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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. Henri Fabre + |