may +amalgamate with the previous lots and be fashioned into cells. + +A. Latreillii, without having a very large implement, also bears +witness to the possibility of heaping up soft resin with a rake; she +arms her mandibles with three or four sharply-cut teeth. In short, +out of four Resin-bees, the only four that I know, one is armed with +a spoon, if this expression be really suited to the tool's function; +the three others are armed with a rake; and it so happens that the +most copious heap of resin is just the work of the rake with the most +teeth to it, a tool suited to the cotton-reapers, according to the +views of the Bordeaux entomological expert. + +No, the explanation that appealed to me so much at first is not +admissible. The mandible, whether supplied with teeth or not, does +not account at all for the two manufactures. May we, in this +predicament, have recourse to the general structure of the insect, +although this is not distinctive enough to be of much use to us? Not +so either; for, in the same stone-heaps where the Osmia and the two +Resin-bees of the Snail-shells work, I find from time to time another +manipulator of mastic who bears no structural relationship whatever +to the genus Anthidium. It is a small-sized Mason-wasp, Odynerus +alpestris, SAUSS. She builds a very pretty nest with resin and gravel +in the shells of the young Common Snail, of Helix nemoralis and +sometimes of Bulimulus radiatus. I will describe her masterpiece on +some other occasion. To one acquainted with the genus Odynerus, any +comparison with the Anthidia would be an inexcusable error. In larval +diet, in shape, in habits, they form two dissimilar groups, very far +removed one from the other. The Anthidia feed their offspring on +honey-bread; the Odyneri feed it on live prey. Well, with her slender +form, her weakly frame, in which the most clear-seeing eye would seek +in vain for a clue to the trade practised, the Alpine Odynerus, the +game-lover, uses pitch in the same way as the stout and massive +Resin-bee, the honey-lover. She even uses it better, for her mosaic +of tiny pebbles is much prettier than the Bee's and no less solid. +With her mandibles, this time neither spoon nor rake, but rather a +long forceps slightly notched at the tip, she gathers her drop of +sticky matter as dexterously as do her rivals with their very +different outfit. Her case will, I think, persuade us that neither +the shape of the tool nor the shape of the worker can explain the +work done. + +I will go further: I ask myself in vain the reason of this or that +trade in the case of a fixed species. The Osmiae make their +partitions with mud or with a paste of chewed leaves; the Mason-bees +build with cement; the Pelopaeus-wasps fashion clay pots; the +Megachiles made disks cut from leaves into urns; the Anthidia felt +cotton into purses; the Resin-bees cement together little bits of +gravel with gum; the Carpenter-bees and the Lithurgi bore holes in +timber; the Anthophorae tunnel the roadside slopes. Why all these +different trades, to say nothing of the others? How are they +prescribed for the insect, this one rather than that? + +I foresee the answer: they are prescribed by the organization. An +insect excellently equipped for gathering and felting cotton is ill- +equipped for cutting leaves, kneading mud or mixing resin. The tool +in its possession decides its trade. + +This is a very simple explanation, I admit, and one within the scope +of everybody: in itself a sufficient recommendation for any one who +has neither the inclination nor the time to undertake a more thorough +investigation. The popularity of certain speculative views is due +entirely to the easy food which they provide for our curiosity. They +save us much long and often irksome study; they impart a veneer of +general knowledge. There is nothing that achieves such immediate +success as an explanation of the riddle of the universe in a word or +two. The thinker does not travel so fast: content to know little so +that he may know something, he limits his field of search and is +satisfied with a scanty harvest, provided that the grain be of good +quality. Before agreeing that the tool determines the trade, he wants +to see things with his own eyes; and what he observes is far from +confirming the sweeping statement. Let us share his doubts for a +moment and look into matters more closely. + +Franklin left us a maxim which is much to the point here. He said +that a good workman should be able to plane with a saw and to saw +with a plane. The insect is too good a workman not to follow the +advice of the sage of Boston. Its industry abounds in instances where +the plane takes the place of the saw, or the saw of the plane; its +dexterity makes good the inadequacy of the implement. To go no +further, have we not just seen different artisans collecting and +using pitch, some with spoons, others with rakes, others again with +pincers? Therefore, with such equipment as it possesses, the insect +would be capable of abandoning cotton for leaves, leaves for resin, +resin for mortar, if some predisposition of talent did not make it +keep to its speciality. + +These few lines, which are the outcome not of a heedless pen but of +mature reflection, will set people talking of hateful paradoxes. We +will let them talk and we will submit the following proposition to +our adversaries: take an entomologist of the highest merit, a +Latreille (Pierre Andre Latreille (1762-1833), one of the founders of +modern entomological science.--Translator's Note.), for instance, +versed in all the details of the structure of insects but utterly +unacquainted with their habits. He knows the dead insect better than +anybody, but he has never occupied himself with the living insect. As +a classifier, he is beyond compare; and that is all. We ask him to +examine a Bee, the first that comes to hand, and to name her trade +from her tools. + +Come, be honest: could he? Who would dare put him to such a test? Has +personal experience not fully convinced us that the mere examination +of the insect can tell us nothing about its particular industry? The +baskets on its legs and the brush on its abdomen will certainly +inform us that it collects honey and pollen; but its special art will +remain an utter secret, notwithstanding all the scrutiny of the +microscope. In our own industries, the plane denotes the joiner, the +trowel the mason, the scissors the tailor, the needle the seamstress. +Are things the same in animal industry? Just show us, if you please, +the trowel that is a certain sign of the mason-insect, the chisel +that is a positive characteristic of the carpenter-insect, the iron +that is an authentic mark of the pinking-insect; and as you show +them, say: + +'This one cuts leaves; that one bores wood; that other mixes cement.' + +And so on, specifying the trade from the tool. + +You cannot do it, no one can; the worker's speciality remains an +impenetrable secret until direct observation intervenes. Does not +this incapacity, even of the most expert, proclaim loudly that animal +industry, in its infinite variety, is due to other causes besides the +possession of tools? Certainly, each of those specialists requires +implements; but they are rough and ready implements, good for all +sorts of purposes, like the tool of Franklin's workman. The same +notched mandible that reaps cotton, cuts leaves and moulds pitch also +kneads mud, scrapes decayed wood and mixes mortar; the same tarsus +that manufactures cotton and disks cut out of leaves is no less +clever at the art of making earthen partitions, clay turrets and +gravel mosaics. + +What then is the reason of these thousand industries? In the light of +facts, I can see but one: imagination governing matter. A primordial +inspiration, a talent antecedent to the actual form, directs the tool +instead of being subordinate to it. The instrument does not determine +the manner of industry; the tool does not make the workman. At the +beginning there is an object, a plan, in view of which the animal +acts, unconsciously. Have we eyes to see with, or do we see because +we have eyes? Does the function create the organ, or the organ the +function? Of the two alternatives, the insect proclaims the first. It +says: + +'My industry is not imposed upon me by the implement which I possess; +what I do is to use the implement, such as it is, for the talent with +which I am gifted.' + +It says to us, in its own way: + +'The function has determined the organ; vision is the reason of the +eye.' + +In short, it repeats to us Virgil's profound reflection: + +'Mens agitat molem'; 'Mind moves matter.' + + +CHAPTER 11. THE POISON OF THE BEE. + +I have discussed elsewhere the stings administered by the Wasps to +their prey. Now chemistry comes and puts a spoke in the wheel of our +arguments, telling us that the poison of the Bees is not the same as +that of the Wasps. The Bees' is complex and formed of two elements, +acid and alkaline. The Wasps' possess only the acid element; and it +is to this very acidity and not to the 'so-called' skill of the +operators that the preservation of the provisions is due. (The +author's numerous essays on the Wasps will form the contents of later +works. In the meantime, cf. "Insect Life," by J.H. Fabre, translated +by the author of "Mademoiselle Mori": chapters 4 to 12, and 14 to 18; +and "The Life and Love of the Insect," by J. Henri Fabre, translated +by Alexander Teixeira de Mattos: chapters 11, 12 and 17.-- +Translator's Note.) + +Admitting that there is a difference in the nature of the venom, I +fail to see that this has any bearing on the problem in hand. I can +inoculate with various liquids--acids, weak nitric acid, alkalis, +ammonia, neutral bodies, spirits of wine, essence of turpentine--and +obtain conditions similar to those of the victims of the predatory +insects, that is to say, inertia with the persistence of a dull +vitality betrayed by the movements of the mouth-parts and antennae. I +am not, of course, invariably successful, for there is neither +delicacy nor precision in my poisoned needle and the wound which it +makes does not bear comparison with the tiny puncture of the unerring +natural sting; but, after all, it is repeated often enough to put the +object of my experiment beyond doubt. I should add that, to achieve +success, we must have a subject with a concentrated ganglionic +column, such as the Weevil, the Buprestis, the Dung-beetle and +others. Paralysis is then obtained with but a single prick, made at +the point which the Cerceris has revealed to us, the point at which +the corselet joins the rest of the thorax. In that case, the least +possible quantity of the acrid liquid is instilled, a quantity too +small to endanger the patient's life. With scattered nervous centres, +each requiring a separate operation, this method is impracticable: +the victim would die of the excess of corrosive fluid. I am quite +ashamed to have to recall these old experiments. Had they been +resumed and carried on by others of greater authority than I, we +should have escaped the objections of chemistry. + +When light is so easy to obtain, why go in search of scientific +obscurity? Why talk of acid or alkaline reactions, which prove +nothing, when it is so simple to have recourse to facts, which prove +everything? Before declaring that the hunting insects' poison has +preservative properties merely because of its acid qualities, it +would have been well to enquire if the sting of a Bee, with its acid +and its alkali, could not perchance produce the same effects as that +of the paralyser, whose skill is categorically denied. The chemists +never gave this a thought. Simplicity is not always welcome in our +laboratories. It is my duty to repair that little omission. I propose +to enquire if the poison of the Bee, the chief of the Apidae, is +suitable for a surgery that paralyses without killing. + +The enquiry bristles with difficulties, though this is no reason for +abandoning it. First and foremost, I cannot possibly operate with the +Bee just as I catch her. Time after time I make the attempt, without +once succeeding; and patience becomes exhausted. The sting has to +penetrate at a definite point, exactly where the Wasp's sting would +have entered. My intractable captive tosses about angrily and stings +at random, never where I wish. My fingers get hurt even oftener than +the patient. I have only one means of gaining a little control over +the indomitable dart; and that is to cut off the Bee's abdomen with +my scissors, to seize the stump instantly with a fine forceps and to +apply the tip at the spot where the sting is to enter. + +Everybody knows that the Bee's abdomen needs no orders from the head +to go on drawing its weapon for a few instants longer and to avenge +the deceased before being itself overcome with death's inertia. This +vindictive persistency serves me to perfection. There is another +circumstance in my favour: the barbed sting remains where it is, +which enables me to ascertain the exact spot pierced. A needle +withdrawn as soon as inserted would leave me doubtful. I can also, +when the transparency of the tissues permits, perceive the direction +of the weapon, whether perpendicular and favourable to my plans, or +slanting and therefore valueless. Those are the advantages. + +The disadvantages are these: the amputated abdomen, though more +tractable than the entire Bee, is still far from satisfying my +wishes. It gives capricious starts and unexpected pricks. I want it +to sting here. No, it balks my forceps and goes and stings elsewhere: +not very far away, I admit; but it takes so little to miss the nerve- +centre which we wish to get at. I want it to go in perpendicularly. +No, in the great majority of cases it enters obliquely and passes +only through the epidermis. This is enough to show how many failures +are needed to make one success. + +Nor is this all. I shall be telling nobody anything new when I recall +the fact that the Bee's sting is very painful. That of the hunting +insects, on the contrary, is in most cases insignificant. My skin, +which is no less sensitive than another's, pays no attention to it: I +handle Sphex, Ammophilae and Scoliae without heeding their lancet- +pricks. I have said this before; I remind the reader of it because of +the matter in hand. In the absence of well-known chemical or other +properties, we have really but one means of comparing the two +respective poisons; and that is the amount of pain produced. All the +rest is mystery. Besides, no poison, not even that of the +Rattlesnake, has hitherto revealed the cause of its dread effects. + +Acting, therefore, under the instruction of that one guide, pain, I +place the Bee's sting far above that of the predatory insects as an +offensive weapon. A single one of its thrusts must equal and often +surpass in efficaciousness the repeated wounds of the other. For all +these reasons--an excessive display of energy; the variable quantity +of the virus inoculated by a wriggling abdomen which no longer +measures the emission by doses; a sting which I cannot direct as I +please; a wound which may be deep or superficial, the weapon entering +perpendicularly or obliquely, touching the nerve-centres or affecting +only the surrounding tissues--my experiments ought to produce the +most varied results. + +I obtain, in fact, every possible kind of disorder: ataxy, temporary +disablement, permanent disablement, complete paralysis, partial +paralysis. Some of my stricken victims recover; others die after a +brief interval. It would be an unnecessary waste of space to record +in this volume my hundred and one attempts. The details would form +tedious reading and be of very little advantage, as in this sort of +study it is impossible to marshal one's facts with any regularity. I +will, therefore, sum them up in a few examples. + +A colossal member of the Grasshopper tribe, the most powerful in my +district, Decticus verrucivorus (This Decticus has received its +specific name of verrucivorus, or Wart-eating, because it is employed +by the peasants in Sweden and elsewhere to bite off the warts on +their fingers.--Translator's Note.), is pricked at the base of the +neck, on the line of the fore-legs, at the median point. The prick +goes straight down. The spot is the same as that pierced by the sting +of the slayer of Crickets and Ephippigers. (A species of Green +Grasshopper. The Sphex paralyses Crickets and Grasshoppers to provide +food for her grubs. Cf. "Insect Life": chapters 6 to 12.-- +Translator's Note.) The giantess, as soon as stung, kicks furiously, +flounders about, falls on her side and is unable to get up again. The +fore-legs are paralysed; the others are capable of moving. Lying +sideways, if not interfered with, the insect in a few moments gives +no signs of life beyond a fluttering of the antennae and palpi, a +pulsation of the abdomen and a convulsive uplifting of the +ovipositor; but, if irritated with a slight touch, it stirs its four +hind-legs, especially the third pair, those with the big thighs, +which kick vigorously. Next day, the condition is much the same, with +an aggravation of the paralysis, which has now attacked the middle- +legs. On the day after that, the legs do not move, but the antennae, +the palpi and the ovipositor continue to flutter actively. This is +the condition of the Ephippiger stabbed three times in the thorax by +the Languedocian Sphex. One point alone is missing, a most important +point: the long persistence of a remnant of life. In fact, on the +fourth day, the Decticus is dead; her dark colour tells me so. + +There are two conclusions to be drawn from this experiment and it is +well to emphasise them. First, the Bee's poison is so active that a +single dagger-thrust aimed at a nervous centre kills in four days one +of the largest of the Orthoptera (An order of insects including the +Grasshoppers, Locusts, Cockroaches, Mantes and Earwigs, in addition +to the Stick- and Leaf-insects, Termites, Dragon-flies, May-flies, +Book-lice and others.--Translator's Note.), though an insect of +powerful constitution. Secondly, the paralysis at first affects only +the legs whose ganglion is attacked; next, it spreads slowly to the +second pair; lastly, it reaches the third. The local effect is +diffused. This diffusion, which might well take place in the victims +of the predatory insects, plays no part in the latters' method of +operation. The egg, which will be laid immediately afterwards, +demands the complete inertia of the prey from the outset. Hence all +the nerve-centres that govern locomotion must be numbed +instantaneously by the virus. + +I can now understand why the poison of the predatory Wasps is +comparatively painless in its effects. If it possessed the strength +of that of the Bee, a single stab would impair the vitality of the +prey, while leaving it for some days capable of violent movements +that would be very dangerous to the huntress and especially to the +egg. More moderate in its action, it is instilled at the different +nervous centres, as is the case more particularly with the +caterpillars. (Caterpillars are the prey of the Ammophila, which +administers a separate stab to each of the several ganglia.-- +Translator's Note.) In this way, the requisite immobility is obtained +at once; and, notwithstanding the number of wounds, the victim is not +a speedy corpse. To the marvels of the paralysers' talent we must add +one more: their wonderful poison, the strength of which is regulated +by delicate doses. The Bee revenging herself intensifies the +virulence of her poison; the Sphex putting her grubs' provender to +sleep weakens it, reduces it to what is strictly necessary. + +One more instance of nearly the same kind. I prefer to take my +subjects from among the Orthoptera, which, owing to their imposing +size and the thinness of their skin at the points to be attacked, +lend themselves better than other insects to my delicate +manipulations. The armour of a Buprestis, the fat blubber of a +Rosechafer-grub, the contortions of a caterpillar present almost +insuperable obstacles to the success of a sting which it is not in my +power to direct. The insect which I now offer to the Bee's lancet is +the Great Green Grasshopper (Locusta viridissima), the adult female. +The prick is given in the median line of the fore-legs. + +The effect is overwhelming. For two or three seconds the insect +writhes in convulsions and then falls on its side, motionless +throughout, save in the ovipositor and the antennae. Nothing stirs so +long as the creature is left alone; but, if I tickle it with a hair- +pencil, the four hind-legs move sharply and grip the point. As for +the fore-legs, smitten in their nerve-centre, they are quite +lifeless. The same condition is maintained for three days longer. On +the fifth day, the creeping paralysis leaves nothing free but the +antennae waving to and fro and the abdomen throbbing and lifting up +the ovipositor. On the sixth, the Grasshopper begins to turn brown; +she is dead. Except that the vestige of life is more persistent, the +case is the same as that of the Decticus. If we can prolong the +duration, we shall have the victim of the Sphex. + +But first let us look into the effect of a prick administered +elsewhere than opposite the thoracic ganglia. I cause a female +Ephippiger to be stung in the abdomen, about the middle of the lower +surface. The patient does not seem to trouble greatly about her +wound: she clambers gallantly up the sides of the bell-jar under +which I have placed her; she goes on hopping as before. Better still, +she sets about browsing the vine-leaf which I have given her for her +consolation. A few hours pass and the whole thing is forgotten. She +has made a rapid and complete recovery. + +A second is wounded in three places on the abdomen: in the middle and +on either side. On the first day, the insect seems to have felt +nothing; I see no sign of stiffness in its movements. No doubt it is +suffering acutely; but these stoics keep their troubles to +themselves. Next day, the Ephippiger drags her legs a little and +walks somewhat slowly. Two days more; and, when laid on her back, she +is unable to turn over. On the fifth day, she succumbs. This time, I +have exceeded the dose; the shock of receiving three stabs was too +much for her. + +And so with the others, down to the sensitive Cricket, who, pricked +once in the abdomen, recovers in one day from the painful experience +and goes back to her lettuce-leaf. But, if the wound is repeated a +few times, death ensues within a more or less short period. I make an +exception, among those who pay tribute to my cruel curiosity, of the +Rosechafer-grubs, who defy three and four needle-thrusts. They will +collapse suddenly and lie outstretched, flabby and lifeless; and, +just when I am thinking them dead or paralysed, the hardy creatures +will recover consciousness, move along on their backs (This is the +usual mode of progression of the Cetonia- or Rosechafer-grub. Cf. +"The Life and Love of the Insect": chapter 11.--Translator's Note.), +bury themselves in the mould. I can obtain no precise information +from them. True, their thinly scattered cilia and their breastplate +of fat form a palisade and a rampart against the sting, which nearly +always enters only a little way and that obliquely. + +Let us leave these unmanageable ones and keep to the Orthoperon, +which is more amenable to experiment. A dagger-thrust, we were +saying, kills it if directed upon the ganglia of the thorax; it +throws it into a transient state of discomfort if directed upon +another point. It is, therefore, by its direct action upon the +nervous centres that the poison reveals its formidable properties. + +To generalize and say that death is always near at hand when the +sting is administered in the thoracic ganglia would be going too far: +it occurs frequently, but there are a good many exceptions, resulting +from circumstances impossible to define. I cannot control the +direction of the sting, the depth attained, the quantity of poison +shed; and the stump of the Bee is very far from making up for my +shortcomings. We have here not the cunning sword-play of the +predatory insect, but a casual blow, ill-placed and ill-regulated. +Any accident is possible, therefore, from the gravest to the mildest. +Let us mention some of the more interesting. + +An adult Praying Mantis (Mantis religiosa, so-called because the +toothed fore-legs, in which it catches and kills its prey, adopt, +when folded, an attitude resembling that of prayer.--Translator's +Note.) is pricked level with the attachment of the predatory legs. +Had the wound been in the centre, I should have witnessed an +occurrence which, although I have seen it many times, still arouses +my liveliest emotion and surprise. This is the sudden paralysis of +the warrior's savage harpoons. No machinery stops more abruptly when +the mainspring breaks. As a rule, the inertia of the predatory legs +attacks the others in the course of a day or two; and the palsied one +dies in less than a week. But the present sting is not in the exact +centre. The dart has entered near the base of the right leg, at less +than a millimetre (.039 inch.--Translator's Note.) from the median +point. That leg is paralysed at once; the other is not; and the +insect employs it to the detriment of my unsuspecting fingers, which +are pricked to bleeding-point by the spike at the tip. Not until to- +morrow is the leg which wounded me to-day rendered motionless. This +time, the paralysis goes no farther. The Mantis moves along quite +well, with her corselet proudly raised, in her usual attitude; but +the predatory fore-arms, instead of being folded against the chest, +ready for attack, hang lifeless and open. I keep the cripple for +twelve days longer, during which she refuses all nourishment, being +incapable of using her tongs to seize the prey and lift it to her +mouth. The prolonged abstinence kills her. + +Some suffer from locomotor ataxy. My notes recall an Ephippiger who, +pricked in the prothorax away from the median line, retained the use +of her six limbs without being able to walk or climb for lack of co- +ordination in her movements. A singular awkwardness left her wavering +between going back and going forward, between turning to the right +and turning to the left. + +Some are smitten with semiparalysis. A Cetonia-grub, pricked away +from the centre on a level with the fore-legs, has her right side +flaccid, spread out, incapable of contracting, while the left side +swells, wrinkles and contracts. Since the left half no longer +receives the symmetrical cooperation of the right half, the grub, +instead of curling into the normal volute, closes its spiral on one +side and leaves it wide open on the other. The concentration of the +nervous apparatus, poisoned by the venom down one side of the body +only, a longitudinal half, explains this condition, which is the most +remarkable of all. + +There is nothing to be gained by multiplying these examples. We have +seen pretty clearly the great variety of results produced by the +haphazard sting of a Bee's abdomen; let us now come to the crux of +the matter. Can the Bee's poison reduce the prey to the condition +required by the predatory Wasp? Yes, I have proved it by experiment; +but the proof calls for so much patience that it seemed to me to +suffice when obtained once for each species. In such difficult +conditions, with a poison of excessive strength, a single success is +conclusive proof; the thing is possible so long as it occurs once. + +A female Ephippiger is stung at the median point, just a little in +front of the fore-legs. Convulsive movements lasting for a few +seconds are followed by a fall to one side, with pulsations of the +abdomen, flutterings of the antennae and a few feeble movements of +the legs. The tarsi cling firmly to the hair-pencil which I hold out +to them. I place the insect on its back. It lies motionless. Its +state is absolutely the same as that to which the Languedocian Sphex +(Cf. "Insect Life": chapter 10.--Translator's Note.) reduces her +Ephippigers. For three weeks on end, I see repeated in all its +details the spectacle to which I have been accustomed in the victims +extracted from the burrows or taken from the huntress: the wide-open +mandibles, the quivering palpi and tarsi, the ovipositor shuddering +convulsively, the abdomen throbbing at long intervals, the spark of +life rekindled at the touch of a pencil. In the fourth week, these +signs of life, which have gradually weakened, disappear, but the +insect still remains irreproachably fresh. At last a month passes; +and the paralysed creature begins to turn brown. It is over; death +has come. + +I have the same success with a Cricket and also with a Praying +Mantis. In all three cases, from the point of view of long-maintained +freshness and of the signs of life proved by slight movements, the +resemblance between my victim and those of the predatory insects is +so great that no Sphex and no Tachytes would have disowned the +product of my devices. My Cricket, my Ephippiger, my Mantis had the +same freshness as theirs; they preserved it as theirs did for a +period amply sufficient to allow of the grubs' complete evolution. +They proved to me, in the most conclusive manner, they prove to all +whom it may interest, that the poison of the Bees, leaving its +hideous violence on one side, does not differ in its effects from the +poison of the predatory Wasps. Are they alkaline or acid? The +question is an idle one in this connection. Both of them intoxicate, +derange, torpify the nervous centres and thus produce either death or +paralysis, according to the method of inoculation. For the moment, +that is all. No one is yet able to say the last word on the actions +of those poisons, so terrible in infinitesimal doses. But on the +point under discussion we need no longer be ignorant: the Wasp owes +the preservation of her grub's provisions not to any special +qualities of her poison but to the extreme precision of her surgery. + +A last and more plausible objection is that raised by Darwin when he +said that there were no fossil remains of instincts. And, if there +were, O master, what would they teach us? Not very much more than +what we learn from the instincts of to-day. Does not the geologist +make the erstwhile carcases live anew in our minds in the light of +the world as we see it? With nothing but analogy to guide them, he +describes how some saurian lived in the jurassic age; there are no +fossil remains of habits, but nevertheless he can tell us plenty +about them, things worthy of credence, because the present teaches +him the past. Let us do a little as he does. + +I will suppose a precursor of the Calicurgi (The Calicurgus, or +Pompilus, is a Hunting Wasp, feeding her larvae on Spiders. Cf. "The +Life and Love of the Insect": chapter 12.--Translator's Note.) +dwelling in the prehistoric coal-forests. Her prey was some hideous +Scorpion, that first-born of the Arachnida. How did the Hymenopteron +master the terrible prey? Analogy tells us, by the methods of the +present slayer of Tarantulae. It disarmed the adversary; it paralysed +the venomous sting by a stroke administered at a point which we could +determine for certain by the animal's anatomy. Unless this was the +way it happened, the assailant must have perished, first stabbed and +then devoured by the prey. There is no getting away from it: either +the precursor of the Calicurgi, that slaughterer of Scorpions, knew +her trade thoroughly, or else the continuation of her race became +impossible, even as it would be impossible to keep up the race of the +Tarantula-killer without the dagger-thrust that paralyses the +Spider's poison-fangs. The first who, greatly daring, pinked the +Scorpion of the coal-seams was already an expert fencer; the first to +come to grips with the Tarantula had an unerring knowledge of her +dangerous surgery. The least hesitation, the slightest speculation; +and they were lost. The first teacher would also have been the last, +with no disciples to take up her work and perfect it. + +But fossil instincts, they insist, would show us intermediary stages, +first, second and third rungs; they would show us the gradual passing +from the casual and very incorrect attempt to the perfect practice, +the fruit of the ages; with their accidental differences, they would +give us terms of comparison wherewith to trace matters from the +simple to the complex. Never mind about that, my masters: if you want +varied instincts in which to seek the source of the complex by means +of the simple, it is not necessary to search the foliations of the +coal-seams and the successive layers of the rocks, those archives of +the prehistoric world; the present day affords to contemplation an +inexhaustible treasury realizing perhaps everything that can emerge +from the limbo of possibility. In what will soon be half a century of +study, I have caught but a tiny glimpse of a very tiny corner of the +realm of instinct; and the harvest gathered overwhelms me with its +variety: I do not yet know two species of predatory Wasps whose +methods are exactly the same. + +One gives a single stroke of the dagger, a second two, a third three, +a fourth nine or ten. One stabs here and the other there; and neither +is imitated by the next, who attacks elsewhere. This one injures the +cephalic centres and produces death; that one respects them and +produces paralysis. Some squeeze the cervical ganglia to obtain a +temporary torpor; others know nothing of the effects of compressing +the brain. A few make the prey disgorge, lest its honey should poison +the offspring; the majority do not resort to preventive +manipulations. Here are some that first disarm the foe, who carries +poisoned daggers; yonder are others and more numerous, who have no +precautions to take before murdering the unarmed prey. In the +preliminary struggle, I know some who grab their victims by the neck, +by the rostrum, by the antennae, by the caudal threads; I know some +who throw them on their backs, some who lift them breast to breast, +some who operate on them in the vertical position, some who attack +them lengthwise and crosswise, some who climb on their backs or on +their abdomens, some who press on their backs to force out a pectoral +fissure, some who open their desperately contracted coil, using the +tip of the abdomen as a wedge. And so I could go on indefinitely: +every method of fencing is employed. What could I not also say about +the egg, slung pendulum-fashion by a thread from the ceiling, when +the live provisions are wriggling underneath; laid on a scanty +mouthful, a solitary opening dish, when the dead prey requires +renewing from day to-day; entrusted to the last joint stored away, +when the victuals are paralysed; fixed at a precise spot, entailing +the least danger to the consumer and the game, when the corpulent +prey has to be devoured with a special art that warrants its +freshness! + +Well, how can this multitude of varied instincts teach us anything +about gradual transformation? Will the one and only dagger-thrust of +the Cerceris and the Scolia take us to the two thrusts of the +Calicurgus, to the three thrusts of the Sphex, to the manifold thrust +of the Ammophila? Yes, if we consider only numerical progression. One +and one are two; two and one are three: so run the figures. But is +this what we want to know? What has arithmetic to do with the case? +Is not the whole problem subordinate to a condition that cannot be +translated into cyphers? As the prey changes, the anatomy changes; +and the surgeon always operates with a complete understanding of his +subject. The single dagger-thrust is administered to ganglia +collected into a common cluster; the manifold thrusts are distributed +over the scattered ganglia; of the two thrusts of the Tarantula- +huntress, one disarms and the other paralyses. And so with the +others: that is to say, the instinct is directed each time by the +secrets of the nervous organism. There is a perfect harmony between +the operation and the patient's anatomy. + +The single stroke of the Scolia is no less wonderful than the +repeated strokes of the Ammophila. Each has her appointed game and +each slays it by a method as rational as any that our own science +could invent. In the presence of this consummate knowledge, which +leaves us utterly confounded, what a poor argument is that of 1 + 1 = +2! And what is that progress by units to us? The universe is mirrored +in a drop of water; universal logic flashes into sight in a single +sting. + +Besides, push on the pitiful argument. One leads to two, two lead to +three. Granted without dispute. And then? We will accept the Scolia +as the pioneer, the foundress of the first principles of the art. +The simplicity of her method justifies our supposition. She learns +her trade in some way or other, by accident; she knows supremely well +how to paralyse her Cetonia-grub with a single dagger-thrust driven +into the thorax. One day, through some fortuitous circumstance, or +rather by mistake, she takes it into her head to strike two blows. As +one is enough for the Cetonia, the repetition was of no value unless +there was a change of prey. What was the new victim submitted to the +butcher's knife? Apparently, a large Spider, since the Tarantula and +the Garden Spider call for two thrusts. And the prentice Scolia, who +used at first to sting under the throat, had the skill, at her first +attempt, to begin by disarming her adversary and then to go quite low +down, almost to the end of the thorax, to strike the vital point. I +am utterly incredulous as to her success. I see her eaten up if her +lancet swerves and hits the wrong spot. Let us look impossibility +boldly in the face and admit that she succeeds. I then see the +offspring, which have no recollection of the fortunate event save +through the belly--and then we are postulating that the digestion of +the carnivorous larva leaves a trace in the memory of the honey- +sipping insect--I see the offspring, I say, obliged to wait at long +intervals for that inspired double thrust and obliged to succeed each +time under pain of death for them and their descendants. To accept +this host of impossibilities exceeds all my faculties of belief. One +leads to two, no doubt; the Ssingle blow of the predatory Wasp will +never lead to the blow twice delivered. + +In order to live, we all require the conditions that enable us to +live: this is a truth worthy of the famous axioms of La Palice. +(Jacques de Chabannes, Seigneur de La Palice (circa 1470-1525), was a +French captain killed at the battle of Pavia. His soldiers made up in +his honour a ballad, two lines of which, translated, run: + +Fifteen minutes before he died, +He was still alive. + +Hence the French expression, une verite de La Palice, meaning an +obvious truth.--Translator's Note.) + +The predatory insects live by their talent. If they do not possess +it to perfection, their race is lost. Hidden in the murk of the past +ages, the argument based upon the non-existence of fossil instinct is +no better able than the others to withstand the light of living +realities; it crumbles under the stroke of fate; it vanishes before a +La Palice platitude. + + +CHAPTER 12. THE HALICTI: A PARASITE. + +Do you know the Halicti? Perhaps not. There is no great harm done: it +is quite possible to enjoy the few sweets of existence without +knowing the Halicti. Nevertheless, when questioned persistently, +these humble creatures with no history can tell us some very singular +things; and their acquaintance is not to be disdained if we would +enlarge our ideas upon the bewildering swarm of this world. Since we +have nothing better to do, let us look into the Halicti. They are +worth the trouble. + +How shall we recognize them? They are manufacturers of honey, +generally longer and slighter than the Bee of our hives. They +constitute a numerous group that varies greatly in size and +colouring. Some there are that exceed the dimensions of the Common +Wasp; others might be compared with the House-fly, or are even +smaller. In the midst of this variety, which is the despair of the +novice, one characteristic remains invariable. Every Halictus carries +the clearly-written certificate of her guild. + +Examine the last ring, at the tip of the abdomen, on the dorsal +surface. If your capture be an Halictus, there will be here a smooth +and shiny line, a narrow groove along which the sting slides up and +down when the insect is on the defensive. This slide for the +unsheathed weapon denotes some member of the Halictus tribe, without +distinction of size or colour. No elsewhere, in the sting-bearing +order, is this original sort of groove in use. It is the distinctive +mark, the emblem of the family. + +Three Halicti will appear before you in this biographical fragment. +Two of them are my neighbours, my familiars, who rarely fail to +settle each year in the best parts of the enclosure. They occupied +the ground before I did; and I should not dream of evicting them, +persuaded as I am that they will well repay my indulgence. Their +proximity, which allows me to visit them daily at my leisure, is a +piece of good luck. Let us profit by it. + +At the head of my three subjects is the Zebra Halictus (H. zebrus, +WALCK.), which is beautifully belted around her long abdomen with +alternate black and pale-russet scarves. Her slender shape, her size, +which equals that of the Common Wasp, her simple and pretty dress, +combine to make her the chief representative of the genus here. + +She establishes her galleries in firm soil, where there is no danger +of landslips which would interfere with the work at nesting-time. In +my garden, the well-levelled paths, made of a mixture of tiny pebbles +and red clayey earth, suits her to perfection. Every spring she takes +possession of it, never alone, but in gangs whose number varies +greatly, amounting sometimes to as many as a hundred. In this way she +founds what may be described as small townships, each clearly marked +out and distant from the other, in which the joint possession of the +site in no way entails joint work. + +Each has her home, an inviolable manor which none but the owner has +the right to enter. A sound buffeting would soon call to order any +adventuress who dared to make her way into another's dwelling. No +such indiscretion is suffered among the Halicti. Let each keep to her +own place and to herself and perfect peace will reign in this new- +formed society, made up of neighbours and not of fellow-workers. + +Operations begin in April, most unobtrusively, the only sign of the +underground works being the little mounds of fresh earth. There is no +animation in the building-yards. The labourers show themselves very +seldom, so busy are they at the bottom of their pits. At moments, +here and there, the summit of a tiny mole-hill begins to totter and +tumbles down the slopes of the cone: it is a worker coming up with +her armful of rubbish and shooting it outside, without showing +herself in the open. Nothing more for the moment. + +There is one precaution to be taken: the villages must be protected +against the passers-by, who might inadvertently trample them under +foot. I surround each of them with a palisade of reed-stumps. In the +centre I plant a danger-signal, a post with a paper flag. The +sections of the paths thus marked are forbidden ground; none of the +household will walk upon them. + +May arrives, gay with flowers and sunshine. The navvies of April have +turned themselves into harvesters. At every moment I see them +settling, all befloured with yellow, atop of the mole-hills now +turned into craters. Let us first look into the question of the +house. The arrangement of the home will give us some useful +information. A spade and a three-pronged fork place the insect's +crypts before our eyes. + +A shaft as nearly vertical as possible, straight or winding according +to the exigencies of a soil rich in flinty remains, descends to a +depth of between eight and twelve inches. As it is merely a passage +in which the only thing necessary is that the Halictus should find an +easy support in coming and going, this long entrance-hall is rough +and uneven. A regular shape and a polished surface would be out of +place here. These artistic refinements are reserved for the +apartments of her young. All that the Halictus mother asks is that +the passage should be easy to go up and down, to ascend or descend in +a hurry. And so she leaves it rugged. Its width is about that of a +thick lead-pencil. + +Arranged one by one, horizontally and at different heights, the cells +occupy the basement of the house. They are oval cavities, three- +quarters of an inch long, dug out of the clay mass. They end in a +short bottle-neck that widens into a graceful mouth. They look like +tiny vaccine-phials laid on their sides. All of them open into the +passage. + +The inside of these little cells has the gloss and polish of a stucco +which our most experienced plasterers might envy. It is diapered with +faint longitudinal, diamond-shaped marks. These are the traces of the +polishing-tool that has given the last finish to the work. What can +this polisher be? None other than the tongue, that is obvious. The +Halictus has made a trowel of her tongue and licked the wall daintily +and methodically in order to polish it. + +This final glazing, so exquisite in its perfection, is preceded by a +trimming-process. In the cells that are not yet stocked with +provisions, the walls are dotted with tiny dents like those in a +thimble. Here we recognize the work of the mandibles, which squeeze +the clay with their tips, compress it and purge it of any grains of +sand. The result is a milled surface whereon the polished layer will +find a solid adhesive base. This layer is obtained with a fine clay, +very carefully selected by the insect, purified, softened and then +applied atom by atom, after which the trowel of the tongue steps in, +diapering and polishing, while saliva, disgorged as needed, gives +pliancy to the paste and finally dries into a waterproof varnish. + +The humidity of the subsoil, at the time of the spring showers, would +reduce the little earthen alcove to a sort of pap. The coating of +saliva is an excellent preservative against this danger. It is so +delicate that we suspect rather than see it; but its efficacy is none +the less evident. I fill a cell with water. The liquid remains in it +quite well, without any trace of infiltration. + +The tiny pitcher looks as if it were varnished with galenite. The +impermeability which the potter obtains by the brutal infusion of his +mineral ingredients the Halictus achieves with the soft polisher of +her tongue moistened with saliva. Thus protected, the larva will +enjoy all the advantages of a dry berth, even in rain-soaked ground. + +Should the wish seize us, it is easy to detach the waterproof film, +at least in shreds. Take the little shapeless lump in which a cell +has been excavated and put it in sufficient water to cover the bottom +of it. The whole earthy mass will soon be soaked and reduced to a mud +which we are able to sweep with the point of a hair-pencil. Let us +have patience and do our sweeping gently; and we shall be able to +separate from the main body the fragments of a sort of extremely fine +satin. This transparent, colourless material is the upholstery that +keeps out the wet. The Spider's web, if it formed a stuff and not a +net, is the only thing that could be compared with it. + +The Halictus' nurseries are, as we see, structures that take much +time in the making. The insect first digs in the clayey earth a +recess with an oval curve to it. It has its mandibles for a pick-axe +and its tarsi, armed with tiny claws, for rakes. Rough though it be, +this early work presents difficulties, for the Bee has to do her +excavating in a narrow gully, where there is only just room for her +to pass. + +The rubbish soon becomes cumbersome. The insect collects it and then, +moving backwards, with its fore-legs closed over the load, it hoists +it up through the shaft and flings it outside, upon the mole-hill, +which rises by so much above the threshold of the burrow. Next come +the dainty finishing-touches: the milling of the wall, the +application of a glaze of better-quality clay, the assiduous +polishing with the long-suffering tongue, the waterproof coating and +the jarlike mouth, a masterpiece of pottery in which the stopping- +plug will be fixed when the time comes for locking the door of the +room. And all this has to be done with mathematical precision. + +No, because of this perfection, the grubs' chambers could never be +work done casually from day to day, as the ripe eggs descend from the +ovaries. They are prepared long beforehand, during the bad weather, +at the end of March and in April, when flowers are scarce and the +temperature subject to sudden changes. This thankless period, often +cold, liable to hail-storms, is spent in making ready the home. Alone +at the bottom of her shaft, which she rarely leaves, the mother works +at her children's apartments, lavishing upon them those finishing- +touches which leisure allows. They are completed, or very nearly, +when May comes with the radiant sunshine and wealth of flowers. + +We see the evidence of these long preparations in the burrows +themselves, if we inspect them before the provisions are brought. All +of them show us cells, about a dozen in number, quite finished, but +still empty. To begin by getting all the huts built is a sensible +precaution: the mother will not have to turn aside from the delicate +task of harvesting and egg-laying in order to perform rough navvy's +work. + +Everything is ready by May. The air is balmy; the smiling lawns are +gay with a thousand little flowers, dandelions, rock-roses, tansies +and daisies, among which the harvesting Bee rolls gleefully, covering +herself with pollen. With her crop full of honey and the brushes of +her legs befloured, the Halictus returns to her village. Flying very +low, almost level with the ground, she hesitates, with sudden turns +and bewildered movements. It seems that the weak-sighted insect finds +its way with difficulty among the cottages of its little township. + +Which is its mole-hill among the many others near, all similar in +appearance? It cannot tell exactly save by the sign-board of certain +details known to itself alone. Therefore, still on the wing, tacking +from side to side, it examines the locality. The home is found at +last: the Halictus alights on the threshold of her abode and dives +into it quickly. + +What happens at the bottom of the pit must be the same thing that +happens in the case of the other Wild Bees. The harvester enters a +cell backwards; she first brushes herself and drops her load of +pollen; then, turning round, she disgorges the honey in her crop upon +the floury mass. This done, the unwearied one leaves the burrow and +flies away, back to the flowers. After many journeys, the stack of +provisions in the cell is sufficient. This is the moment to bake the +cake. + +The mother kneads her flour, mingles it sparingly with honey. The +mixture is made into a round loaf, the size of a pea. Unlike our own +loaves, this one has the crust inside and the crumb outside. The +middle part of the roll, the ration which will be consumed last, when +the grub has acquired some strength, consists of almost nothing but +dry pollen. The Bee keeps the dainties in her crop for the outside of +the loaf, whence the feeble grub-worm is to take its first mouthfuls. +Here it is all soft crumb, a delicious sandwich with plenty of honey. +The little breakfast-roll is arranged in rings regulated according to +the age of the nurseling: first the syrupy outside and at the very +end the dry inside. Thus it is ordained by the economics of the +Halictus. + +An egg bent like a bow is laid upon the sphere. According to the +generally-accepted rule, it now only remains to close the cabin. +Honey-gatherers--Anthophorae, Osmiae, Mason-bees and many others-- +usually first collect a sufficient stock of food and then, having +laid the egg, shut up the cell, to which they need pay no more +attention. The Halicti employ a different method. The compartments, +each with its round loaf and its egg--the tenant and his provisions-- +are not closed up. As they all open into the common passage of the +burrow, the mother is able, without leaving her other occupations, to +inspect them daily and enquire tenderly into the progress of her +family. I imagine, without possessing any certain proof, that from +time to time she distributes additional provisions to the grubs, for +the original loaf appears to me a very frugal ration compared with +that served by the other Bees. + +Certain hunting Hymenoptera, the Bembex-wasps, for instance, are +accustomed to furnish the provisions in instalments: so that the grub +may have fresh though dead game, they fill the platter each day. The +Halictus mother has not these domestic necessities, as her provisions +keep more easily; but still she might well distribute a second +portion of flour to the larvae, when their appetite attains its +height. I can see nothing else to explain the open doors of the cells +during the feeding-period. + +At last the grubs, close-watched and fed to repletion, have achieved +the requisite degree of fatness; they are on the eve of being +transformed into pupae. Then and not till then the cells are closed: +a big clay stopper is built by the mother into the spreading mouth of +the jug. Henceforth the maternal cares are over. The rest will come +of itself. + +Hitherto we have witnessed only the peaceful details of the +housekeeping. Let us go back a little and we shall be witnesses of +rampant brigandage. In May, I visit my most populous village daily, +at about ten o'clock in the morning, when the victualling-operations +are in full swing. Seated on a low chair in the sun, with my back +bent and my arms upon my knees, I watch, without moving, until +dinner-time. What attracts me is a parasite, a trumpery Gnat, the +bold despoiler of the Halictus. + +Has the jade a name? I trust so, without, however, caring to waste my +time in enquiries that can have no interest for the reader. Facts +clearly stated are preferable to the dry minutiae of nomenclature. +Let me content myself with giving a brief description of the culprit. +She is a Dipteron, or Fly, five millimetres long. (.195 inch.-- +Translator's Note.) Eyes, dark-red; face, white. Corselet, pearl- +grey, with five rows of fine black dots, which are the roots of stiff +bristles pointing backwards. Greyish belly, pale below. Black legs. + +She abounds in the colony under observation. Crouching in the sun, +near a burrow, she waits. As soon as the Halictus arrives from her +harvesting, her legs yellow with pollen, the Gnat darts forth and +pursues her, keeping behind her in all the turns of her oscillating +flight. At last, the Bee suddenly dives indoors. No less suddenly the +other settles on the mole-hill, quite close to the entrance. +Motionless, with her head turned towards the door of the house, she +waits for the Bee to finish her business. The latter reappears at +last and, for a few seconds, stands on the threshold, with her head +and thorax outside the hole. The Gnat, on her side, does not stir. + +Often, they are face to face, separated by a space no wider than a +finger's breadth. Neither of them shows the least excitement. The +Halictus--judging, at least, by her tranquillity--takes no notice of +the parasite lying in wait for her; the parasite, on the other hand, +displays no fear of being punished for her audacity. She remains +imperturbable, she, the dwarf, in the presence of the colossus who +could crush her with one blow. + +In vain I watch anxiously for some sign of apprehension on either +side: nothing in the Halictus points to a knowledge of the danger run +by her family; nor does the Gnat betray any dread of swift +retribution. Plunderer and plundered stare at each other for a +moment; and that is all. + +If she liked, the amiable giantess could rip up with her claw the +tiny bandit who ruins her home; she could crunch her with her +mandibles, run her through with her stiletto. She does nothing of the +sort, but leaves the robber in peace, to sit quite close, motionless, +with her red eyes fixed on the threshold of the house. Why this +fatuous clemency? + +The Bee flies off. Forthwith, the Gnat walks in, with no more +ceremony than if she were entering her own place. She now chooses +among the victualled cells at her ease, for they are all open, as I +have said; she leisurely deposits her eggs. No one will disturb her +until the Bee's return. To flour one's legs with pollen, to distend +one's crop with syrup is a task that takes long a-doing; and the +intruder, therefore, has time and to spare wherein to commit her +felony. Moreover, her chronometer is well-regulated and gives the +exact measure of the Bee's length of absence. When the Halictus comes +back from the fields, the Gnat has decamped. In some favourable spot, +not far from the burrow, she awaits the opportunity for a fresh +misdeed. + +What would happen if a parasite were surprised at her work by the +Bee? Nothing serious. I see them, greatly daring, follow the Halictus +right into the cave and remain there for some time while the mixture +of pollen and honey is being prepared. Unable to make use of the +paste so long as the harvester is kneading it, they go back to the +open air and wait on the threshold for the Bee to come out. They +return to the sunlight, calmly, with unhurried steps: a clear proof +that nothing untoward has occurred in the depths where the Halictus +works. + +A tap on the Gnat's neck, if she become too enterprising in the +neighbourhood of the cake: that is all that the lady of the house +seems to allow herself, to drive away the intruder. There is no +serious affray between the robber and the robbed. This is apparent +from the self-possessed manner and undamaged condition of the dwarf +who returns from visiting the giantess engaged down in the burrow. + +The Bee, when she comes home, whether laden with provisions or not, +hesitates, as I have said, for a while; in a series of rapid zigzags, +she moves backwards, forwards and from side to side, at a short +distance from the ground. This intricate flight at first suggests the +idea that she is trying to lead her persecutress astray by means of +an inextricable tangle of marches and countermarches. That would +certainly be a prudent move on the Bee's part; but so much wisdom +appears to be denied her. + +It is not the enemy that is disturbing her, but rather the difficulty +of finding her own house amid the confusion of the mole-hills, +encroaching one upon the other, and all the alleys of the little +township, which, owing to landslips of fresh rubbish, alter in +appearance from one day to the next. Her hesitation is manifest, for +she often blunders and alights at the entrance to a burrow that is +not hers. The mistake is at once perceived from the slight +indications of the doorway. + +The search is resumed with the same see-sawing flights, mingled with +sudden excursions to a distance. At last, the burrow is recognized. +The Halictus dives into it with a rush; but, however prompt her +disappearance underground, the Gnat is there, perched on the +threshold with her eyes turned to the entrance, waiting for the Bee +to come out, so that she may visit the honey-jars in her turn. + +When the owner of the house ascends, the other draws back a little, +just enough to leave a free passage and no more. Why should she put +herself out? the meeting is so peaceful that, short of further +information, one would not suspect that a destroyer and destroyed +were face to face. Far from being intimidated by the sudden arrival +of the Halictus, the Gnat pays hardly any attention; and, in the same +way, the Halictus takes no notice of her persecutress, unless the +bandit pursue her and worry her on the wing. Then, with a sudden +bend, the Bee makes off. + +Even so do Philanthus apivorus (The Bee-hunting Wasp. Cf. "Social +Life in the Insect World": chapter 13.--Translator's Note.) and the +other game-hunters behave when the Tachina is at their heels seeking +the chance to lay her egg on the morsel about to be stored away. +Without jostling the parasite which they find hanging around the +burrow, they go indoors quite peaceably; but, on the wing, perceiving +her after them, they dart off wildly. The Tachina, however, dares not +go down to the cells where the huntress stacks her provisions; she +prudently waits at the door for the Philanthus to arrive. The crime, +the laying of the egg, is committed at the very moment when the +victim is about to vanish underground. + +The troubles of the parasite of the Halictus are of quite another +kind. The homing Bee has her honey in her crop and her pollen on her +leg-brushes: the first is inaccessible to the thief; the second is +powdery and would give no resting-place to the egg. Besides, there is +not enough of it yet: to collect the wherewithal for that round loaf +of hers, the Bee will have to make repeated journeys. When the +necessary amount is obtained, she will knead it with the tip of her +mandibles and shape it with her feet into a little ball. The Gnat's +egg, were it present among the materials, would certainly be in +danger during this manipulation. + +The alien egg, therefore, must be laid on the finished bread; and, as +the preparation takes place underground, the parasite is needs +obliged to go down to the Halictus. With inconceivable daring, she +does go down, even when the Bee is there. Whether through cowardice +or silly indulgence, the dispossessed insect lets the other have its +way. + +The object of the Gnat, with her tenacious lying-in-wait and her +reckless burglaries, is not to feed herself at the harvester's +expense: she could get her living out of the flowers with much less +trouble than her thieving trade involves. The most, I think, that she +can allow herself to do in the Halictus' cellars is to take one +morsel just to ascertain the quality of the victuals. Her great, her +sole business is to settle her family. The stolen goods are not for +herself, but for her offspring. + +Let us dig up the pollen-loaves. We shall find them most often +crumbled with no regard to economy, simply frittered away. We shall +see two or three maggots, with pointed mouths, moving in the yellow +flour scattered over the floor of the cell. These are the Gnat's +progeny. With them we sometimes find the lawful owner, the grub-worm +of the Halictus, but stunted and emaciated with fasting. His +gluttonous companions, without otherwise molesting him, deprive him +of the best of everything. The wretched starveling dwindles, shrivels +up and soon disappears from view. His corpse, a mere atom, blended +with the remaining provisions, supplies the maggots with one mouthful +the more. + +And what does the Halictus mother do in this disaster? She is free to +visit her grubs at any moment; she has but to put her head into the +passage of the house: she cannot fail to be apprised of their +distress. The squandered loaf, the swarming mass of vermin tell their +own tale. Why does she not take the intruders by the skin of the +abdomen? To grind them to powder with her mandibles, to fling them +out of doors were the business of a second. And the foolish creature +never thinks of it, leaves the ravagers in peace! + +She does worse. When the time of the nymphosis comes, the Halictus +mother goes to the cells rifled by the parasite and closes them with +an earthen plug as carefully as she does the rest. This final +barricade, an excellent precaution when the cot is occupied by an +Halictus in course of metamorphosis, becomes the height of absurdity +when the Gnat has passed that way. Instinct does not hesitate in the +face of this ineptitude: it seals up emptiness. I say, emptiness, +because the crafty maggot hastens to decamp the instant that the +victuals are consumed, as though it foresaw an insuperable obstacle +for the coming Fly: it quits the cell before the Bee closes it. + +To rascally guile the parasite adds prudence. All, until there is +none of them left, abandon the clay homes which would be their +undoing once the entrance was plugged up. The earthen niche, so +grateful to the tender skin, thanks to its polished coating, so free +from humidity, thanks to its waterproof glaze, ought, one would +think, to make an excellent waiting-place. The maggots will have none +of it. Lest they should find themselves walled in when they become +frail Gnats, they go away and disperse in the neighbourhood of the +ascending shaft. + +My digging operations, in fact, always reveal the pupae outside the +cells, never inside. I find them enshrined, one by one, in the body +of the clayey earth, in a narrow recess which the emigrant worm has +contrived to make for itself. Next spring, when the hour comes for +leaving, the adult insect has but to creep through the rubbish, which +is easy work. + +Another and no less imperative reason compels this change of abode on +the parasite's part. In July, a second generation of the Halictus is +procreated. The Gnat, reduced on her side to a single brood, remains +in the pupa state and awaits the spring of the following year before +effecting her transformation. The honey-gather resumes her work in +her native village; she avails herself of the pits and cells +constructed in the spring, saving no little time thereby. The whole +elaborate structure has remained in good condition. It needs but a +few repairs to make the old house habitable. + +Now what would happen if the Bee, so scrupulous in matters of +cleanliness, were to find a pupa in the cell which she is sweeping? +She would treat the cumbersome object as she would a piece of old +plaster. It would be no more to her than any other refuse, a bit of +gravel, which, seized with the mandibles, crushed perhaps, would be +sent to join the rubbish-heap outside. Once removed from the soil and +exposed to the inclemencies of the weather, the pupa would inevitably +perish. + +I admire this intelligent foresight of the maggot, which forgoes the +comfort of the moment for the security of the future. Two dangers +threaten it: to be immured in a casket whence the Fly can never +issue; or else to die out of doors, in the unkindly air, when the Bee +sweeps out the restored cells. To avoid this twofold peril, it +decamps before the door is closed, before the July Halictus sets her +house in order. + +Let us now see what comes of the parasite's intrusion. In the course +of June, when peace is established in the Halictus' home, I dig up my +largest village, comprising some fifty burrows in all. None of the +sorrows of this underworld shall escape me. There are four of us +engaged in sifting the excavated earth through our fingers. What one +has examined another takes up and examines; and then another and +another yet. The returns are heartrending. We do not succeed in +finding one single nymph of the Halictus. The whole of the populous +city has perished; and its place has been taken by the Gnat. There is +a glut of that individual's pupae. I collect them in order to trace +their evolution. + +The year runs its course; and the little russet kegs, into which the +original maggots have hardened and contracted, remain stationary. +They are seeds endowed with latent life. The heats of July do not +rouse them from their torpor. In that month, the period of the second +generation of the Halictus, there is a sort of truce of God: the +parasite rests and the Bee works in peace. If hostilities were to be +resumed straight away, as murderous in summer as they were in spring, +the progeny of the Halictus, too cruelly smitten, might possibly +disappear altogether. This lull readjusts the balance. + +In April, when the Zebra Halictus, in search of a good place for her +burrows, roams up and down the garden paths with her oscillating +flight, the parasite, on its side, hastens to hatch. Oh, the precise +and terrible agreement between those two calendars, the calendar of +the persecutor and the persecuted! At the very moment when the Bee +comes out, here is the Gnat: she is ready to begin her deadly +starving-process all over again. + +Were this an isolated case, one's mind would not dwell upon it: an +Halictus more or less in the world makes little difference in the +general balance. But, alas, brigandage in all its forms is the rule +in the eternal conflict of living things! From the lowest to the +highest, every producer is exploited by the unproductive. Man +himself, whose exceptional rank ought to raise him above such +baseness, excels in this ravening lust. He says to himself that +business means getting hold of other people's cash, even as the Gnat +says to herself that business means getting hold of the Halictus' +honey. And, to play the brigand to better purpose, he invents war, +the art of killing wholesale and of doing with glory that which, when +done on a smaller scale, leads to the gallows. + +Shall we never behold the realization of that sublime vision which is +sung on Sundays in the smallest village-church: Gloria in excelsis +Deo, et in terra pax hominibus bonae voluntatis! If war affected +humanity alone, perhaps the future would have peace in store for us, +seeing that generous minds are working for it with might and main; +but the scourge also rages among the lower animals, which in their +obstinate way, will never listen to reason. Once the evil is laid +down as a general condition, it perhaps becomes incurable. Life in +the future, it is to be feared, will be what it is to-day, a +perpetual massacre. + +Whereupon, by a desperate effort of the imagination, one pictures to +oneself a giant capable of juggling with the planets. He is +irresistible strength; he is also law and justice. He knows of our +battles, our butcheries, our farm-burnings, our town-burnings, our +brutal triumphs; he knows our explosives, our shells, our torpedo- +boats, our ironclads and all our cunning engines of destruction; he +knows as well the appalling extent of the appetites among all +creatures, down to the very lowest. Well, if that just and mighty one +held the earth under his thumb, would he hesitate whether he ought to +crush it? + +He would not hesitate...He would let things take their course. He +would say to himself: + +'The old belief is right; the earth is a rotten apple, gnawed by the +vermin of evil. It is a first crude attempt, a step towards a +kindlier destiny. Let it be: order and justice are waiting at the +end.' + + +CHAPTER 13. THE HALICTI: THE PORTRESS. + +Leaving our village is no very serious matter when we are children. +We even look on it as a sort of holiday. We are going to see +something new, those magic pictures of our dreams. With age come +regrets; and the close of life is spent in stirring up old memories. +Then the beloved village reappears, in the biograph of the mind, +embellished, transfigured by the glow of those first impressions; and +the mental image, superior to the reality, stands out in amazingly +clear relief. The past, the far-off past, was only yesterday; we see +it, we touch it. + +For my part, after three-quarters of a century, I could walk with my +eyes closed straight to the flat stone where I first heard the soft +chiming note of the Midwife Toad; yes, I should find it to a +certainty, if time, which devastates all things, even the homes of +Toads, has not moved it or perhaps left it in ruins. + +I see, on the margin of the brook, the exact position of the alder- +trees whose tangled roots, deep under the water, were a refuge for +the Crayfish. I should say: + +'It is just at the foot of that tree that I had the unutterable bliss +of catching a beauty. She had horns so long...and enormous claws, +full of meat, for I got her just at the right time.' + +I should go without faltering to the ash under whose shade my heart +beat so loudly one sunny spring morning. I had caught sight of a sort +of white, cottony ball among the branches. Peeping from the depths of +the wadding was an anxious little head with a red hood to it. O what +unparalleled luck! It was a Goldfinch, sitting on her eggs. + +Compared with a find like this, lesser events do not count. Let us +leave them. In any case, they pale before the memory of the paternal +garden, a tiny hanging garden of some thirty paces by ten, situated +right at the top of the village. The only spot that overlooks it is a +little esplanade on which stands the old castle (The Chateau de +Saint-Leons standing just outside and above the village of Saint- +Leons, where the author was born in 1823. Cf. "The Life of the Fly": +chapters 6 and 7.--Translator's Note.) with the four turrets that +have now become dovecotes. A steep path takes you up to this open +space. From my house on, it is more like a precipice than a slope. +Gardens buttressed by walls are staged in terraces on the sides of +the funnel-shaped valley. Ours is the highest; it is also the +smallest. + +There are no trees. Even a solitary apple-tree would crowd it. There +is a patch of cabbages, with a border of sorrel, a patch of turnips +and another of lettuces. That is all we have in the way of garden- +stuff; there is no room for more. Against the upper supporting-wall, +facing due south, is a vine-arbour which, at intervals, when the sun +is generous, provides half a basketful of white muscatel grapes. +These are a luxury of our own, greatly envied by the neighbours, for +the vine is unknown outside this corner, the warmest in the village. + +A hedge of currant-bushes, the only safeguard against a terrible +fall, forms a parapet above the next terrace. When our parents' +watchful eyes are off us, we lie flat on our stomachs, my brother and +I, and look into the abyss at the foot of the wall bulging under the +thrust of the land. It is the garden of monsieur le notaire. + +There are beds with box-borders in that garden; there are pear-trees +reputed to give pears, real pears, more or less good to eat when they +have ripened on the straw all through the late autumn. In our +imagination, it is a spot of perpetual delight, a paradise, but a +paradise seen the wrong way up: instead of contemplating it from +below, we gaze at it from above. How happy they must be with so much +space and all those pears! + +We look at the hives, around which the hovering Bees make a sort of +russet smoke. They stand under the shelter of a great hazel. The tree +has sprung up all of itself in a fissure of the wall, almost on the +level of our currant-bushes. While it spreads its mighty branches +over the notary's hives, its roots, at least, are on our land. It +belongs to us. The trouble is to gather the nuts. + +I creep along astride the strong branches projecting horizontally +into space. If I slip or if the support breaks, I shall come to grief +in the midst of the angry Bees. I do not slip and the support does +not break. With the bent switch which my brother hands me, I bring +the finest clusters within my reach. I soon fill my pockets. Moving +backwards, still straddling my branch, I recover terra firma. O +wondrous days of litheness and assurance, when, for a few filberts, +on a perilous perch we braved the abyss! + +Enough. These reminiscences, so dear to my dreams, do not interest +the reader. Why stir up more of them? I am content to have brought +this fact into prominence: the first glimmers of light penetrating +into the dark chambers of the mind leave an indelible impression, +which the years make fresher instead of dimmer. + +Obscured by everyday worries, the present is much less familiar to +us, in its petty details, than the past, with childhood's glow upon +it. I see plainly in my memory what my prentice eyes saw; and I +should never succeed in reproducing with the same accuracy what I saw +last week. I know my village thoroughly, though I quitted it so long +ago; and I know hardly anything of the towns to which the +vicissitudes of life have brought me. An exquisitely sweet link binds +us to our native soil; we are like the plant that has to be torn away +from the spot where it put out its first roots. Poor though it be, I +should love to see my own village again; I should like to leave my +bones there. + +Does the insect in its turn receive a lasting impression of its +earliest visions? Has it pleasant memories of its first surroundings? +We will not speak of the majority, a world of wandering gipsies who +establish themselves anywhere provided that certain conditions be +fulfilled; but the others, the settlers, living in groups: do they +recall their native village? Have they, like ourselves, a special +affection for the place which saw their birth? + +Yes, indeed they have: they remember, they recognize the maternal +abode, they come back to it, they restore it, they colonize it anew. +Among many other instances, let us quote that of the Zebra Halictus. +She will show us a splendid example of love for one's birthplace +translating itself into deeds. + +The Halictus' spring family acquire the adult form in a couple of +months or so; they leave the cells about the end of June. What goes +on inside these neophytes as they cross the threshold of the burrow +for the first time? Something, apparently, that may be compared with +our own impressions of childhood. An exact and indelible image is +stamped on their virgin memories. Despite the years, I still see the +stone whence came the resonant notes of the little Toads, the parapet +of currant-bushes, the notary's garden of Eden. These trifles make +the best part of my life. The Halictus sees in the same way the blade +of grass whereon she rested in her first flight, the bit of gravel +which her claw touched in her first climb to the top of the shaft. +She knows her native abode by heart just as I know my village. The +locality has become familiar to her in one glad, sunny morning. + +She flies off, seeks refreshment on the flowers near at hand and +visits the fields where the coming harvests will be gathered. The +distance does not lead her astray, so faithful are her impressions of +her first trip; she finds the encampment of her tribe; among the +burrows of the village, so numerous and so closely resembling one +another, she knows her own. It is the house where she was born, the +beloved house with its unforgettable memories. + +But, on returning home, the Halictus is not the only mistress of the +house. The dwelling dug by the solitary Bee in early spring remains, +when summer comes, the joint inheritance of the members of the +family. There are ten cells, or thereabouts, underground. Now from +these cells there have issued none but females. This is the rule +among the three species of Halicti that concern us now and probably +also among many others, if not all. They have two generations in each +year. The spring one consists of females only; the summer one +comprises both males and females, in almost equal numbers. We shall +return to this curious subject in our next chapter. + +The household, therefore, if not reduced by accidents, above all if +not starved by the usurping Gnat, would consist of half-a-score of +sisters, none but sisters, all equally industrious and all capable of +procreating without a nuptial partner. On the other hand, the +maternal dwelling is no hovel; far from it: the entrance-gallery, the +principal room of the house, will serve quite well, after a few odds +and ends of refuse have been swept away. This will be so much gained +in time, ever precious to the Bee. The cells at the bottom, the clay +cabins, are also nearly intact. To make use of them, it will be +enough for the Halictus to polish up the stucco with her tongue. + +Well, which of the survivors, all equally entitled to the succession, +will inherit the house? There are six of them, seven, or more, +according to the chances of mortality. To whose share will the +maternal dwelling fall? + +There is no quarrel between the interested parties. The mansion is +recognized as common property without dispute. The sisters come and +go peacefully through the same door, attend to their business, pass +and let the others pass. Down at the bottom of the pit, each has her +little demesne, her group of cells dug at the cost of fresh toil, +when the old ones, now insufficient in number, are occupied. In these +recesses, which are private estates, each mother works by herself, +jealous of her property and of her privacy. Every elsewhere, traffic +is free to all. + +The exits and entrances in the working fortress provide a spectacle +of the highest interest. A harvester arrives from the fields, the +feather-brushes of her legs powdered with pollen. If the door be +open, the Bee at once dives underground. To tarry on the threshold +would mean waste of time; and the business is urgent. Sometimes, +several appear upon the scene at almost the same moment. The passage +is too narrow for two, especially when they have to avoid any +untimely contact that would make the floury burden fall to the floor. +The nearest to the opening enters quickly. The others, drawn up on +the threshold in order of their arrival, respectful of one another's +rights, await their turn. As soon as the first disappears, the second +follows after her and is herself swiftly followed by the third and +then the others, one by one. + +Sometimes, again, there is a meeting between a Bee about to come out +and a Bee about to go in. Then the latter draws back a little and +makes way for the former. The politeness is reciprocal. I see some +who, when on the point of emerging from the pit, go down again and +leave the passage free for the one who has just arrived. Thanks to +this mutual spirit of accommodation, the business of the house +proceeds without impediment. + +Let us keep our eyes open. There is something better than the well- +preserved order of the entrances. When an Halictus appears, returning +from her round of the flowers, we see a sort of trap-door, which +closed the house, suddenly fall and give a free passage. As soon as +the new arrival has entered, the trap rises back into its place, +almost level with the ground, and closes the entrance anew. The same +thing happens when the insects go out. At a request from within, the +trap descends, the door opens and the Bee flies away. The outlet is +closed forthwith. + +What can this valve be which, descending or ascending in the cylinder +of the pit, after the fashion of a piston, opens and closes the house +at each departure and at each arrival? It is an Halictus, who has +become the portress of the establishment. With her large head, she +makes an impassable barrier at the top of the entrance-hall. If any +one belonging to the house wants to go in or out, she 'pulls the +cord,' that is to say, she withdraws to a spot where the gallery +becomes wider and leaves room for two. The other passes. She then at +once returns to the orifice and blocks it with the top of her head. +Motionless, ever on the look-out, she does not leave her post save to +drive away importunate visitors. + +Let us profit by her brief appearances outside to take a look at her. +We recognize in her an Halictus similar to the others, which are now +busy harvesting; but the top of her head is bald and her dress is +dingy and thread-bare. All the nap is gone; and one can hardly make +out the handsome stripes of red and brown which she used to have. +These tattered, work-worn garments make things clear to us. + +This Bee who mounts guard and performs the office of a portress at +the entrance to the burrow is older than the others. She is the +foundress of the establishment, the mother of the actual workers, the +grandmother of the present grubs. In the springtime of her life, +three months ago, she wore herself out in solitary labours. Now that +her ovaries are dried up, she takes a well-earned rest. No, rest is +hardly the word. She still works, she assists the household to the +best of her power. Incapable of being a mother for a second time, she +becomes a portress, opens the door to the members of her family and +makes strangers keep their distance. + +The suspicious Kid (In La Fontaine's fable, "Le Loup, la Chevre et le +Chevreau."--Translator's Note.), looking through the chink, said to +the Wolf: + +'Show me a white foot, or I shan't open the door.' + +No less suspicious, the grandmother says to each comer: + +'Show me the yellow foot of an Halictus, or you won't be let in.' + +None is admitted to the dwelling unless she be recognized as a member +of the family. + +See for yourselves. Near the burrow passes an Ant, an unscrupulous +adventuress, who would not be sorry to know the meaning of the +honeyed fragrance that rises from the bottom of the cellar. + +"Be off, or you'll catch it!'says the portress, wagging her neck. + +As a rule the threat suffices. The Ant decamps. Should she insist, +the watcher leaves her sentry-box, flings herself upon the saucy +jade, buffets her and drives her away. The moment the punishment has +been administered, she returns to her post. + +Next comes the turn of a Leaf-cutter (Megachile albocincta, PEREZ), +which, unskilled in the art of burrowing, utilizes, after the manner +of her kin, the old galleries dug by others. Those of the Zebra +Halictus suit her very well, when the terrible Gnat has left them +vacant for lack of heirs. Seeking for a home wherein to stack her +robinia-leaf honey-pots, she often makes a flying inspection of my +colonies of Halicti. A burrow seems to take her fancy; but, before +she sets foot on earth, her buzzing is noticed by the sentry, who +suddenly darts out and makes a few gestures on the threshold of her +door. That is all. The Leaf-cutter has understood. She moves on. + +Sometimes, the Megachile has time to alight and insert her head into +the mouth of the pit. In a moment, the portress is there, comes a +little higher and bars the way. Follows a not very serious contest. +The stranger quickly recognizes the rights of the first occupant and, +without insisting, goes to seek an abode elsewhere. + +An accomplished marauder (Caelioxys caudata, SPIN.), a parasite of +the Megachile, receives a sound drubbing under my eyes. She thought, +the feather-brain, that she was entering the Leaf-Cutter's +establishment! She soon finds out her mistake; she meets the door- +keeping Halictus, who administers a sharp correction. She makes off +at full speed. And so with the others which, through inadvertence or +ambition, seek to enter the burrow. + +The same intolerance exists among the different grandmothers. About +the middle of July, when the animation of the colony is at its +height, two sets of Halicti are easily distinguishable: the young +mothers and the old. The former, much more numerous, brisk of +movement and smartly arrayed, come and go unceasingly from the +burrows to the fields and from the fields to the burrows. The latter, +faded and dispirited, wander idly from hole to hole. They look as +though they had lost their way and were incapable of finding their +homes. Who are these vagabonds? I see in them afflicted ones bereft +of a family through the act of the odious Gnat. Many burrows have +been altogether exterminated. At the awakening of summer, the mother +found herself alone. She left her empty house and went off in search +of a dwelling where there were cradles to defend, a guard to mount. +But those fortunate nests already have their overseer, the foundress, +who, jealous of her rights, gives her unemployed neighbour a cold +reception. One sentry is enough; two would merely block the narrow +guard-room. + +I am privileged at times to witness a fight between two grandmothers. +When the tramp in quest of employment appears outside the door, the +lawful occupant does not move from her post, does not withdraw into +the passage, as she would before an Halictus returning from the +fields. Far from making way, she threatens the intruder with her feet +and mandibles. The other retaliates and tries to force her way in +notwithstanding. Blows are exchanged. The fray ends by the defeat of +the stranger, who goes off to pick a quarrel elsewhere. + +These little scenes afford us a glimpse of certain details of the +highest interest in the habits of the Zebra Halictus. The mother who +builds her nest in the spring no longer leaves her home, once her +works are finished. Shut up at the bottom of the burrow, busied with +the thousand cares of housekeeping, or else drowsing, she waits for +her daughters to come out. When, in the summer heats, the life of the +village recommences, having nought to do outside as a harvester, she +stands sentry at the entrance to the hall, so as to let none in save +the workers of the home, her own daughters. She wards off evilly- +disposed visitors. None can enter without the door-keeper's consent. + +There is nothing to tell us that the watcher ever deserts her post. +Not once do I see her leave her house to go and seek some refreshment +from the flowers. Her age and her sedentary occupation, which +involves no great fatigue, perhaps relieve her of the need of +nourishment. Perhaps, also, the young ones returning from their +plundering may from time to time disgorge a drop of the contents of +their crops for her benefit. Fed or unfed, the old one no longer goes +out. + +But what she does need is the joys of an active family. Many are +deprived of these. The Gnat's burglary has destroyed the busy +household. The sorely-tried Bees abandon the deserted burrow. It is +they who, ragged and careworn, wander through the village. When they +move, their flight is only a short one; more often they remain +motionless. It is they who, soured in their tempers, attack their +fellows and seek to dislodge them. They grow rarer and more languid +from day to day; then they disappear for good. What has become of +them? The little Grey Lizard had his eye on them: they are easily +snapped up. + +Those settled in their own demesne, those who guard the honey-factory +wherein their daughters, the heiresses of the maternal establishment, +are at work, display wonderful vigilance. The more I see of them, the +more I admire them. In the cool hours of the early morning, when the +pollen-flour is not sufficiently ripened by the sun and while the +harvesters are still indoors, I see them at their posts, at the top +of the gallery. Here, motionless, their heads flush with the earth, +they bar the door to all invaders. If I look at them closely, they +retreat a little and, in the shadow, await the indiscreet observer's +departure. + +I return when the harvesting is in full swing, between eight o'clock +and twelve. There is now, as the Halicti go in or out, a succession +of prompt withdrawals to open the door and of ascents to close it. +The portress is in the full exercise of her functions. + +In the afternoon, the heat is too great and the workers do not go to +the fields. Retiring to the bottom of the house, they varnish the +new cells, they make the round loaf that is to receive the egg. The +grandmother is still upstairs, stopping the door with her bald head. +For her, there is no siesta during the stifling hours: the safety of +the household requires her to forgo it. + +I come back again at nightfall, or even later. By the light of a +lantern, I again behold the overseer, as zealous and assiduous as in +the day-time. The others are resting, but not she, for fear, +apparently, of nocturnal dangers known to herself alone. Does she +nevertheless end by descending to the quiet of the floor below? It +seems probable, so essential must rest be, after the fatigue of such +a vigil! + +It is evident that, guarded in this manner, the burrow is exempt from +calamities similar to those which, too often, depopulate it in May. +Let the Gnat come now, if she dare, to steal the Halictus' loaves! +Let her lie in wait as long as she will! Neither her audacity nor her +slyness will make her escape the lynx eyes of the sentinel, who will +put her to flight with a threatening gesture or, if she persist, +crush her with her nippers. She will not come; and we know the +reason: until spring returns, she is underground in the pupa state. + +But, in her absence, there is no lack, among the Fly rabble, of other +batteners on the toil of their fellow insects. Whatever the job, +whatever the plunder, you will find parasites there. And yet, for all +my daily visits, I never catch one of these in the neighbourhood of +the summer burrows. How cleverly the rascals ply their trade! How +well aware are they of the guard who keeps watch at the Halictus' +door! There is no foul deed possible nowadays; and the result is that +no Fly puts in an appearance and the tribulations of last spring are +not repeated. + +The grandmother who, dispensed by age from maternal bothers, mounts +guard at the entrance of the home and watches over the safety of the +family, tells us that in the genesis of the instincts sudden births +occur; she shows us the existence of a spontaneous aptitude which +nothing, either in her own past conduct or in the actions of her +daughters, could have led us to suspect. Timorous in her prime, in +the month of May, when she lived alone in the burrow of her making, +she has become gifted, in her decline, with a superb contempt of +danger and dares in her impotence what she never dared do in her +strength. + +Formerly, when her tyrant, the Gnat, entered the house in her +presence, or, more often, stood face to face with her at the +entrance, the silly Bee did not stir, did not even threaten the red- +eyed bandit, the dwarf whose doom she could so easily have sealed. +Was it terror on her part? No, for she attended to her duties with +her usual punctiliousness; no, for the strong do not allow themselves +to be thus paralysed by the weak. It was ignorance of the danger, it +was sheer fecklessness. + +And behold, to-day, the ignoramus of three months ago knows the +peril, knows it well, without serving any apprenticeship. Every +stranger who appears is kept at a distance, without distinction of +size or race. If the threatening gesture be not enough, the keeper +sallies forth and flings herself upon the persistent one. Cowardice +has developed into courage. + +How has this change been brought about? I should like to picture the +Halictus gaining wisdom from the misfortunes of the spring and +capable thenceforth of looking out for danger; I would gladly credit +her with having learnt in the stern school of experience the +advantages of a patrol. I must give up the idea. If, by dint of +gradual little acts of progress, the Bee has achieved the glorious +invention of a janitress, how comes it that the fear of thieves is +intermittent? It is true that, being by herself in May, she cannot +stand permanently at her door: the business of the house takes +precedence of everything else. But she ought, at any rate as soon as +her offspring are victimized, to know the parasite and give chase +when, at every moment, she finds her almost under her feet and even +in her house. Yet she pays no attention to her. + +The bitter experience of her ancestors, therefore, has bequeathed +nothing to her of a nature to alter her placid character; nor have +her own tribulations aught to do with the sudden awakening of her +vigilance in July. Like ourselves, animals have their joys and their +sorrows. They eagerly make the most of the former; they fret but +little about the latter, which, when all is said, is the best way of +achieving a purely animal enjoyment of life. To mitigate these +troubles and protect the progeny there is the inspiration of +instinct, which is able without the counsels of experience to give +the Halicti a portress. + +When the victualling is finished, when the Halicti no longer sally +forth on harvesting intent nor return all befloured with their +spoils, the old Bee is still at her post, vigilant as ever. The final +preparations for the brood are made below; the cells are closed. The +door will be kept until everything is finished. Then grandmother and +mothers leave the house. Exhausted by the performance of their duty, +they go, somewhere or other, to die. + +In September appears the second generation, comprising both males and +females. I find both sexes wassailing on the flowers, especially the +Compositae, the centauries and thistles. They are not harvesting now: +they are refreshing themselves, holding high holiday, teasing one +another. It is the wedding-time. Yet another fortnight and the males +will disappear, henceforth useless. The part of the idlers is played. +Only the industrious ones remain, the impregnated females, who go +through the winter and set to work in April. + +I do not know their exact haunt during the inclement season. I +expected them to return to their native burrow, an excellent dwelling +for the winter, one would think. Excavations made in January showed +me my mistake. The old homes are empty, are falling to pieces owing +to the prolonged effect of the rains. The Zebra Halictus has +something better than these muddy hovels: she has snug corners in the +stone-heaps, hiding-places in the sunny walls and many other +convenient habitations. And so the natives of a village become +scattered far and wide. + +In April, the scattered ones reassemble from all directions. On the +well-flattened garden-paths a choice is made of the site for their +common labours. Operations soon begin. Close to the first who bores +her shaft there is soon a second one busy with hers; a third arrives, +followed by another and others yet, until the little mounds often +touch one another, while at times they number as many as fifty on a +surface of less than a square yard. + +One would be inclined, at first sight, to say that these groups are +accounted for by the insect's recollection of its birthplace, by the +fact that the villagers, after dispersing during the winter, return +to their hamlet. But it is not thus that things happen: the Halictus +scorns to-day the place that once suited her. I never see her occupy +the same patch of ground for two years in succession. Each spring she +needs new quarters. And there are plenty of them. + +Can this mustering of the Halicti be due to a wish to resume the old +intercourse with their friends and relations? Do the natives of the +same burrow, of the same hamlet, recognize one another? Are they +inclined to do their work among themselves rather than in the company +of strangers? There is nothing to prove it, nor is there anything to +disprove it. Either for this reason or for others, the Halictus likes +to keep with her neighbours. + +This propensity is pretty frequent among peace-lovers, who, needing +little nourishment, have no cause to fear competition. The others, +the big eaters, take possession of estates, of hunting-grounds from +which their fellows are excluded. Ask a Wolf his opinion of a brother +Wolf poaching on his preserves. Man himself, the chief of consumers, +makes for himself frontiers armed with artillery; he sets up posts at +the foot of which one says to the other: + +'Here's my side, there's yours. That's enough: now we'll pepper each +other.' + +And the rattle of the latest explosives ends the colloquy. + +Happy are the peace-lovers. What do they gain by their mustering? +With them it is not a defensive system, a concerted effort to ward +off the common foe. The Halictus does not care about her neighbour's +affairs. She does not visit another's burrow; she does not allow +others to visit hers. She has her tribulations, which she endures +alone; she is indifferent to the tribulations of her kind. She stands +aloof from the strife of her fellows. Let each mind her own business +and leave things at that. + +But company has its attractions. He lives twice who watches the life +of others. Individual activity gains by the sight of the general +activity; the animation of each one derives fresh warmth from the +fire of the universal animation. To see one's neighbours at work +stimulates one's rivalry. And work is the great delight, the real +satisfaction that gives some value to life. The Halictus knows this +well and assembles in her numbers that she may work all the better. + +Sometimes she assembles in such multitudes and over such extents of +ground as to suggest our own colossal swarms. Babylon and Memphis, +Rome and Carthage, London and Paris, those frantic hives, occur to +our mind if we can manage to forget comparative dimensions and see a +Cyclopean pile in a pinch of earth. + +It was in February. The almond-tree was in blossom. A sudden rush of +sap had given the tree new life; its boughs, all black and desolate, +seemingly dead, were becoming a glorious dome of snowy satin. I have +always loved this magic of the awakening spring, this smile of the +first flowers against the gloomy bareness of the bark. + +And so I was walking across the fields, gazing at the almond-trees' +carnival. Others were before me. An Osmia in a black velvet bodice +and a red woollen skirt, the Horned Osmia, was visiting the flowers, +dipping into each pink eye in search of a honeyed tear. A very small +and very modestly-dressed Halictus, much busier and in far greater +numbers, was flitting silently from blossom to blossom. Official +science calls her Halictus malachurus, K. The pretty little Bee's +godfather strikes me as ill-inspired. What has malachurus, calling +attention to the softness of the rump, to do in this connection? The +name of Early Halictus would better describe the almond-tree's little +visitor. + +None of the melliferous clan, in my neighbourhood at least, is +stirring as early as she is. She digs her burrows in February, an +inclement month, subject to sudden returns of frost. When none as +yet, even among her near kinswomen, dares to sally forth from winter- +quarters, she pluckily goes to work, shine the sun ever so little. +Like the Zebra Halictus, she has two generations a year, one in +spring and one in summer; like her, too, she settles by preference in +the hard ruts of the country roads. + +Her mole-hills, those humble mounds any two of which would go easily +into a Hen's egg, rise innumerous in my path, the path by the almond- +trees which is the happy hunting-ground of my curiosity to-day. This +path is a ribbon of road three paces wide, worn into ruts by the +Mule's hoofs and the wheels of the farm-carts. A coppice of holm-oaks +shelters it from the north wind. In this Eden with its well-caked +soil, its warmth and quiet, the little Halictus has multiplied her +mole-hills to such a degree that I cannot take a step without +crushing some of them. The accident is not serious: the miner, safe +underground, will be able to scramble up the crumbling sides of the +mine and repair the threshold of the trampled home. + +I make a point of measuring the density of the population. I count +from forty to sixty mole-hills on a surface of one square yard. The +encampment is three paces wide and stretches over nearly three- +quarters of a mile. How many Halicti are there in this Babylon? I do +not venture to make the calculation. + +Speaking of the Zebra Halictus, I used the words hamlet, village, +township; and the expressions were appropriate. Here the term city +hardly meets the case. And what reason can we allege for these +innumerable clusters? I can see but one: the charm of living +together, which is the origin of society. Like mingles with like, +without the rendering of any mutual service; and this is enough to +summon the Early Halictus to the same way-side, even as the Herring +and the Sardine assemble in the same waters. + + +CHAPTER 14. THE HALICTI: PARTHENOGENESIS. + +The Halictus opens up another question, connected with one of life's +obscurest problems. Let us go back five-and-twenty years. I am living +at Orange. My house stands alone among the fields. On the other side +of the wall enclosing our yard, which faces due south, is a narrow +path overgrown with couch-grass. The sun beats full upon it; and the +glare reflected from the whitewash of the wall turns it into a little +tropical corner, shut off from the rude gusts of the north-west wind. + +Here the Cats come to take their afternoon nap, with their eyes half- +closed; here the children come, with Bull, the House-dog; here also +come the haymakers, at the hottest time of the day, to sit and take +their meal and whet their scythes in the shade of the plane-tree; +here the women pass up and down with their rakes, after the hay- +harvest, to glean what they can on the niggardly carpet of the shorn +meadow. It is therefore a very much frequented footpath, were it only +because of the coming and going of our household: a thoroughfare ill- +suited, one would think, to the peaceful operations of a Bee; and +nevertheless it is such a very warm and sheltered spot and the soil +is so favourable that every year I see the Cylindrical Halictus (H. +cylindricus, FAB.) hand down the site from one generation to the +next. It is true that the very matutinal, even partly nocturnal +character of the work makes the insect suffer less inconvenience from +the traffic. + +The burrows cover an extent of some ten square yards, and their +mounds, which often come near enough to touch, average a distance of +four inches at the most from one another. Their number is therefore +something like a thousand. The ground just here is very rough, +consisting of stones and dust mixed with a little mould and held +together by the closely interwoven roots of the couch-grass. But, +owing to its nature, it is thoroughly well drained, a condition +always in request among Bees and Wasps that have underground cells. + +Let us forget for a moment what the Zebra Halictus and the Early +Halictus have taught us. At the risk of repeating myself a little, I +will relate what I observed during my first investigations. The +Cylindrical Halictus works in May. Except among the social species, +such as Common Wasps, Bumble-bees, Ants and Hive-bees, it is the rule +for each insect that victuals its nests either with honey or game to +work by itself at constructing the home of its grubs. Among insects +of the same species there is often neighbourship; but their labours +are individual and not the result of co-operation. For instance, the +Cricket-hunters, the Yellow-winged Sphex, settle in gangs at the foot +of a sandstone cliff, but each digs her own burrow and would not +suffer a neighbour to come and help in piercing the home. + +In the case of the Anthophorae, an innumerable swarm takes possession +of a sun-scorched crag, each Bee digging her own gallery and +jealously excluding any of her fellows who might venture to come to +the entrance of her hole. The Three-pronged Osmia, when boring the +bramble-stalk tunnel in which her cells are to be stacked, gives a +warm reception to any Osmia that dares set foot upon her property. + +Let one of the Odyneri who make their homes in a road-side bank +mistake the door and enter her neighbour's house: she would have a +bad time of it! Let a Megachile, returning with her leafy disk in her +legs, go into the wrong basement: she would be very soon dislodged! +So with the others: each has her own home, which none of the others +has the right to enter. This is the rule, even among Bees and Wasps +established in a populous colony on a common site. Close +neighbourhood implies no sort of intimate relationship. + +Great therefore is my surprise as I watch the Cylindrical Halictus' +operations. She forms no society, in the entomological sense of the +word: there is no common family; and the general interest does not +engross the attention of the individual. Each mother occupies herself +only with her own eggs, builds cells and gathers honey only for her +own larvae, without concerning herself in any way with the upbringing +of the others' grubs. All that they have in common is the entrance- +door and the goods-passage, which ramifies in the ground and leads to +different groups of cells, each the property of one mother. Even so, +in the blocks of flats in our large towns, one door, one hall and one +staircase lead to different floors or different portions of a floor +where each family retains its isolation and its independence. + +This common right of way is extremely easy to perceive at the time +for victualling the nests. Let us direct our attention for a while to +the same entrance-aperture, opening at the top of a little mound of +earth freshly thrown up, like that accumulated by the Ants during +their works. Sooner or later we shall see the Halicti arrive with +their load of pollen, gathered on the Cichoriaceae of the +neighbourhood. + +Usually, they come up one by one; but it is not rare to see three, +four or even more appearing at the same time at the mouth of one +burrow. They perch on the top of the mound and, without hurrying in +front of one another, with no sign of jealousy, they dive down the +passage, each in her turn. We need but watch their peaceful waiting, +their tranquil dives, to recognize that this indeed is a common +passage to which each has as much right as another. + +When the soil is exploited for the first time and the shaft sunk +slowly from the outside to the inside, do several Cylindrical +Halicti, one relieving the other, take part in the work by which they +will afterwards profit equally? I do not believe it for a moment. As +the Zebra Halictus and the Early Halictus told me later, each miner +goes to work alone and makes herself a gallery which will be her +exclusive property. The common use of the passage comes presently, +when the site, tested by experience, is handed down from one +generation to another. + +A first group of cells is established, we will suppose, at the bottom +of a pit dug in virgin soil. The whole thing, cells and pit, is the +work of one insect. When the moment comes to leave the underground +dwelling, the Bees emerging from this nest will find before them an +open road, or one at most obstructed by crumbly matter, which offers +less resistance than the neighbouring soil, as yet untouched. The +exit-way will therefore be the primitive way, contrived by the mother +during the construction of the nest. All enter upon it without any +hesitation, for the cells open straight on it. All, coming and going +from the cells to the bottom of the shaft and from the shaft to the +cells, will take part in the clearing, under the stimulus of the +approaching deliverance. + +It is quite unnecessary here to presume among these underground +prisoners a concerted effort to liberate themselves more easily by +working in common: each is thinking only of herself and invariably +returns, after resting, to toil at the inevitable path, the path of +least resistance, in short the passage once dug by the mother and now +more or less blocked up. + +Among the Cylindrical Halicti, any one who wishes emerges from her +cell at her own hour, without waiting for the emergence of the +others, because the cells, grouped in small stacks, have each their +special outlet opening into the common gallery. The result of this +arrangement is that all the inhabitants of one burrow are able to +assist, each doing her share, in the clearing of the exit-shaft. When +she feels fatigued, the worker retires to her undamaged cell and +another succeeds her, impatient to get out rather than to help the +first. At last the way is clear and the Halicti emerge. They disperse +over the flowers around as long as the sun is hot; when the air +cools, they go back to the burrows to spend the night there. + +A few days pass and already the cares of egg-laying are at hand. The +galleries have never been abandoned. The Bees have come to take +refuge there on rainy or very windy days; most, if not all, have +returned every evening at sunset, each doubtless making for her own +cell, which is still intact and which is carefully impressed upon her +memory. In a word, the Cylindrical Halictus does not lead a wandering +life; she has a fixed residence. + +A necessary consequence results from these settled habits: for the +purpose of her laying, the Bee will adopt the identical burrow in +which she was born. The entrance-gallery is ready therefore. Should +it need to be carried deeper, to be pushed in new directions, the +builder has but to extend it at will. The old cells even can serve +again, if slightly restored. + +Thus resuming possession of the native burrow in view of her +offspring, the Bee, notwithstanding her instincts as a solitary +worker, achieves an attempt at social life, because there is one +entrance-door and one passage for the use of all the mothers +returning to the original domicile. There is thus a semblance of +collaboration without any real co-operation for the common weal. +Everything is reduced to a family inheritance shared equally among +the heirs. + +The number of these coheirs must soon be limited, for a too +tumultuous traffic in the corridor would delay the work. Then fresh +passages are opened inwards, often communicating with depths already +excavated, so that the ground at last is perforated in every +direction with an inextricable maze of winding tunnels. + +The digging of the cells and the piercing of new galleries take place +especially at night. A cone of fresh earth on top of the burrow bears +evidence every morning to the overnight activity. It also shows by +its volume that several navvies have taken part in the work, for it +would be impossible for a single Halictus to extract from the ground, +convey to the surface and heap up so large a stack of rubbish in so +short a time. + +At sunrise, when the fields around are still wet with dew, the +Cylindrical Halictus leaves her underground passages and starts on +her foraging. This is done without animation, perhaps because of the +morning coolness. There is no joyous excitement, no humming above the +burrows. The Bees come back again, flying low, silently and heavily, +their hind-legs yellow with pollen; they alight on the earth-cone and +at once dive down the vertical chimney. Others come up the pipe and +go off to their harvesting. + +This journeying to and fro for provisions continues until eight or +nine in the morning. Then the heat begins to grow intense and is +reflected by the wall; then also the path is once more frequented. +People pass at every moment, coming out of the house or elsewhence. +The soil is so much trodden under foot that the little mounds of +refuse surrounding each burrow soon disappear and the site loses +every sign of underground habitation. + +All day long, the Halicti remain indoors. Withdrawing to the bottom +of the galleries, they occupy themselves probably in making and +polishing the cells. Next morning, new cones of rubbish appear, the +result of the night's work, and the pollen-harvest is resumed for a +few hours; then everything ceases again. And so the work goes on, +suspended by day, renewed at night and in the morning hours, until +completely finished. + +The passages of the Cylindrical Halictus descend to a depth of some +eight inches and branch into secondary corridors, each giving access +to a set of cells. These number six or eight to each set and are +ranged side by side, parallel with their main axis, which is almost +horizontal. They are oval at the base and contracted at the neck. +Their length is nearly twenty millimetres (.78 inch.--Translator's +Note.) and their greatest width eight. (.312 inch.--Translator's +Note.) They do not consist simply of a cavity in the ground; on the +contrary, they have their own walls, so that the group can be taken +out in one piece, with a little precaution, and removed neatly from +the earth in which it is contained. + +The walls are formed of fairly delicate materials, which must have +been chosen in the coarse surrounding mass and kneaded with saliva. +The inside is carefully polished and upholstered with a thin +waterproof film. We will cut short these details concerning the +cells, which the Zebra Halictus has already shown us in greater +perfection, leave the home to itself and come to the most striking +feature in the life-history of the Halicti. + +The Cylindrical Halictus is at work in the first days of May. It is a +rule among the Hymenoptera for the males never to take part in the +fatiguing work of nest-building. To construct cells and to amass +victuals are occupations entirely foreign to their nature. This rule +seems to have no exceptions; and the Halicti conform to it like the +rest. It is therefore only to be expected that we should see no males +shooting the underground rubbish outside the galleries. That is not +their business. + +But what does astonish us, when our attention is directed to it, is +the total absence of any males in the vicinity of the burrows. +Although it is the rule that the males should be idle, it is also the +rule for these idlers to keep near the galleries in course of +construction, coming and going from door to door and hovering above +the work-yards to seize the moment at which the unfecundated females +will at last yield to their importunities. + +Now here, despite the enormous population, despite my careful and +incessant watch, it is impossible for me to distinguish a single +male. And yet the distinction between the sexes is of the simplest. +It is not necessary to take hold of the male. He can be recognized +even at a distance by his slenderer frame, by his long, narrow +abdomen, by his red sash. They might easily suggest two different +species. The female is a pale russet-brown; the male is black, with a +few red segments to his abdomen. Well, during the May building- +operations, there is not a Bee in sight clad in black, with a +slender, red-belted abdomen; in short, not a male. + +Though the males do not come to visit the environs of the burrows, +they might be elsewhere, particularly on the flowers where the +females go plundering. I did not fail to explore the fields, insect- +net in hand. My search was invariably fruitless. On the other hand, +those males, now nowhere to be found, are plentiful later, in +September, along the borders of the paths, on the close-set flowers +of the eringo. + +This singular colony, reduced exclusively to mothers, made me suspect +the existence of several generations a year, whereof one at least +must possess the other sex. I continued therefore, when the building- +who was over, to keep a daily watch on the establishment of the +Cylindrical Halictus, in order to seize the favourable moment that +would verify my suspicions. For six weeks, solitude reigned above the +burrows: not a single Halictus appeared; and the path, trodden by the +wayfarers, lost its little heaps of rubbish, the only signs of the +excavations. There was nothing outside to show that the warmth down +below was hatching populous swarms. + +July comes and already a few little mounds of fresh earth betoken +work going on underground in preparation for an exodus in the near +future. As the males, among the Hymenoptera, are generally further +advanced than the females and quit their natal cells earlier, it was +important that I should witness the first exits made, so as to dispel +the least shadow of a doubt. A violent exhumation would have a great +advantage over the natural exit: it would place the population of the +burrows immediately under my eyes, before the departure of either +sex. In this way, nothing could escape from me and I was dispensed +from a watch which, for all its attentiveness, was not to be relied +upon absolutely. I therefore resolve upon a reconnaissance with the +spade. + +I dig down to the full depth of the galleries and remove large lumps +of earth which I take in my hands and break very carefully so as to +examine all the parts that may contain cells. Halicti in the perfect +state predominate, most of them still lodged in their unbroken +chambers. Though they are not quite so numerous, there are also +plenty of pupae. I collect them of every shade of colour, from dead- +white, the sign of a recent transformation, to smoky-brown, the mark +of an approaching metamorphosis. Larvae, in small quantities, +complete the harvest. They are in the state of torpor that precedes +the appearance of the pupa. + +I prepare boxes with a bed of fresh, sifted earth to receive the +larvae and the pupae, which I lodge each in a sort of half-cell +formed by the imprint of my finger. I will await the transformation +to decide to which sex they belong. As for the perfect insects, they +are inspected, counted and at once released. + +In the very unlikely supposition that the distribution of the sexes +might vary in different parts of the colony, I make a second +excavation, at a few yards' distance from the other. It supplies me +with another collection both of perfect insects and of pupae and +larvae. + +When the metamorphosis of the laggards is completed, which does not +take many days, I proceed to take a general census. It gives me two +hundred and fifty Halicti. Well, in this number of Bees, collected in +the burrow before any have emerged, I perceive none, absolutely none +but females; or, to be mathematically accurate, I find just one male, +one alone; and he is so small and feeble that he dies without quite +succeeding in divesting himself of his nymphal bands. This solitary +male is certainly accidental. A female population of two hundred and +forty-nine Halicti implies other males than this abortion, or rather +implies none at all. I therefore eliminate him as an accident of no +value and conclude that, in the Cylindrical Halictus, the July +generation consists of females only. + +The building-operations start again in the second week of July. The +galleries are restored and lengthened; new cells are fashioned and +the old ones repaired. Follow the provisioning, the laying of the +eggs, the closing of the cells; and, before July is over, there is +solitude again. Let me also say that, during the building-period, not +a male appears in sight, a fact which adds further proof to that +already supplied by my excavations. + +With the high temperature of this time of the year, the development +of the larvae makes rapid progress: a month is sufficient for the +various stages of the metamorphosis. On the 24th of August there are +once more signs of life above the burrows of the Cylindrical +Halictus, but under very different conditions. For the first time, +both sexes are present. Males, so easily recognized by their black +livery and their slim abdomen adorned with a red ring, hover +backwards and forwards, almost level with the ground. They fuss about +from burrow to burrow. A few rare females come out for a moment and +then go in again. + +I proceed to make an excavation with my spade; I gather +indiscriminately whatever I come across. Larvae are very scarce; +pupae abound, as do perfect insects. The list of my captures amounts +to eighty males and fifty-eight females. The males, therefore, +hitherto impossible to discover, either on the flowers around or in +the neighbourhood of the burrows, could be picked up to-day by the +hundred, if I wished. They outnumber the females by about four to +three; they are also further developed, in accordance with the +general rule, for most of the backward pupae give me only females. + +Once the two sexes had appeared, I expected a third generation that +would spend the winter in the larval state and recommence in May the +annual cycle which I have just described. My anticipation proved to +be at fault. Throughout September, when the sun beats upon the +burrows, I see the males flitting in great numbers from one shaft to +the other. Sometimes a female appears, returning from the fields, but +with no pollen on her legs. She seeks her gallery, finds it, dives +down and disappears. + +The males, as though indifferent to her arrival, offer her no +welcome, do not harass her with their amorous pursuits; they continue +to visit the doors of the burrows with a winding and oscillating +flight. For two months, I follow their evolutions. If they set foot +on earth, it is to descend forthwith into some gallery that suits +them. + +It is not uncommon to see several of them on the threshold of the +same burrow. Then each awaits his turn to enter; they are as +peaceable in their relations as the females who are joint owners of a +burrow. At other times, one wants to go in as a second is coming out. +This sudden encounter produces no strife. The one leaving the hole +withdraws a little to one side to make enough room for two; the other +slips past as best he can. These peaceful meetings are all the more +striking when we consider the usual rivalry between males of the same +species. + +No rubbish-mound stands at the mouth of the shafts, showing that the +building has not been resumed; at the most, a few crumbs of earth are +heaped outside. And by whom, pray? By the males and by them alone. +The lazy sex has bethought itself of working. It turns navvy and +shoots out grains of earth that would interfere with its continual +entrances and exits. For the first time I witness a custom which no +Hymenopteron had yet shown me: I see the males haunting the interior +of the burrows with an assiduity equalling that of the mothers +employed in nest-building. + +The cause of these unwonted operations soon stands revealed. The +females seen flitting above the burrows are very rare; the majority +of the feminine population remain sequestered under ground, do not +perhaps come out once during the whole of the latter part of summer. +Those who do venture out go in again soon, empty-handed of course and +always without any amorous teasing from the males, a number of whom +are hovering above the burrows. + +On the other hand, watch as carefully as I may, I do not discover a +single act of pairing out of doors. The weddings are clandestine, +therefore, and take place under ground. This explains the males' +fussy visits to the doors of the galleries during the hottest hours +of the day, their continual descents into the depths and their +continual reappearances. They are looking for the females cloistered +in the retirement of the cells. + +A little spade-work soon turns suspicion into certainty. I unearth a +sufficient number of couples to prove to me that the sexes come +together underground. When the marriage is consummated, the red- +belted one quits the spot and goes to die outside the burrow, after +dragging from flower to flower the bit of life that remains to him. +The other shuts herself up in her cell, there to await the return of +the month of May. + +September is spent by the Halictus solely in nuptial celebrations. +Whenever the sky is fine, I witness the evolutions of the males above +the burrows, with their continual entrances and exits; should the sun +be veiled, they take refuge down the passages. The more impatient, +half-hidden in the pit, show their little black heads outside, as +though peeping for the least break in the clouds that will allow them +to pay a brief visit to the flowers round about. They also spend the +night in the burrows. In the morning, I attend their levee; I see +them put their head to the window, take a look at the weather and +then go in again until the sun beats on the encampment. + +The same mode of life is continued throughout October, but the males +become less numerous from day to day as the stormy season approaches +and fewer females remain to be wooed. By the time that the first +cold weather comes, in November, complete solitude reigns over the +burrows. I once more have recourse to the spade. I find none but +females in their cells. There is not one male left. All have +vanished, all are dead, the victims of their life of pleasure and of +the wind and rain. Thus ends the cycle of the year for the +Cylindrical Halictus. + +In February, after a hard winter, when the snow had lain on the +ground for a fortnight, I wanted once more to look into the matter of +my Halicti. I was in bed with pneumonia and at the point of death, to +all appearances. I had little or no pain, thank God, but extreme +difficulty in living. With the little lucidity left to me, being able +to do no other sort of observing, I observed myself dying; I watched +with a certain interest the gradual falling to pieces of my poor +machinery. Were it not for the terror of leaving my family, who were +still young, I would gladly have departed. The after-life must have +so many higher and fairer truths to teach us. + +My hour had not yet come. When the little lamps of thought began to +emerge, all flickering, from the dusk of unconsciousness, I wished to +take leave of the Hymenopteron, my fondest joy, and first of all of +my neighbour, the Halictus. My son Emile took the spade and went and +dug the frozen ground. Not a male was found, of course; but there +were plenty of females, numbed with the cold in their cells. + +A few were brought for me to see. Their little chambers showed no +efflorescence of rime, with which all the surrounding earth was +coated. The waterproof varnish had been wonderfully efficacious. As +for the anchorites, roused from their torpor by the warmth of the +room, they began to wander about my bed, where I followed them +vaguely with my fading eyes. + +May came, as eagerly awaited by the sick man as by the Halicti. I +left Orange for Serignan, my last stage, I expect. While I was +moving, the Bees resumed their building. I gave them a regretful +glance, for I had still much to learn in their company. I have never +since met with such a mighty colony. + +These old observations on the habits of the Cylindrical Halictus may +now be followed by a general summary which will incorporate the +recent data supplied by the Zebra Halictus and the Early Halictus. + +The females of the Cylindrical Halictus whom I unearth from November +onwards are evidently fecundated, as is proved by the assiduity of +the males during the preceding two months and most positively +confirmed by the couples discovered in the course of my excavations. +These females spend the winter in their cells, as do many of the +early-hatching melliferous insects, such as Anthophorae and Mason- +bees, who build their nests in the spring, the larvae reaching the +perfect state in the summer and yet remaining shut up in their cells +until the following May. But there is this great difference in the +case of the Cylindrical Halictus, that in the autumn the females +leave their cells for a time to receive the males under ground. The +couples pair and the males perish. Left alone, the females return to +their cells, where they spend the inclement season. + +The Zebra Halicti, studied first at Orange and then, under better +conditions, at Serignan, in my own enclosure, have not these +subterranean customs: they celebrate their weddings amid the joys of +the light, the sun and the flowers. I see the first males appear in +the middle of September, on the centauries. Generally there are +several of them courting the same bride. Now one, then another, they +swoop upon her suddenly, clasp her, leave her, seize hold of her +again. Fierce brawls decide who shall possess her. One is accepted +and the others decamp. With a swift and angular flight, they go from +flower to flower, without alighting. They hover on the wing, looking +about them, more intent on pairing than on eating. + +The Early Halictus did not supply me with any definite information, +partly through my own fault, partly through the difficulty of +excavation in a stony soil, which calls for the pick-axe rather than +the spade. I suspect her of having the nuptial customs of the +Cylindrical Halictus. + +There is another difference, which causes certain variations of +detail in these customs. In the autumn, the females of the +Cylindrical Halictus leave their burrows seldom or not at all. Those +who do go out invariably come back after a brief halt upon the +flowers. All pass the winter in the natal cells. On the other hand, +those of the Zebra Halictus move their quarters, meet the males +outside and do not return to the burrows, which my autumn excavations +always find deserted. They hibernate in the first hiding-places that +offer. + +In the spring, the females, fecundated since the autumn, come out: +the Cylindrical Halicti from their cells, the Zebra Halicti from +their various shelters, the Early Halicti apparently from their +chambers, like the first. They work at their nests in the absence of +any male, as do also the Social Wasps, whose whole brood has perished +excepting a few mothers also fecundated in the autumn. In both +cases, the assistance of the males is equally real, only it has +preceded the laying by about six months. + +So far, there is nothing new in the life of the Halicti; but here is +where the unexpected appears: in July, another generation is +produced; and this time without males. The absence of masculine +assistance is no longer a mere semblance here, due to an earlier +fecundation: it is a reality established beyond a doubt by the +continuity of my observations and by my excavations during the summer +season, before the emergence of the new Bees. At this period, a +little before July, if my spade unearth the cells of any one of my +three Halicti, the result is always females, nothing but females, +with exceedingly rare exceptions. + +True, it may be said that the second progeny is due to the mothers +who knew the males in autumn and who would be able to nidify twice a +year. The suggestion is not admissible. The Zebra Halictus confirms +what I say. She shows us the old mothers no longer leaving the home +but mounting guard at the entrance to the burrows. No harvesting- or +pottery-work is possible with these absorbing doorkeeping-functions. +Therefore there is no new family, even admitting that the mothers' +ovaries are not depleted. + +I do not know if a similar argument is valid in the case of the +Cylindrical Halictus. Has she any general survivors? As my attention +had not yet been directed on this point in the old days, when I had +the insect at my door, I have no records to go upon. For all that, I +am inclined to think that the portress of the Zebra Halictus is +unknown here. The reason of this absence would be the number of +workers at the start. + +In May, the Zebra Halictus, living by herself in her winter retreat, +founds her house alone. When her daughters succeed her, in July, she +is the only grandmother in the establishment and the post of portress +falls to her. With the Cylindrical Halictus, the conditions are +different. Here the May workers are many in the same burrow, where +they dwell in common during the winter. Supposing that they survive +when the business of the household is finished, to whom will the +office of overseer fall? Their number is so great and they are all so +full of zeal that disorder would be inevitable. But we can leave this +small matter unsettled pending further information. + +The fact remains that females, females exclusively, have come out of +the eggs laid in May. They have descendants, of that there is no room +for doubt; they procreate though there are no males in their time. +>From this generation by a single sex, there spring, two months later, +males and females. These mate; and the same order of things +recommences. + +To sum up, judging by the three species that form the subject of my +investigations, the Halicti have two generations a year: one in the +spring, issuing from the mothers who have lived through the winter +after being fecundated in the autumn; the other in the summer, the +fruit of parthenogenesis, that is to say, of reproduction by the +powers of the mother alone. Of the union of the two sexes, females +alone are born; parthenogenesis gives birth at the same time to +females and males. + +When the mother, the original genitrix, has been able once to +dispense with a coadjutor, why does she need one later? What is the +puny idler there for? He was unnecessary. Why does he become +necessary now? Shall we ever obtain a satisfactory answer to the +question? It is doubtful. However, without much hope of succeeding we +will one day consult the Gall-fly, who is better-versed than we in +the tangled problem of the sexes. + + + +INDEX. + +Alpine Odynerus. + +Amadeus' Eumenes. + +Ammophila (see also Hairy Ammophila). + +Andrena. + +Andrenoid Osmia. + +Ant. + +Anthidium (see the varieties below, Cotton-bee, Resin Bee). + +Anthidium bellicosum. + +Anthidium cingulatum (see Girdled Anthidium). + +Anthidium diadema (see Diadem Anthidium). + +Anthidium florentinum (see Florentine Anthidium). + +Anthidium Latreillii (see Latreille's Resin-bee). + +Anthidium manicatum (see Manicate Anthidium). + +Anthidium quadrilobum (see Four-lobed Resin-bee). + +Anthidium scapulare (see Scapular Anthidium). + +Anthidium septemdentatum (see Seven-pronged Resin-bee). + +Anthocopa papaveris (see Upholsterer-bee). + +Anthophora (see also Anthophora of the Walls, Hairy-footed +Anthophora, Masked Anthophora). + +Anthophora of the Walls. + +Anthophora parietina (see Anthophora of the Walls). + +Anthophora pilipes (see Hairy-footed Anthophora). + +Anthrax (see Anthrax sinuata). + +Anthrax sinuata. + +Aphis (see Plant-louse). + +Archimedes. + +Augustus, the Emperor. + +Bee. + +Beetle. + +Bembex. + +Black, Adam and Charles. + +Black Plant-louse. + +Black Psen. + +Black-tipped Leaf-cutter. + +Blue Osmia. + +Book-louse. + +Brown Snail. + +Bulimulus radiatus. + +Bumble-bee. + +Calicurgus (see Pompilus). + +Capricorn. + +Carpenter-bee. + +Cat. + +Cemonus unicolor. + +Cerambyx (see Capricorn). + +Ceratina (see also the varieties below). + +Ceratina albilabris. + +Ceratina callosa. + +Ceratina chalcites. + +Ceratina coerulea. + +Cerceris. + +Cetonia. + +Chaffinch. + +Chalicodoma (see Mason-bee). + +Chrysis flammea. + +Cockroach. + +Coelyoxis caudata. + +Coelyoxis octodentata. + +Colletes. + +Common Snail. + +Common Wasp. + +Cotton-bee (see also the varieties of Anthidium). + +Crayfish. + +Cricket. + +Crioceris merdigera (see Lily-beetle). + +Cryptus bimaculatus. + +Cryptus gyrator. + +Cylindrical Halictus. + +Darwin, Charles Robert. + +Decticus verrucivorus. + +Devillario, Henri. + +Diadem Anthidium. + +Dioxys cincta. + +Dog. + +Dragon-fly. + +Dryden, John. + +Dufour, Jean Marie Leon. + +Dung-beetle. + +Dzierzon, Johann. + +Early Halictus. + +Earth-worm. + +Earwig. + +Epeira (see Garden Spider). + +Ephialtes divinator. + +Ephialtes mediator. + +Ephippiger. + +Eumenes Amadei (see Amadeus' Eumenes). + +Euritema rubicola. + +Fabre, Emile, the author's son. + +Fabricius, Johann Christian. + +Feeble Leaf-cutter. + +Field-mouse. + +Florentine Anthidium. + +Fly (see also House-fly). + +Foenus pyrenaicus. + +Four-lobed Resin-bee. + +Franklin, Benjamin. + +Garden Snail. + +Garden Spider. + +Girdled Anthidium. + +Girdled Snail (see Brown Snail). + +Gnat. + +Golden Osmia. + +Goldfinch. + +Grasshopper (see also Great Green Grasshopper). + +Great Green Grasshopper. + +Great Peacock Moth. + +Green Grasshopper (see Ephippiger, Great Green Grasshopper). + +Green Osmia. + +Grey Lizard. + +Hairy Ammophila. + +Hairy-footed Anthophora. + +Halictus (see also the varieties below). + +Halictus cylindricus (see Cylindrical Halictus). + +Halictus malachurus (see Early Halictus). + +Halictus zebrus (see Zebra Halictus). + +Hare-footed Leaf-cutter. + +Helix algira. + +Helix aspersa (see Common Snail). + +Helix caespitum (see Garden Snail). + +Helix nemoralis. + +Helix striata. + +Heriades rubicola. + +Herring. + +Hive-bee. + +Honey-bee (see Hive-bee). + +Horned Osmia. + +House-dog (see Dog). + +House-fly. + +Kid. + +Kirby, William. + +La Fontaine, Jean de. + +Lamb. + +Languedocian Sphex. + +Lanius collurio (see Red-backed Shrike). + +La Palice, Jacques de Chabannes, Seigneur de. + +Latreille, Pierre Andre. + +Latreille's Osmia. + +Latreille's Resin-bee. + +Leaf-cutter, Leaf-cutting Bee (see Megachile). + +Leaf-insect. + +Leucopsis. + +Lily-beetle. + +Lithurgus (see also the varieties below). + +Lithurgus chrysurus. + +Lithurgus cornutus. + +Lizard (see also Grey Lizard). + +Locust. + +Locusta viridissima (see Great Green Grasshopper). + +Macmillan Co. + +"Mademoiselle Mori", author of. + +Manicate Anthidium. + +Mantis, Mantis religiosa (see Praying Mantis). + +Masked Anthophora. + +Mason-bee (see also the varieties below). + +Mason-bee of the Pebbles (see Mason-bee of the Walls). + +Mason-bee of the Sheds. + +Mason-bee of the Shrubs. + +Mason-bee of the Walls. + +May-fly. + +Meade-Waldo, Geoffrey. + +Megachile (see also the varieties below). + +Megachile albocincta (see White-girdled Leaf-cutter). + +Megachile apicalis (see Black-tipped Leaf-cutter). + +Megachile argentata (see Silvery Leaf-cutter). + +Megachile Dufourii (see Silky Leaf-cutter). + +Megachile imbecilla (see Feeble Leaf-cutter). + +Megachile lagopoda (see Hare-footed Leaf-cutter). + +Megachile sericans (see Silky Leaf-cutter). + +Melitta (see Colletes). + +Miall, Bernard. + +Midwife Toad. + +Morawitz' Osmia. + +Odynerus (see also the varieties below) + +Odynerus alpestris (see Alpine Odynerus). + +Odynerus delphinalis. + +Odynerus rubicola. + +Oil-beetle. + +Omalus auratus. + +Osmia (see also the varieties below). + +Osmia andrenoides (see Andrenoid Osmia). + +Osmia aurulenta (see Golden Osmia). + +Osmia cornuta (see Horned Osmia). + +Osmia cyanea (see Blue Osmia). + +Osmia cyanoxantha. + +Osmia detrita (see Ragged Osmia). + +Osmia Latreillii (see Latreille's Osmia). + +Osmia Morawitzi (see Morawitz' Osmia). + +Osmia parvula (see Tiny Osmia). + +Osmia rufo-hirta (see Red Osmia). + +Osmia tricornis (see Three-horned Osmia). + +Osmia tridentata (see Three-pronged Osmia). + +Osmia versicolor (see Variegated Osmia). + +Osmia viridana (see Green Osmia). + +Pelopaeus. + +Perez, Professor Jean. + +Philanthus (see Philanthus apivorus). + +Philanthus apivorus. + +Plant-louse (see also Black Plant-louse). + +Pompilus. + +Praying Mantis. + +Prosopis confusa. + +Psen atratus (see Black Psen). + +Rabelais, Francois. + +Ragged Osmia. + +Reaumur, Rene Antoine Ferchault de. + +Red-backed Shrike. + +Red-Osmia. + +Resin-bee (see also the varieties). + +Ringed Calicurgus (see Pompilus). + +Rodwell, Miss Frances. + +Rosechafer (see Cetonia). + +Sapyga (see Spotted Sapyga). + +Sardine. + +Scapular Anthidium. + +Scolia. + +Scorpion. + +Seven-pronged Resin-bee. + +Shrike (see Red-backed Shrike). + +Silky Leaf-cutter. + +Silvery Leaf-cutter. + +Snail (see also the varieties) + +Social Wasp (see Common Wasp). + +Solenius lapidarius. + +Solenius vagus. + +Sophocles. + +Sparrow. + +Spence, William. + +Sphex (see also Languedocian Sphex, Yellow-winged Sphex.) + +Spotted Sapyga. + +Stick-insect. + +Stizus. + +Tachina. + +Tachytes. + +Tarantula. + +Teixeira de Mattos, Alexander. + +Termite. + +Three-horned Osmia. + +Three-pronged Osmia. + +Tiberius, the Emperor. + +Tiny Osmia. + +Tripoxylon figulus. + +Unarmed Zonitis (see Zonitis mutica). + +Upholsterer-bee. + +Variegated Osmia. + +Virgil. + +Wasp (see also Common Wasp). + +Weaving Spider. + +Weevil. + +White-girdled Leaf-cutter. + +Wolf. + +Worm (see Earth-worm). + +Xylocopa violacea (see Carpenter-bee). + +Yellow-winged Sphex. + +Zebra Halictus. + +Zonitis mutica. + + + + + +End of Project Gutenberg Etext Bramble-Bees and Others by J. 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