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diff --git a/44496-0.txt b/44496-0.txt new file mode 100644 index 0000000..87f5956 --- /dev/null +++ b/44496-0.txt @@ -0,0 +1,3755 @@ +*** START OF THE PROJECT GUTENBERG EBOOK 44496 *** + + The Cambridge Manuals of Science and + Literature + + SPIDERS + + + + CAMBRIDGE UNIVERSITY PRESS + London: FETTER LANE, E.C. + C. F. CLAY, MANAGER + + [Illustration] + + Edinburgh: 100, PRINCES STREET + London: WILLIAM WESLEY & SON, 28, ESSEX STREET, STRAND + Berlin: A. ASHER AND CO. + Leipzig: F. A. BROCKHAUS + New York: G. P. PUTNAM’S SONS + Bombay and Calcutta: MACMILLAN AND CO., LTD. + + _All rights reserved_ + + [Illustration: The Banana Spider, natural size, from a photograph by Mr + James Adams.] + + + + + SPIDERS + + BY + CECIL WARBURTON, M.A. + Christ’s College + Zoologist to the Royal Agricultural + Society + + Cambridge: + at the University Press + 1912 + + [Illustration] + + Cambridge: + PRINTED BY JOHN CLAY, M.A. + AT THE UNIVERSITY PRESS + + +_With the exception of the coat of arms at the foot, the design on +the title page is a reproduction of one used by the earliest known +Cambridge printer, John Siberch, 1521_ + + + + +PREFACE + + +The modest dimensions of this book are perhaps sufficient indication +that it is not intended as an aid to the collector. There are about +five hundred and fifty known species of spiders in the United Kingdom +alone, and at least an equal number of pages would be needed to +describe them. + +Our concern is with the habits and modes of life of spiders—especially +of such as are most frequently met with and most easily recognised, and +the reader, especially if he is fortunate enough to spend an occasional +holiday in southern Europe, will find little in the following pages +which he cannot verify—or disprove—by his own observations. Indeed +the hope that some of his readers may be induced to investigate on +their own account has actuated the writer throughout, and has led +him to lay considerable stress upon the methods of research and the +ingeniously devised experiments by means of which whatever knowledge we +possess has been obtained. + + + CECIL WARBURTON + + + CAMBRIDGE + _March, 1912_ + + + + +CONTENTS + + + + + CHAP. PAGE + + I. A Survey of the Field. Evidences of spider industry. + Where to look for spiders. Variety of habits 1 + + II. What is a Spider? The Arthropoda and their + divisions. Arachnida. Characteristics of a + spider. Spinnerets and their use 5 + + III. The Circular Snare. Foundation lines. The + spiral with its viscid beads. The building of + the snare. Why the spider is not caught in + its own snare 13 + + IV. The Mental Powers of Spiders. The human standpoint. + Instinct. Sight. Hearing. Smell. + Taste. Memory and “educability” 20 + + V. Trap-snares and Balloons. Variations of the + circular snare. The snare of _Hyptiotes_. + Webs of _Theridion_ and _Linyphia_. The iron + railing and its aeronauts. A race congress. + Gossamer. Geographical distribution 30 + + VI. _Agelena._ Its web. The spider and its behaviour + in captivity. The platform and its carpet. + The construction of the cocoon. Instinctive, + not intelligent 38 + + VII. Water-Spiders. Marine spiders. The fresh-water + spider. The diving bell, and how it + is filled with air. Behaviour of the male. + Winter and summer houses 47 + + VIII. Crab-Spiders.—Mimicry. The appearance of + crab-spiders. Their haunts. Protective + coloration and resemblance. Habits correlated + with structure. Probable origin of + “mimicry” 52 + + IX. Wolf-Spiders. General habits. Semi-aquatic + species. Nomads and settlers. Structure. + Eyes. _Lycosa picta._ A colony in full swing. + The burrow. Egg-bags. Recognition of + cocoons. Want of discrimination. The + Tarantula. Its haunts and habits. The + death-stroke. The burrow and its parapet. + Sunning the cocoon. Carrying the young. + Poisonous properties 58 + + X. Jumping Spiders. The Zebra Spider. Its structure. + Its wonderful eyes. Hunting its prey. + The use of the drag-line. Sight in jumping + spiders. Love dances. Sham-fights. A + remarkable piece of research 76 + + XI. Theraphosid Spiders. Sub-division of the Order. + Mandibles. _Atypus_ and its nest. Its habits. + Aviculariidae. A giant spider. Trap-door + nests. Method of burrowing. “Bird-eaters,” + and their habits. _Dugesiella._ Poor sight but + remarkable sense of touch. _Psalmopoeus_ + in captivity 87 + + XII. Stridulation. How sound is produced in Arthropoda. + Its purposes. Popular mistakes. + Spines and Keys. The purring spider 105 + + XIII. The Spinning Apparatus. Spinnerets. Their + mobility. Spools and spigots. Glands. Arrangement + in _Epeira_. No interweaving of lines. Functions + of glands. Spinning operations. + The Cribellum. The feet of spiders 110 + + XIV. The Enemies of Spiders. Cannibalism. Egg + parasites. Moulting. Starvation. Body + parasites. Solitary wasps. A gruesome fate 120 + + XV. Concluding Reflexions. The “use” of spiders. + Wide range of habits. Complexity of instincts. + The mystery of the egg. The storage of + energy. Economy in diet. Conclusion 126 + + LITERATURE 133 + + INDEX 135 + + + + + LIST OF ILLUSTRATIONS + + + _Frontispiece._ The Banana Spider. + + FIG. + + 1. A Spider, a Mite and a Harvestman 9 + + 2. The Garden-spider and its snare 15 + + 3. Stretching the viscid line 19 + + 4. Preparing for flight 35 + + 5. _Agelena_ at work 44 + + 6. A Crab-spider 53 + + 7. Wolf-spiders 64 + + 8. A Jumping Spider 77 + + 9. The eyes of a Jumping Spider 78 + + 10. The love dance 84 + + 11. Stridulating “keys” 108 + + 12. Spinnerets 114 + + 13. Spiders’ feet 119 + + + + +CHAPTER I + +A SURVEY OF THE FIELD + + +There are certain days of the year when the immense wealth of spider +industry going on all around us is revealed in a way calculated to +strike even the least observant. We all know—and derive no peculiarly +pleasant thrill from the knowledge—that we can, if so minded, find +abundance of cobwebs and their occupants by visiting the cellar or the +tool-house; and probably we have all at times noticed, with a languid +interest, large circular webs on our favourite rose-bushes, with a +spider motionless in the centre. + +But some spring or autumn morning, when the night has been foggy and +the sun has only just succeeded in dispersing the mists, every bush and +hedge is seen to be draped, every square foot of lawn and meadow to be +carpeted with spiders’ silk. There has been no special activity in the +domain of these creatures, but every silken line is beaded with drops +perhaps fifty times its diameter, and what yesterday required careful +observation to detect is now visible yards away, and we realise for +once something of the prodigious activity constantly going on though +ordinarily unnoted. + +And it never entirely ceases. True hibernation, if it ever occurs, is +not the rule among spiders, and there is no time of the year when some +species may not be found at work. Beat trees or bushes over an old +umbrella, or sweep grass and herbage with a sweeping net in summer, +and you will never draw a blank—some spiders are sure to be found. In +winter such measures are profitless, but if you take the trouble to +grub among ground vegetation, or shake fallen leaves over a newspaper, +or search under stones or logs of wood you will have no difficulty in +finding spiders enough, and by no means dormant. I have even seen an +enthusiastic collector remove inches of snow and disinter rare species +from among the roots of the grass beneath! + +Spiders, then, are plentiful enough, and it is not only individuals +that are numerous but there are vastly more kinds or species than +most people dream of. The Rev. O. Pickard-Cambridge, in a book under +the modest title of _The Spiders of Dorset_ indispensable to all +British collectors, quaintly observes that most of his friends claim +acquaintance with three kinds of spiders—the garden spider, the +harvest spider and the little red spider—two of which, as it happens, +are not spiders at all. Yet the British List contains about five +hundred and fifty species, and the spiders of the world, though only +very partially investigated, already include many thousands of known +and described forms. + +In this little work we shall not at all consider the spider tribe from +the collector’s point of view. We shall concern ourselves rather with +habits and modes of life and such structural modifications as are +correlated therewith. Certain well-defined groups of spiders we shall +recognise, but specific names will interest us little. And we might do +worse than step out on such a spring morning as we have imagined and +rapidly survey the field which lies open for our investigation. + +First, then, examine a little more closely one of the garden bushes +in which the spiders have been so busy, and the chances are that +three different types of snare will be readily distinguishable. There +are sure to be some of the familiar wheel-like snares of _Epeira_, +but note also the fine-spun hammocks of _Linyphia_ with stay-lines +above and below, and the irregular labyrinths of _Theridion_, its +lines crossing and recrossing without apparent method. These are +sedentary spiders, and always to be found at home. All spiders spin +for some purpose or other, but these—or at all events _Epeira_—have +brought the art to its highest perfection. Leave them for the present +and examine a sunny wall or fence. You may chance to see a little +zebra-striped, flat-bodied spider exploring the surface and directing +its opera-glass-like eyes in all directions in search of prey. This is +one of the Attidae or jumping spiders—few and sober-coloured in this +country, but extraordinarily abundant and often extremely beautiful in +tropical regions. Pause at the iron railing before leaving the garden +and observe how the topmost bar and the knobs which crown the uprights +are alive with spiders, mostly very small, and obviously of many +different kinds, extremely busy about something that it may be worth +while to investigate later; then go on into the lane, and note, in the +banks of the hedge-rows the great sheet-webs and tubes of _Agelena_, +a near relative of the house-spider, but with a cobweb, thanks to its +situation, comparatively free from accumulations of dust and filth. + +The creatures skipping, dry-shod, on the surface of the river or +pond, though often called water-spiders, are true insects. The real +water-spider, _Argyroneta_, which, though air-breathing, spends most of +its time below the surface of the water, is not to be found everywhere, +but there are many riparian species which are semi-amphibious in their +habits and have no objection to a wetting. + +Finally, turn into the wood and look carefully on the ground, +especially where last year’s leaves are still lying. You are certain +to see a few—and may very likely see countless myriads—of sober +coloured, rapidly moving “wolf-spiders” (Lycosidae), roaming in quest +of food. No stay-at-homes, these, but rovers, trusting to speed and +agility, and not to guile, for their food supply. + +All the spiders we have observed so far are in active pursuit of their +daily business, but if we turn over stones, or logs, or look under +sheets of loose bark, we shall find others, quiescent for the moment, +but waiting for nightfall to begin their operations. + +But we have probably seen enough to show that a pretty wide field for +investigation lies immediately at hand, and that a detailed study of +what we have cursorily glanced at will occupy us so long that we shall +have little time for considering the spiders of other lands. In the +first place, however, we had better make quite sure of what is meant by +a spider. + + + + +CHAPTER II + +WHAT IS A SPIDER? + + +Not many years ago the group Insecta was held even by Zoologists +to include numberless small creatures—centipedes, spiders, mites, +etc.—which further study has shown to present essential differences +of structure, and in popular language any fairly minute animal is +still an insect, just as any insect is popularly a “fly”—or, in the +United States, a “bug.” Scientifically the use of the term Insect is +now much restricted, though still extensive enough in all conscience, +since it includes many more than a quarter of a million known species. +Zoologists recognise a large group of animals characterised by having +no internal skeleton but a more or less firm external coating of a +peculiar substance called _chitin_, often strengthened by calcareous +deposits, which necessitates the presence of joints in their bodies, +and especially in their limbs if they are to move freely, just as +medieval suits of armour required to be jointed. These are the +Arthropoda. One subdivision of this group consists of aquatic animals, +breathing by gills, and known as Crustacea. Crabs, lobsters, shrimps +and “water-fleas” are familiar examples, and with the exception of the +so-called land-crabs the only Crustaceans habitually found on land are +wood-lice. + +The other Arthropoda are air-breathing, and since their characteristic +breathing organs are branching tubes known as _tracheae_, the term +Tracheata is sometimes used to include them all. They fall naturally +into three divisions, the Myriapoda, the Insecta and the Arachnida, and +it is in this last-named division that we shall find the spiders. + +The Myriapoda are the centipedes and millipedes, and having said this +we may dismiss them, for insects and arachnids are strictly limited as +to legs; and no myriapod can ever be mistaken for a spider. + +The Arachnida are so varied in structure that it is not easy to give +characteristics common to them all, and to any general statement there +are bound to be exceptions, but for practical purposes it may be said +that while an insect, when mature, has only six legs, and a pair of +feelers or antennae of quite different structure, Arachnids have +normally eight legs, and their feeling organs are not antennae but +leg-like “pedipalps.” + +Most insects are distinguishable at once by the possession of wings, +which are never found among the Arachnida, and they generally undergo +a marked transformation or metamorphosis in their progress from the +egg to maturity, taking on at first the form of a caterpillar or grub +and then that of a chrysalis; but as there are many wingless insects +and many in which the metamorphosis is very slight, the test supplied +by these characteristics is only of partial application, and we shall +do better to rely on the number of legs, and the nature of the feeling +organs. If, therefore, we find a small wingless animal with eight legs +and a pair of feelers which are not thread-like but much of the same +character as the legs, though not used for locomotion, we may be sure +that we are concerned with an Arachnid. + +But is it a spider? + +Now some groups of the Arachnida may be put out of court at once +as having an appearance so characteristic that no confusion is +possible. Such are the Scorpions, and the minute Chernetidea or “False +Scorpions,” but this cannot be said of the Phalangidea or “harvestmen” +or of the Acarina or “Mites,” members of which groups not only may be, +but frequently are popularly taken for spiders. In fact the Phalangidea +are very commonly spoken of as “harvest spiders” and the “red spider” +is a mite. A very brief inspection, however, with a pocket lens will +settle the matter without the least difficulty. + +A spider’s body consists of two parts, a cephalothorax (head + thorax) +and an abdomen. There is a waist, but no neck. The eight legs are +attached to the cephalothorax, and the abdomen is not segmented or +ringed like that of an insect, but entire, and bears at its extremity +or on its under surface a little group of spinnerets or finger-like +projections from which the spider’s silk proceeds. For the moment these +three characteristics will suffice—the “waist” behind the leg-bearing +portion of the body, the unsegmented, legless, abdomen, and the +spinnerets (fig. 1 _B_). A harvestman, for instance, lacks the waist, +and its abdomen is segmented. Mites are of very varied form and in +some the body is more or less divided into two portions, but at least +two pairs of legs will be found to be attached to the hinder portion; +and neither harvestmen nor mites possess the spinnerets which are +the most striking characteristic of the spider; some mites—like the +“red spider”—can spin, but the mechanism by which that operation is +performed is of quite a different nature. + +[Illustration: Fig. 1. _A_, a Mite; _B_, a Spider; _C_, a Phalangid.] + +Having, then, very readily determined our specimen to be a true spider, +we may as well use it to note some further structural points the +detailed examination of which may be deferred till we have considered +their functions. Note the jaws or _chelicerae_, consisting of a stout +basal part and a fang which, when not in use, is shut down like the +blade of a knife; note the pedipalps or feelers, exactly like small +legs, but showing by their action that their function is sensory and +not locomotor. If they are knobbed at the end, the specimen is a male, +otherwise it is a female or as yet immature. Look closely at the front +part of the cephalothorax, and several eyes will be visible—probably +eight. They are not compound—divided into innumerable facets, like +those of insects—but simple and smooth, though to make sure of this +the use of a microscope would be necessary. Finally, obtain a view of +the under surface of the abdomen, and note in front, on either side of +the middle line, two semilunar patches of a lighter colour. These are +the “lung-books,”—special breathing organs peculiar to these animals; +two is the usual number, though certain spiders possess a second pair +behind the first. + +But the spinning mammillae or spinnerets are still more characteristic +and more easily seen, though, curiously enough, it is not among the +cleverest spinners that they are most conspicuous. In the family +to which most of the cellar spiders belong (Agelenidae) and in the +elongate brown or mouse-coloured spiders found lurking under stones +(Drassidae) they are visible as little finger-like projections at the +posterior end of the abdomen, but if we have taken our specimen from a +circular web (Epeiridae) we shall have to look for them more closely. +In these spiders they are beneath the abdomen near its termination, +and are not visible from above. Moreover when at rest their tips are +applied together so that they form a small rosette in surface-view, or, +in profile, a slight cone. + +The best way to capture a spider for examination is to induce it to +run up into a small glass specimen tube—for spiders readily part with +their legs if handled roughly—and if we have adopted this method we +shall see the spinnerets in use as the animal crawls about the tube. It +will not move without first attaching a silken cable to the glass, and +this cable lengthens as the spider progresses, so that before long the +interior of the tube will be a network of silken threads, and its sides +will be flecked with little white specks where the threads have been +re-attached for a new departure; and by observing closely we shall be +able to note the extreme mobility of the spinnerets in action. + +All spiders spin, but it is by no means all spiders that make snares +for the purpose of catching prey. The fundamental purpose of the +spinning organs seems to be to connect the spider with its point of +departure. The jumping spiders (Attidae) make no snare, but this +“drag-line” as it has been called comes in very useful when stalking +prey on the vertical surface of a wall, when a miscalculation at the +moment of pouncing upon it would entail a considerable fall were it not +for such an anchorage. It can hardly be doubted—though of course it is +incapable of proof—that all the more complicated spinning operations +originated in this universal spider habit, but all known spiders have +learnt to apply their power of making silk to other purposes. If they +do not make snares they at least spin “cocoons” for the protection of +their eggs, and if they have a definite home from which they emerge +to seek food, such a retreat is always more or less lined with silk. +It is clear that a spider cocoon is quite different from that of an +insect; it encloses the eggs and is manufactured by the mother, whereas +among the insects the larva makes the cocoon for the protection of the +pupa or chrysalis into which it is about to turn. However far from +exhaustive the foregoing study of spider structure may be it will +suffice for our purposes, at least for the present, and we may proceed +at once to an investigation of one of the most remarkable achievements +in the way of spinning—the familiar circular snare or wheel-web of the +garden spider. + + + + +CHAPTER III + +THE CIRCULAR SNARE + + +Select the most perfect circular snare at hand, and examine it +attentively. In the autumn, when the large garden-spider, _Epeira +diademata_ (fig. 2 _A_), is mature, it will probably be easy to find +such a snare a foot or more in diameter. It is stretched within an +irregular frame of _foundation lines_ of extra thickness and strength, +and consists of a large number of radii or spokes connected by what +appear to be a series of concentric circles, in reality a continuous +spiral, like the hair-spring of a watch. The central portion is +different from the rest of the wheel. Probably in the very centre +there is a vacant space and round this a hub, consisting of a spiral +line different in appearance from that of the main spiral. It does +not leave a radius exactly at the point where it strikes it, and the +rather zig-zag effect has caused it to be known as the “notched zone.” +Touch the web and it adheres to the finger, but all its lines are +not adhesive. Test this with some fine-pointed implement, and the +foundation lines, the radii and the notched zone will give negative +results; the spiral line alone is viscid, and its viscidity is due +to the presence of thousands of little beads of gummy matter strung +on a thin elastic thread. The vast number and uniformity of these +beads—estimated at 120,000 on a large web—excited the wonder and +admiration of naturalists until it was proved that they were not +deposited by the spider as beads at all, but as a uniform coating of +viscid matter which subsequently arranged itself into equidistant +globules easily explicable by the physicist. Indeed precisely the same +phenomenon is seen on a dew-laden web, where similar but very much +larger beads of water decorate all the lines. + +From the hub of the wheel we shall very likely notice a rather stout +cable diverging from the plane of the snare and leading to a nest of +leaves spun together. Here the spider is to be found when not on duty +in the centre of the wheel, and here it constructs its egg-cocoons. + +This, then, is the complete circular snare, but we shall understand it +much better if we watch the spider at work in its construction. + +[Illustration: Fig. 2. _A_, the Garden Spider. _B_, diagram of a sector +of the snare. _f_, foundation line; _r_, radius; _v.s_, viscid spiral; +_n.z_, notched zone; _h_, hub.] + +The first business of the spider is to lay down the foundation lines. +Any sort of trapezium—or even a triangle if large enough—in a more +or less vertical plane will suffice, and under some circumstances +the operation is simple enough. The spider attaches a line at the +point of departure and crawls along, spinning as it goes and holding +up the newly-spun thread by the claws of one of its hind feet, till +it reaches a suitable spot for its farthest limit. It then hauls in +the slack and makes it fast. It will probably return along the line +thus laid down—still spinning—to the starting point, thus doubling +the strength of the cable, and indeed a large spider will often repeat +this operation several times. Now the upper boundary of the future web +is secured. It is next necessary to find points of attachment for the +lower boundary, and the spider either drops or climbs down—always +carrying a line—from one of the ends of the upper line till it reaches +a spot suitable for its purpose, and the previous performance is +repeated. If there is any difficulty about a fourth attachment it is +always open to the spider to climb back along the two lines already +laid down, and by carrying a loose line with it, to secure at all +events a triangular frame-work. This frame-work, whether trapezoid +or triangular, will be reinforced several times and made thoroughly +trustworthy before the work of making the actual snare is proceeded +with. + +Now the foregoing operation is obviously perfectly simple in certain +cases, as, for instance when a spider has chosen lattice work, or the +mouth of an empty barrel as its “pitch,” but snares may easily be +found in situations where such a mode of procedure seems impossible. +In a pine forest, for example, one may see huge webs stretched at a +great height from the ground between boles ten feet apart; or one may +find such a snare spread across a stream at a spot where the trees on +either side do not intermingle their boughs. How in such cases does the +spider accomplish its purpose? + +There is little doubt that, wherever practicable, the spider walks +round, sometimes crawling quite an astounding distance, but that it can +at need, resort to another method, is easily proved by a very simple +experiment in the house. Fill any vessel—a basin or a bath—with water +and arrange an upright post in the middle, placing a spider upon it. +If the air in the room is absolutely still the captive is powerless to +escape, but if draughts are present it will sooner or later disappear; +and it accomplishes this feat by emitting a thread which, caught by the +air-current, is drawn out from its spinnerets till it by and by becomes +entangled in the surrounding furniture. This power of emitting silk to +some little distance and allowing the wind to draw it out is, as we +shall see, frequently exercised in the early life of many spiders. + +The foundation lines which may thus have given the spider great trouble +to secure, are of extreme importance to it, and may serve for several +snares in succession. There is little hesitation or delay about the +subsequent operations. The spokes of the wheel are readily formed by +carrying lines across to opposite points of the frame-work and uniting +them where they intersect. They are laid down in no special order, but +more or less alternation is generally noticeable—apparently for the +purpose of keeping the tension equally balanced—and the spider will +occasionally desist in order to go and brace up the frame-work with +additional stays, which generally have the effect of converting it to a +polygon. + +Before long the requisite number of fairly equidistant “spokes” or +radii are visible, and then the spider, starting from the centre, +rapidly spins a spiral thread consisting of a few coils only, to the +circumference, stepping from spoke to spoke. This is only a temporary +scaffolding and will not be suffered to remain in the completed snare. +If the structure is touched at this stage of the operations it does not +adhere to the finger; the viscid spiral remains to be laid down. Though +it does not hesitate for a moment, the spider now works with a peculiar +deliberation, but the operation will be much better understood by +actual observation than by any amount of description, and we shall only +recommend the reader to note that the new spiral is exceedingly elastic +and that at the moment of its attachment to a spoke it is stretched +and let go like the string of a bow. The spider seems carefully to +avoid treading on it as it proceeds, utilising the non-viscid spiral +scaffolding already described. + +[Illustration: Fig. 3. Stretching the viscid spiral.] + +A little attention to the centre of the wheel, and the snare is +complete. Some species of _Epeira_ entirely remove the centre, leaving +a circular empty space, while others fill it with an irregular network +of threads. + +How does the garden spider avoid getting caught in its own web? We have +shown that there are many lines which are not viscid, and no doubt +these are utilised as far as possible, but it can hardly happen that +the spider never touches adhesive portions of the web with legs or body. + +Possibly some explanation is furnished by an ingenious experiment +which Fabre performed. He found that a glass rod, lightly smeared with +oil, did not adhere to the viscid spiral; neither did a leg freshly +taken from a garden-spider unless allowed to remain in contact for +a considerable time. When, however, this leg had been washed with +bisulphide of carbon, which dissolves any kind of oily substance, it +adhered at once. It would seem likely, therefore, that the legs and +body of the spider itself are protected by some oily exudation from any +danger of adherence to its own lines. + + + + +CHAPTER IV + +MENTAL POWERS OF SPIDERS + + +Before leaving the garden-spider let us undertake some little +investigation of its mental powers—if it possesses any. The commonest +mistake with regard to all animals is to interpret their actions +from the human standpoint, and to credit them with emotions and +with deliberate forethought of which there is in reality no proof +whatever. The power to spin such a complicated snare as we have just +described predisposes us to attribute a high order of intelligence to +a creature capable of such an achievement, and when it “shams death” +on being disturbed we immediately pronounce it “cunning.” The wildest +conclusions are sometimes arrived at. One author, for instance, states +that he has seen an Attid spider “instructing its young ones how to +hunt” and adds that “whenever an old one missed its leap, it would +run from the place and hide itself in some crevice as if ashamed +of its mismanagement.” Such inferences, of course, were entirely +unwarranted from the facts observed. Now the fact that a newly-hatched +garden-spider can make a complete snare without ever having seen the +operation performed immediately relegates that action to the realm of +instinct,—not less wonderful than intelligence perhaps, but certainly +quite distinct from it. With the much discussed origin of instinct we +are not here concerned, but a pure instinct differs from intelligence +in this: that it is due to inherited nervous mechanism and results in +actions the object of which may be quite unknown to the actors. There +is no conscious adaptation of means to an end. When a young spider +spins a web there is not only no evidence that it does so with the +deliberate purpose of catching flies, but many known facts go to prove +that it performs the feat, “because it feels as if it must,” and is +quite ignorant of the purpose to be subserved. + +It is no doubt quite beyond our power to ascertain accurately the +mental condition of a spider, but it is perfectly easy to make a few +illuminating experiments on two points which have a very decided +bearing on intelligence:—the development of the senses, and the degree +of what has been called _educability_, or the power of learning from +experience. To what extent can the spider see, hear, smell, feel, +taste? How far is it capable of varying its action as the result of +experience? The senses, as far as we know, are the principal—if not +the only—avenues by which external impressions can reach the seat of +intelligence, and there is no surer indication of the intelligence of +an animal than the degree to which it is susceptible of education. +Probably most readers know the immortal story of the pike cited by +Darwin in the _Descent of Man_. The pike was in an aquarium, separated +by a sheet of glass from a tank in which were numerous small fish. +Not till three months had expired did the pike cease to dash itself +against the glass partition in its attempts to seize the fish in +the neighbouring tank. It then desisted and had evidently learnt +something—but what? After three months, the glass partition was +removed, but the pike refused to attack those particular fish, though +it immediately seized any new specimens introduced to the tank. All +that it had apparently learnt was that an attack on a particular fish +resulted in a violent blow on the nose. Some degree of intelligence +must be conceded to the pike, but it can hardly be considered of a high +order. + +Now the garden-spider possesses eight eyes, and might be expected +to see fairly well, but the experimenter will very soon come to the +conclusion that the habitual use it makes of them—at all events in +day-light—is very slight. Touch a web with a vibrating tuning-fork +and the spider will rush to the spot and investigate the instrument +with its fore-legs before distinguishing it from a fly. Remember, +however, that this is only true of what are sometimes called sedentary +spiders; species which hunt their prey have much better vision. Yet +even among sedentary spiders the power of sight is not negligible, for +a most trustworthy observer states that he has several times seen _Meta +segmentata_, a very common small Epeirid, drop from its web to secure +an insect on the ground beneath, and return with it by way of the drop +line, and the same action has been observed in the case of _Theridion_, +which spins an irregular snare. + +There are peculiar difficulties attending experiments on the subject +of hearing. An absolutely deaf person may be aware of the sounding +of a deep organ note through the sense of feeling, and a well-known +experimenter was on the point of drawing interesting conclusions from +the behaviour of a spider in response to the notes of a flute, when +he found that precisely the same results were obtained by a soundless +puff of air. It seems hardly possible to make sure, in the case of a +spider in a snare, that the sound vibrations are not _felt_, apart from +any sense of hearing, and it is a remarkable fact that it is only the +snare-spinning spiders that make any response to sounds:—free-roving +spiders are apparently quite deaf. + +In experimenting with sound we must take two precautions: the +instrument used must not necessitate any marked action which may be +visible to the spider, nor must it give rise to palpable air-currents. +These requirements are best met by a tuning-fork of not too low a +pitch. We cannot _feel_ the air vibrations emanating from it, but +can only perceive them by the ear, but we have no proof that the +spider’s sense of touch ceases precisely at the same point as our own. +However, no better instrument for experiment seems to be available, so +we take a tuning-fork, and approach it cautiously—in the quiescent +state—towards the spider, stationed, we will suppose, in the centre +of its snare. No notice is taken, and we carefully withdraw it, set +it vibrating, and approach it again in the same manner. There is now +generally a response, the spider raising its front legs and extending +them in the direction of the fork, or, if the sound is loud, dropping +suddenly by a thread and remaining suspended some inches below the +snare. The experiment should be repeated several times with the fork +sometimes still, sometimes vibrating, and the conclusion arrived at +will be that the spider is aware of the vibrating fork—but by which +sense? It is noteworthy that a fork giving a low note is always most +effective. + +Now here is a very remarkable fact. In two widely different groups of +spiders—the Theraphosidae or so called “bird-eating spiders” and the +Theridiidae—there are species with a stridulating or sound-making +apparatus, and we should hardly expect a deaf creature to evolve an +elaborate mechanism for the production of sound. This is a matter, +however, that we shall discuss later. + +No amount of research has succeeded in localising the sense of hearing +in spiders, supposing it to exist. The creature may lose any of its +five pairs of limbs (four pairs of legs and one pair of pedipalps) +without alteration in its response to sound. If the front legs +are missing the second pair are raised when the vibrating fork is +approached. + +It is fairly easy to test the sense of smell in these creatures, the +only necessary precaution being that no acid or pungent substances +capable of having an irritating effect on the skin, such as vinegar or +ammonia, must be employed. Such perfumes as lavender or heliotrope +are free from this defect. Take a clean glass rod and present it to +the spider as before, and no notice is taken. Now dip it in oil of +lavender, allow it to dry, and present it again. Most spiders respond +to such a test, Epeirids generally raising the abdomen, and rubbing one +or other of the legs against the jaws, while jumping spiders generally +raise the head and back away from the rod. Different essences produce +different effects, but there is seldom any doubt that the creature is +aware of their presence; it is not deficient in the sense of smell, but +its localisation has hitherto baffled research. + +The sense of taste does not seem to have been made the subject of any +definite experiments among spiders, though such experiments might well +lead to interesting conclusions, and the reader might do worse than +undertake some on his own account. It would be easy, for instance, +to supply a garden-spider with various insects which are generally +rejected by other insectivorous animals, and to note its behaviour. It +might refuse to have anything to do with them, or it might sample them +and turn away in disgust. In the first case the explanation might be +that it was warned of their probably evil taste by their coloration +or smell, but in any case here is an interesting little field for +research. It is the general belief among arachnologists that the sense +of taste is well developed among spiders, and it is highly improbable +that a sense so necessary for the discrimination of suitable food +should be lacking in animals with so respectable a sensory equipment. + +There is no doubt at all that the sense of touch is extremely well +developed in spiders, especially perhaps, in the sedentary groups, and +it is probable that, under ordinary circumstances, the garden-spider +works almost entirely by its guidance. Whether in the centre of the +web or in its retreat under a neighbouring leaf it is in direct +communication with every part of its snare by silken lines, and the +least disturbance usually suffices to bring it to the spot; and then, +as we have said, it will generally touch the disturbing object, however +unpromising in appearance, before deciding on its line of action. There +is little doubt that many of the numerous hairs and bristles with which +its limbs are furnished are distinctly sensory in function. + +So much, then, as to the senses of spiders; but what about their +“educability”—their power of learning from experience? Here is +evidently a wide subject, and a difficult one full of pit-falls for +the unwary, but we may nevertheless draw some inferences from the +quite elementary experiments on the senses which have been outlined +above. A spider drops on account of the sounding of the tuning-fork in +its neighbourhood; can it be educated to take no notice of the sound +after repeatedly finding that no evil consequences follow? It will +perhaps be most instructive to give in a condensed form the results +of an actual experiment selected from many performed by two American +arachnologists, George and Elizabeth Peckham, whose researches have +thrown more light than any others upon the mental equipment of spiders. +They had an individual of the small Epeirid species _Cyclosa conica_ +under observation for a month, and tested it almost daily with the +tuning-fork. At the sound of the fork the spider would drop; when +it had recovered itself and returned to the snare the fork would be +sounded again, and so on. Now on July 20 the spider fell nine times +successively—the last three times only an inch or two—and then +took no further notice of the vibrating fork. On subsequent days, +until August 5, she fell either five, six or seven times, except on +two occasions when a day’s test had been omitted, and then eleven +successive falls occurred before the spider ceased to respond. On +August 5 she seemed startled at the sound but did not fall, though the +fork was sounded nine times. During the remainder of the experiment she +generally remained perfectly indifferent to the fork, though on one or +two occasions she partially forgot her lesson and dropped a very short +distance, immediately recovering herself. + +Observe that the basis of educability is memory. For a fortnight, in +the case of this particular spider, the lesson learnt on one day +seemed to be entirely forgotten the next morning, but thereafter a +definite change of habit seemed to result. This does not appear a very +great intellectual achievement, but it is by no means despicable, +for it must be borne in mind that the habit of dropping when alarmed +is almost the only means of defence such a spider possesses, and the +instinct which prompts it must be very strongly ingrained. In the +words of the experimenters—“Taking this into consideration, it seems +remarkable that one of them should so soon have learned the sound of +the vibrating fork, and should have modified her action accordingly.” + +This single experiment has been here described in some detail largely +for the purpose of impressing the reader with the importance of +reducing the problem to its simplest terms before any inferences are +drawn, and it may well act as a model for any which he may be inclined +to undertake on his own account. The more complicated the action, +the more likely is the experimenter to read into it motives and +mental operations which exist only in his own imagination, and with +this warning we must take leave of a subject which might tempt us to +encroach too much on an allotted space. + + + + +CHAPTER V + +TRAP-SNARES AND BALLOONS + + +There are some interesting variants of the circular snare spun by some +exotic Epeirids. One North American species spins it in a horizontal +position and then raises the centre, and, by an elaborate system of +stay lines from above, converts it into a very accurately shaped dome. +A whole group of orb-weavers habitually decorate a sector of the snare +with bands of flocculent silk, the object of which for a long time +puzzled arachnologists, till it was observed that the spider drew upon +this reserve supply of material to wrap up particularly obstreperous +insects. It is not unusual for a spider of one of the common species to +remove a whole sector of the snare, and by stretching a line from the +centre to a place of retreat along the gap thus formed, to provide an +unencumbered avenue between its home and its post when on duty. For it +must not be forgotten that a spider has to walk warily on its own web, +and must avoid, as far as possible, treading on the adhesive lines, or +delay and damage to the structure are sure to ensue. + +As a rule the circular snares of the different British species are of +a very uniform pattern, differing chiefly in the degree of neatness +with which they are constructed, and in certain minor details of the +“hub,” but we have one spider, _Hyptiotes paradoxus_—an exceedingly +rare species, scarcely ever seen beyond the limits of the New +Forest—which makes such a strange snare that it seems a pity to omit +all mention of it. It consists of a sector—about one sixth of the full +circle—comprising about four radii with cross lines. From the point +where the radii meet, a “trap-line” connects the sector to another +point of attachment; on, or rather under, this trap-line, the spider +takes up its position, hauling it in so as to tighten the web and to +leave a slack portion of the line between the points where it holds +on by its front and hind legs. When an insect impinges on the web and +causes it to tremble, the spider immediately lets go with its fore +legs, and the consequent vibration of the web helps to entangle its +prey. + +The circular snare is the highest form of spinning work attained by +spiders, and there is little temptation to expend much time in studying +the cruder structures that meet the eye everywhere, but two other types +are worth a brief notice. Examine any garden bush—particularly a +holly bush, of which the rather rigid leaves provide excellent points +of support—and you will find numberless small webs made without any +discoverable method, the lines crossing one another at random in all +directions. These are the snares of some species of _Theridion_, and if +the webs lack interest the spiders themselves are worth looking at, for +they are nearly always quite prettily ornamented. + +The other common type of snare is that of _Linyphia_. It is larger and +of more definite design, consisting of a finely-spun hammock stretched +horizontally, and surmounted by a labyrinth of irregular lines. Flies +entangled in the labyrinth fall upon the hammock in their struggles to +escape, and the spider is at hand—always on the under surface of the +hammock—to ensure their capture. + +Having noted these three common types of snare, let us leave the garden +and choose a new field for our observations. + +If it is an absolutely calm sunny October morning it will be a suitable +occasion for visiting an iron railing, the “knobbier” the better. Early +summer will do, but late autumn is generally more fruitful. Almost +any railing will serve, but the most satisfactory kind is one with +the uprights surmounted by round knobs, and not by spikes. We see at +once that the knobs, and the upper rail are glistening with silken +lines; many spiders have obviously been at work there. Lines streak +the top-rail in all directions, stretch from knob to rail, or from +knob to knob if not too distant, while here and there loose ends or +streamers flutter gently in the slight currents of air. And closer +inspection reveals various small objects moving among this labyrinth +of threads. Most of them are spiders, though insects, and particularly +weevils, are not wanting. No doubt the weevils know their own business, +though the writer has not been taken into their confidence, but the +spiders are the particular object of our investigation. And first of +all note that it is a veritable race-congress of spiders; the most +varied groups are represented. Wolf-spiders (Lycosidae) which under +ordinary circumstances rarely leave the ground are found in company +with crab-spiders (Thomisidae), jumping spiders (Attidae), as well as +Epeiridae and Theridiidae of which we already know something. They +have only one thing in common—they are either small species or small +and immature specimens of larger species. They seem to be scrambling +about in a meaningless sort of way, paying little or no attention to +each other—which is odd, for spiders are terrible cannibals, and as a +general thing it would be exceedingly unsafe for a small spider to rub +shoulders with a larger one of a different species. + +The majority of them are very small, more or less black, Theridiid +spiders, the “micros” of the tribe, and their proper home is among +the roots of grass and herbage. Many of these are interesting objects +for the microscope—especially if males—because of the remarkable +protuberances or turrets which rise from their heads and bear their +eyes as on a watch tower. + +These spiders are clearly not “out” for food; they have left their +ordinary beat for quite another purpose, and we shall probably not +have to wait long before discovering it. Some one of the group ceases +its apparently purposeless wandering, and, turning its head in the +direction of what slight wind there is, raises its fore-body to the +full extent of its straightened legs, and elevates its abdomen to the +utmost. Now watch closely—using a handglass if you have one—and you +will see streamers of silk proceeding from its spinnerets. They are +shot out for a short distance and then the air current draws them out +further till they often extend for several feet, though their extreme +fineness makes it almost impossible to form an accurate judgment of +their length. Meanwhile the spider has not merely been standing on its +“toes,”—it has been firmly gripping the silken lines on the railings +with its claws. Soon it feels the pull of the streaming threads, +and when the tension is sufficient it lets go with all its claws +simultaneously, vaults into the air and sails away. Sometimes a start +is made prematurely and the insufficient buoyancy of the streamers +causes the spider to descend almost at once, and a new start is made. + +[Illustration: Fig. 4. Young spider preparing for an aerial voyage.] + +This, then, is the habitual method by which new broods of spiders +distribute themselves, especially the sedentary kinds which would +otherwise soon become over crowded in the neighbourhood of the parent +nest. And we really need not have sought out a railing at all except +for its very great convenience of observation. The same thing is going +on everywhere. It largely accounts for the astonishing carpet of silk +that the dew reveals to us on lawns and meadows at such times of the +year. Young spiders have been busy from early dawn crawling over the +grass, climbing the higher blades, and setting sail, and the whole +field is covered with their lines. Railings come in handy as furnishing +an elevated starting point, but any shrub or bush will do, and young +spiders have been seen setting sail from the parent web itself. + +McCook has given some interesting notes of his own observations on +aeronautic spiders. He followed an Attid spider fifty feet till it was +carried upward out of sight in a current of air. A Lycosid disappeared +in the same way after being followed—at a run—for a hundred feet. The +largest Epeirid he ever saw taking flight was “the size of a marrowfat +pea, say one-fourth of an inch long. After having floated over a field +and above a hedge-row, it crossed a road and anchored upon the top of +a young tree.” But perhaps his most interesting observation was on the +ability of spiders to control in some measure the duration of their +flight by reefing their sails if they wish to descend, for he saw a +ballooning spider collecting some of the streamers into a ball of silk +which accumulated near its mouth as it gradually sank to earth. + +The phenomenon known as “gossamer” has puzzled people for centuries, +and English poetical literature is full of allusions to it. Chaucer +classes it with “ebbe and floud” as an unsolved riddle, and Spenser, +Quarles and Thomson all make mention of it, generally embodying the +popular belief that it somehow had its origin in dew. “Scorchèd deaw” +Spenser calls it, while Thomson’s expression is “dew evaporate.” The +phenomenon in question is the occasional appearance of vast numbers of +silken flakes which fill the air, and which in some recorded instances +extend over many square miles and to a height of several hundred feet. +Our observations will have given a clue to its origin which is entirely +attributable to spiders, and in large measure to their ballooning +habit, though no doubt reinforced by a large quantity of silk spun +for other purposes and caught up into the air by the breeze. For a +vivid account of such a shower the reader is referred to Letter LXV of +White’s _Natural History of Selborne_, and Darwin in his _Naturalist’s +Voyage_ (Chap. VIII) records a case of the “gossamer spider” descending +in multitudes on the “Beagle” when sixty miles from land. + +In the ballooning habit we have the probable explanation of the +wide distribution of certain species of spiders which seem at first +exceedingly ill adapted for covering large distances. The Huntsman +Spider, _Heteropoda venatorius_, is practically cosmopolitan in +tropical and sub-tropical regions and the usual view has been that +ships have conveyed it from port to port. McCook, however, gives +several reasons for believing that the trade winds have much more to do +with the matter, and this may well be the case, though both agencies +have doubtless been at work. + +Very likely it was not obvious to the reader why he was recommended to +select a particularly calm, sunny autumn day for his study of spider +aeronautics; a strong steady breeze might well appear more suitable for +the purpose. Yet he would find these operations at a standstill on a +windy day, and the best possible conditions are a still warm morning +after a spell of cooler weather. The lightest air-currents serve to +float the delicate silken threads, and, what is more important, the +increase of temperature causes an upward draught which rapidly carries +the spider to a useful height where it sails gently away instead of +being swept roughly over the surface of the ground. + + + + +CHAPTER VI + +AGELENA + + +Before going farther afield, let us investigate one of the spinners +of the sheet-webs that are so unpleasantly familiar in the house. We +object to them on very obvious grounds, first as evidence of neglect +and bad housewifery, and secondly as repulsive objects when covered by +accumulations of dust which their firm texture and their durability +make inevitable. + +The common house-spiders belong to the family Agelenidae. It is quite +likely that their original home was in a warmer climate where they +lived out of doors, but that was long ago, and now they uniformly +select buildings of some sort for their operations. They have, however, +even in this country, several open-air cousins, and most people know +the great sheet-web spider of the hedge-rows, though its name—_Agelena +labyrinthica_—may be new to them. Its web consists of a closely woven +wide-spreading sheet connected with a tube of even denser material, in +the mouth of which the spider may generally be seen lurking, a rather +sinister object. If a better view of the animal is desired it is only +necessary to agitate the web slightly and the spider runs forward to +investigate. It is a large species as British spiders go—about three +quarters of an inch in length—with the abdomen rather prettily marked +with oblique white streaks. + +It is very unlike our garden spider in certain points of structure; +its body is more elongate and rather rigid, with little play of action +between the cephalothorax and the abdomen; its legs are notably long, +and so are two of its spinnerets, which can be seen protruding beyond +the abdomen as we look down upon it. + +But we shall gain little information by looking at the completed +web, and our best plan is to take the animal home and observe it +in captivity. We have prepared for its reception a box about a foot +square, with a gauze top and a movable glass front. + +It is not such an easy matter to secure the spider, which can run like +a lamp-lighter, and which has a way of escape at the lower end of its +tube. The safest way is suddenly to shut off this means of retreat with +the finger and thumb of the left hand and simultaneously to present a +glass phial at the mouth of the tube; the spider runs up into it and +is taken without the risk of injury. It is never advisable to handle +spiders, not because any British species is formidable, but because +they so readily part with their limbs in order to escape, and the +chances are that only a mutilated specimen will be obtained. + +Now _Agelena_ does not seem to be a particularly engaging pet, but +it has its points. In the first place, it very quickly makes itself +at home; a short time is spent in exploring its new quarters, but it +adapts itself almost at once to its changed situation. Moreover it +is of a peaceable and domestic disposition and the male and female +live amicably together, which is far from being the case among +the Epeiridae, whose peculiar marital relations are often—quite +wrongly—attributed to the whole tribe of spiders. A male garden-spider +courts the female at the risk of his life, and it is not surprising +that he should evince great hesitation and caution in his advances. If +his attentions are unwelcome, or even if they have been accepted, he +will be promptly trussed up and eaten unless he beats a hasty retreat. +But with _Agelena_ the conjugal relations are exemplary, and harmony +reigns in the home. The question of food is certainly a difficulty, +but if insects are let loose in the cage the spider will attend to the +catching of them. In some cases raw meat has been found a satisfactory +substitute. + +After a brief exploration of the box the captive soon becomes busy, +going to and fro across its cage and attaching lines to the sides at +some height up from the floor. So fine is the work that for a long +time hardly anything is visible, and the movements of the animal are +the only clue to what is taking place. By and by it becomes evident +that a sort of skeleton platform has been spun across the box, upon +which the spider is able to walk. It is continually strengthened by +new threads, and braced by stay-lines above and below. It has been +hardly possible to follow the operations by which this has come about, +and even now we are chiefly aware of the existence of the platform +because we see the spider walking upon it; its movements seemed very +scrambling and unmethodical, but they have resulted in the foundation +of the sheet-web and its terminal tube. But now it begins to behave +quite differently, and another phase of the work has clearly begun; +it crawls about over the almost invisible foundation lines with a most +curious gait, using its long legs to sway its body from side to side, +raising and depressing its abdomen at intervals, and as this motion +continues a beautiful gauzy sheet of incredibly fine texture gradually +grows into view. What is happening is that the spider is strewing over +the foundation lines multitudinous threads from its long posterior +spinnerets, which are beset on their under surface with numbers of +hair-like spinning tubes from each of which the silk is issuing. All +day long the process goes on, and by slow degrees the web increases in +density. Indeed for days after the structure is complete the spider +spends odd moments in going over the ground again till the sheet, and +especially the tube proceeding from it to a corner of the box, are so +closely woven as to have become almost opaque, and its occupant at +length appears to be satisfied with his handiwork, and retires into the +tube to wait patiently for casual visitors. + +July is a good month in which to experiment with _Agelena_, for if the +captives include female specimens some further spinning operations of +a very complicated description may be observed. The time of egg-laying +is at hand and elaborate preparations have to be made, but if the +experimenter wishes to see the whole process he must be prepared +to sacrifice his night’s rest, for the most critical part of the +performance takes place in the small hours of the morning. We will +describe what occurred in the case of one _Agelena_. + +The approaching oviposition was heralded several hours beforehand by +the animal commencing to weave a hammock-like compartment from the roof +of the box and above the sheet-web. This chamber was about four inches +long and was constructed precisely in the same manner as the sheet, to +which it was braced by lines from various points of its under surface. +Its construction occupied the whole day previous to the laying of the +eggs, and not until half an hour before midnight was it completed. +Within this compartment, close to the roof, the spider next wove a +small sheet one inch long, working diligently in an inverted position, +ventral surface upwards. After a quarter of an hour it rested for an +equal space, apparently exhausted by its prolonged efforts. An hour +and three quarters intermittent work served to complete the sheet, +the spider varying the monotony of its sinuous walk round this small +area by occasionally walking over it and strengthening the lines which +attached its angles to the roof. + +[Illustration: Fig. 5. _Agelena_ weaving her egg-cocoon.] + +A marked change now became observable in the manner of working. The +animal abandoned its incessant to and fro motion but began to jerk its +body up towards the sheet, throwing silk strongly against it. At the +same time the posterior spinnerets were actively rubbed together and +the long posterior spinnerets separated and brought together again +with a scissor-like action. The result of this performance was to +invest the under surface of the small sheet with a coating of flossy +silk quite unlike the ordinary web in texture, the purpose of which +soon became evident, for at about a quarter past two the spider began +to deposit its eggs _upwards_, against this loose-textured silk, +aiding the egg-mass to adhere by occasional upward jerks of the +body. This occupied between five and ten minutes, and as soon as it +was accomplished the under surface of the egg-mass was covered by a +layer of flossy silk similar to that against which it was laid, the +eggs being thus entirely enveloped in a coating of soft loose-textured +material. This was next covered in by a sheet of firm texture like that +of the original web. + +It might be supposed that the work was at length finished and that +a well-earned rest might be enjoyed, but this was far from being +the case. The spider remained as active as ever though an hour or +two passed before the object of its industry was evident. All this +time it was incessantly climbing backwards and forwards between the +egg-sheet and the hammock and generally scrimmaging round in the most +unaccountable way, but it gradually became evident that the eggs were +being enclosed in a wonderful transparent box of filmy silk with the +egg-bearing sheet for its roof. By nine o’clock it was of moderate +strength and opacity, and the spider, having worked “the clock round,” +no longer laboured continuously. Days elapsed, however, before it was +entirely finished to the satisfaction of the spider, which remained all +the time in close proximity to the box and could with difficulty be +frightened away, but clung tenaciously to it when interfered with. + +Now this remarkable performance, which any reader endowed with +sufficient patience may observe for himself, gives food for thought. +The spider has never seen a cocoon constructed and has no model to +work by, and yet it performs with absolute precision all the stages, +in their proper succession, of a work which involves quite a number of +different spinning operations, nor does the absence of light by which +to work trouble it in the slightest. It seems hard to believe that this +is not a sign of high intelligence and that the spider is probably +quite unconscious of the object for which it has laboured so long and +so aptly. But how otherwise explain this curious fact? If the eggs are +removed the moment they are laid the work is continued precisely as if +they were still there. The box is laboriously built round the place +where they ought to be, and the spider refuses to budge from the empty +casket, though there is no longer any treasure to guard. + +Clearly as the egg-laying time approaches the spider feels an +irresistible blind impulse to perform in a definite order certain +complicated actions. It is like a machine actuated by an internal +spring, and in the spider’s case the internal spring is the inherited +nervous mechanism we call instinct, which urges it to actions which it +is not in the least necessary that it should understand. + + + + +CHAPTER VII + +WATER-SPIDERS + + +Here is the place to insert a short account of some near relations of +_Agelena_ which we shall certainly not meet in our walk, but of which +the mode of life is too interesting to be altogether passed over in +silence. + +We have seen that the class Crustacea (crabs, shrimps, etc.) is the +great division of the Arthropoda entirely adapted to an aquatic life, +breathing, by means of gills, the air which is dissolved in the water. +Insects and spiders are air-breathing, and properly belong to the land; +yet there are many insects which pass their early stages—often the +greater portion of their life—in the water, and some which are very +fairly at home there when adult. Such insects often have gills when +young, and are therefore at that period true water animals, like the +Crustacea. + +The Arachnida—that division of the Arthropoda to which the spiders +belong—include a few groups which permanently inhabit the sea, and +could not live on land. There are even some weird creatures called +Sea-spiders (Pycnogonids), but these do not concern us, for they are +very far removed from the true spiders which are the subject of our +investigations. + +Now the true spiders are always air-breathing, and if they venture +into the water at all they must frequently come up to the surface +to breathe, or else they must store up a reservoir of air beneath +the surface of the water if they are to avoid death by drowning. +Nevertheless some of them have been hardy enough to encroach on the +domain of the Crustacea. Not a few are able to run freely on the +surface of the water and even to dive occasionally for the purpose +of seizing one of its denizens, but the number of those which have +succeeded in really adapting themselves to aquatic life is very +limited, and is, as far as we know, restricted to two small groups, +both of them members of the Agelenidae. + +Among the coral reefs of the Indian and Pacific oceans, and also off +the southern coast of Africa there are found spiders of the genus +_Desis_ which spend almost all their time under the surface of the sea, +from which they only emerge at low tide. They construct very closely +woven tents, impermeable to sea-water, which imprison air at low tide, +generally choosing for the purpose some cavity which has been excavated +by one of the burrowing molluscs. Beyond this we really know very +little about them, and there is much difference of opinion as to the +mode in which they obtain their food. Some writers state that they only +leave their shelters at low tide to chase small crustaceans, and that +when placed in vessels containing sea water they are quite helpless +and soon drown. On the other hand one observer found that a species of +_Desis_ was quite at home in a sea-water tank, in which it swam freely +and even attacked and fed upon a small fish. Possibly different species +of the genus behave in different ways, some being more truly aquatic +than others, though it is certain that the troubled waters of a coral +sea are not a very promising field for sub-aqueous operations. We know +a great deal more of the mode of life of those Agelenids which have +taken to living in fresh water. Indeed the subject of the water-spider, +_Argyroneta aquatica_, is so hackneyed that in dealing with it we shall +probably be telling the reader much of what he knows already, but that +possibility must be risked. + +There is, then, in many of our lakes, ponds and slow-flowing rivers +with a weedy bed, a spider which has entirely taken to a water life, +and for which it is useless to search on land. It is a docile captive, +and consequently a favourite subject for transference to an aquarium, +where its habits can be observed at leisure. Its first care is to +construct beneath the water a small dome-shaped web, open below, and it +generally selects the under surface of the leaf of a water weed for the +purpose of anchorage, though a ready-made shelter is often furnished by +the empty shell of some fresh-water mollusc. Its next proceeding is to +fill this retreat with air in a very ingenious manner. + +While swimming about in the water the spider has a most striking +appearance, its abdomen almost resembling a globe of quicksilver. +This is because the body is enveloped in a bubble of air, retained +largely by the long hairs with which it is clothed. Thus it carries its +atmosphere about with it, and as often as not it swims with its back +downwards, which has the effect of bringing the bulk of the air-bubble +towards its ventral surface, where the breathing pores are situated. +Now when the dome-shaped web is ready to be filled with air the spider +rises to the surface, lifts its abdomen above it, and brings it down +with a flop, thus imprisoning an extra large air-bubble which it +embraces with its hind-legs by way of holding it more securely, and +then, swimming rapidly down by means of its other legs to the web it +discharges its load of air beneath the downwardly directed mouth of the +dome. + +By a frequent repetition of this process the dome is at length filled +and converted into a veritable diving-bell, in which the spider can +exist quite comfortably until the supply of oxygen in the imprisoned +air is exhausted and has to be renewed. From this base it issues forth +to feed upon fresh-water insects and crustaceans, sometimes even +attacking small fishes. + +The proceedings of the male _Argyroneta_ in the mating season are +very curious. He seeks out the tent of a female and sets up his own +establishment—generally somewhat smaller—close at hand, filling it +with air in the approved manner. He then builds a sort of corridor +uniting the two domes, and when this is complete he bites through +the female dome, thus uniting the two air reservoirs by means of a +connecting tube. Not seldom it happens that the female is in no mood +for dalliance, and a battle royal ensues, with disastrous results to +both domiciles and the tube that connects them. The male, however, +is in this case well able to hold his own, for he is larger than +the female, a phenomenon elsewhere unknown in the spider realm. +_Argyroneta_ lives for some years, and makes two diving-bells each +year—one near the surface in summer and one at a greater depth in +winter. It was thought at first that one was constructed especially for +receiving the eggs and the other as a habitation, but the egg-cocoon +may be found in either, for there are two broods in the course of the +year. The winter dome is of very dense silk, glossy in appearance, and +giving the effect of a uniform sheet of silky material rather than a +fabric. Moreover its mouth is closed, and the spider remains inactive +within. It is this winter domicile that is most frequently found in the +shells of molluscs. The egg-cocoon is also dome-shaped, having a convex +upper and a flat under surface. The newly hatched young inhabit their +mother’s tent for a time and then set forth in the water to seek their +living and set up establishments on their own account. + +There is only one known species of _Argyroneta_, widely distributed +in the temperate regions of Europe and Asia. The female is about +half-an-inch long, of no particular beauty out of the water, its colour +being reddish-brown, and its body and legs very hairy. There are, +however, a few New Zealand spiders rather closely allied to it and of +very similar habits. + + + + +CHAPTER VIII + +CRAB-SPIDERS. MIMICRY + + +All spiders can spin, but by no means all use that power to entrap +their prey. Many have no settled abode or resting place except perhaps +for a short time when they are rearing their young. Among these roving +tribes, there are three groups which may engage our attention for a +time—the Crab-spiders (Thomisidae), the Wolf-spiders (Lycosidae) and +the Jumping spiders (Attidae). + +Crab-spiders are seldom seen by the ordinary observer, for their +habits do not bring them prominently into notice, and many of them +are of small size. They are well named, for there is something +exceedingly crab-like in their appearance and in their actions. Their +body is generally broad and flattened, and their legs, instead of +being arranged fore and aft, like those of most spiders, extend more +or less laterally, and though they can move pretty actively in any +direction their normal method of progression is sideways. Then again, +when frightened they cramp their legs up under their bodies in a most +crab-like fashion and “sham dead.” + +[Illustration: Fig. 6. A Crab-spider (_Thomisidae_), × 3.] + +We saw some of these spiders on the iron railing, but their real haunts +are among grass and herbage or upon the trunks of trees. Some are true +rovers, hunting their prey by day and camping out wherever they happen +to find themselves at night. Their methods are without guile—except +that they approach their victims warily; their trust is in rapidity +of action and superior strength. But other crab-spiders lead a less +strenuous life; their habit is to lurk in moss, lichen, or flowers till +an insect draws near enough to be seized without any great expenditure +of energy. + +Now in the case of some of these spiders the chance of obtaining +a meal is very greatly increased by a remarkable similarity of +coloration between the spider and its usual hunting ground. The +spider’s object is to remain invisible, and concealment is obviously +more easy if its colour matches that of its environment. To a greater +or less extent this protective coloration as it is called prevails +universally:—spiders are seldom conspicuous objects among their usual +surroundings, but it is only occasionally that we meet with cases of +very remarkable colour adaptation. Two such, however, occur among +English crab-spiders. One is a species not uncommon in the south of +England, and fairly plentiful in the New Forest, where it is to be +sought among the lichen on the tree trunks, where its blue-grey body, +marked with black and white blotches makes it practically invisible +except when in motion. It rejoices in the name of _Philodromus +margaritatus_. The other case is that of the spider known as _Misumena +vatia_, which is variable in colour, some specimens being yellow and +others pink, while a variety of the species has a blood-red streak +decorating the front part of its abdomen. If it were to choose lichen +as a hunting ground there would be little chance of concealment, but +it does nothing so foolish:—it hides among the petals of flowers, +generally, but not always, among flowers more or less of its own colour. + +Now this phenomenon of resemblance is sometimes carried very much +farther than a tolerable correspondence between the colour of an +animal and its surroundings; it occasionally amounts to an apparent +imitation, in form and in behaviour as well as in colour, of some +other object, either animal or vegetable and in such cases we have +examples of what is known as Mimicry. Most people have seen remarkable +instances of this phenomenon in the “stick” and “leaf” insects of +entomological collections. There are several different ways in which +such a resemblance may be profitable to the imitator. Clearly it may +be advantageous for a weak animal to be mistaken for one much more +formidable and less likely to be attacked, or for an insect which is +really extremely good eating to resemble closely one which birds well +know to be unpalatable. Or again, if your line is to lie _perdu_ and +wait for some unwary insect to come within reach, it must be a distinct +asset to be indistinguishable from such an innocent object as a twig +or a leaf; and the same disguise may serve you if you are the possible +victim and you can make the would-be devourer believe that you are a +mere vegetable. + +It is seldom difficult to see some such possibility of gain in the +numerous well-known cases of insect mimicry. The wasp tribe—formidable +with their stings—are often “mimicked”; the unpalatable Heliconid +butterflies are “imitated” by members of edible families, and some +insects are such exact imitations of leaves that the all-devouring army +ants have been seen to run over them without discovering the imposition. + +“Mimicry” is an unfortunate term inasmuch as it seems to imply +intentional imitation; “protective resemblance” is better. It is +generally accounted for by the action of “natural selection” upon +random variations. No two members of a brood are exactly alike; slight +variations in form, size, colour, etc., are constantly occurring, and +when the variation is a useful one the animal possessing it has a +slightly better chance of surviving and rearing progeny, some of whom +will probably possess the same peculiarity, perhaps even in a more +marked degree, and will be better equipped than their neighbours in the +struggle for life. The happy possessors of such favourable variations +are thus in a sense “selected” by nature, and this selection, acting +through countless generations, is thought to be the chief agent in +bringing about the remarkable phenomenon of protective resemblance. + +The theory has, no doubt, been pushed too far; fanciful resemblances +have been detected and advantages of which there is no proof are +sometimes asserted, and moreover other possible ways of accounting for +the facts have been too much overlooked. + +But however it has come about, there is a case of “mimicry” among +crab-spiders which deserves more than a passing mention. The name +of the spider in question is _Phrynarachne decipiens_, and it was +accidentally discovered by Forbes when butterfly-hunting in Java. It +spins a white patch of silk on the upper side of a leaf on which it +places itself back-downwards, clinging to the web by means of spines on +its legs. It then folds its legs closely and lies absolutely still. In +this position the spider and web look precisely like the dropping of +some bird upon the leaf; such droppings are frequently seen, and seem +to be particularly attractive to butterflies. It was not until Forbes +tried to catch a butterfly settled on a leaf that he found that what +looked like excrement was really a spider which held the butterfly in +its grasp. Even after this experience he was again deceived by the same +species in Sumatra. + +There are several extremely ant-like spiders, and it is remarkable that +some of the imitators belong to widely different spider families:—that +is to say the resemblance has arisen independently from quite different +starting points. + +It is very noteworthy that resemblance in structure is always +accompanied by similarity of behaviour—as indeed it is bound to be +if any benefit is to accrue to the mimic. Your resemblance to a leaf +will deceive no one if you run wildly about, and your imitation of an +ant will lack verisimilitude if you adopt a slow and stately method +of progression. Ant-like spiders adopt the hurried and apparently +undecided gait of their models, and insects which look like sticks, +leaves, or inanimate objects all possess the power—and the habit—of +remaining for a long time perfectly motionless. + + + + +CHAPTER IX + +WOLF-SPIDERS + + +Of the groups of wandering spiders, which spin no snare but trust to +speed and agility for their food, the Lycosidae or wolf-spiders supply +the best subjects for study. To begin with, they are very numerous +at certain times of the year, some species absolutely swarming in +woods during May and June among the leaves which fell in the previous +autumn. During the summer months they are still in evidence, but +as winter approaches they rapidly disappear. The swift motion and +predaceous habits have earned them the name of wolf-spiders, but +though they sometimes occur in incredible numbers so that it seems +impossible to avoid treading upon them, they do not hunt in packs; each +one is entirely concerned with his own individual quarry. They are +moderate-sized or large spiders—commonly about half an inch long in +this country though there are exotic species which attain an inch and +a quarter—and in build they are very unlike the garden-spider, being +elongate, and with the abdomen nothing like so globular. + +Their habits vary considerably. One genus, appropriately named +_Pirata_, is semi-aquatic, living at the margins of rivers and ponds, +and able to run on the surface of the water, but most of the Lycosidae +prefer dry land—the dryer the better. Heaths, sandhills, bare and +stony stretches of soil, even deserts, are fertile in examples of this +group. Most of the smaller species love the sunlight, and it is often +noticeable on a bright day, when the ground seems to be alive with +wolf-spiders, that a chance cloud obscuring the sun will cause them to +disappear as if by magic. + +Some of the small Lycosids seem to be absolute wanderers, having +no home at all, but spending the night under a stone or any casual +shelter, while others dig a more or less temporary hole in the ground +into which they carry their captured prey, and in which they take +refuge on the appearance of an enemy. The large wolf-spiders have +permanent burrows from which they do not wander far and in the mouths +of which they spend most of their time, on the look out for passing +insects. + +Let us first catch one of the small wolf-spiders and examine it. +This is not a very simple operation with creatures which can run so +swiftly, but after a few attempts we induce a specimen to run up +into a glass tube held in the line of its course. We see it to be a +long-bodied spider thickly beset with hairs which entirely hide the +integument of the abdomen. Its general hue will probably be a dark +grey, and its abdomen will be decorated by a more or less distinct +pattern due, not as in the garden spider to pigments in the skin, but +to the coloration of the hairs. But look particularly at its eyes. A +pocket-lens will suffice to reveal that two of them are much larger +and much more business-like in appearance than anything _Epeira_ +had to show. These are directed forwards, being placed at the upper +angles of the perpendicular front face, so to speak, of the animal. +Below them, just above the jaws, are four small eyes in a transverse +row, and behind them at some distance, on the upper surface of the +cephalothorax, are yet another pair of moderate size. In some groups +of spiders the eyes are not only small but have an indefinite, dull, +ineffectual appearance; here they are clear-cut, glossy and convex; +sight apparently counts for something in the case of the Lycosidae. +And this is what we should expect. A sedentary spider is informed +of the whereabouts of its prey by the sense of touch, through the +trembling of the web, but a wolf-spider spins no web and is dependent +on the keenness of its vision. + +There is a very prettily marked English Lycosid which is often found on +sandhills, in situations particularly convenient for observation. Its +name is _Lycosa picta_, and it is incidentally interesting as affording +a good example of protective coloration, for the sandhill variety is +light-coloured and very inconspicuous when stationary on the sand, +while an inland variety not uncommon on the dark soil of heaths is of +a much darker hue. Carefully scrutinising the firmer sand of the dunes +on a sunny June day, I detect a number of small holes—the burrows of a +colony of these spiders—and approaching cautiously I establish myself +at full length at a distance of a yard or so on the side away from the +sun, in such an attitude that I can observe closely for a considerable +time without too much discomfort. The minutes pass and nothing +happens, but I know that the cardinal virtue of the naturalist is +patience, and I wait. Presently the dark circle of one of the burrows +is obliterated—it is filled by the sand-coloured head of the spider, +coming up to prospect. Other heads appear, and soon one spider, bolder +than the rest, emerges bodily, and remains for a minute motionless, on +the _qui vive_. Finding no cause for alarm, it presently begins moving +about stealthily, and before long several members of the colony are +busily exploring the neighbourhood. A cloud passes over the sun and all +quickly disappear into their holes, but this time without alarm, for +they come forth unhesitatingly when the sun shines again. + +It is a fascinating sight to observe these little creatures pursuing +their operations in absolute silence under my very eyes. A few stealthy +steps are taken, the body being so moved that the battery of eyes is +brought to bear upon different points of the compass; a short quick run +ensues, followed by more cautious movements. I am not fortunate enough +to see the actual running down of a quarry, but in time I note one of +the colony bringing home an insect in its jaws. So absorbed am I that I +fairly jump when a horrified human voice close at hand observes “He’s +in a fit”! I have excited the solicitude of a girls’ school which has +approached noiselessly over the sand on their afternoon promenade, and +stands gazing at me with as much fascination as I at the spiders. I +hasten to reassure them, but the spell is broken, and the séance is at +an end. Not a spider is visible. + +But I can still do one thing. Here is a good opportunity of finding +out something about the burrows of these spiders. In turf the +investigation would be difficult, but it is easy to operate in the +tolerably firm sand where the colony has established itself. + +I insert a straw into one of the burrows as a guide to the exploration, +and with a knife carefully begin to remove the sand immediately round +it. It is lined, I find, by a very delicate and slight coating of silk, +no more than sufficient to keep the sand particles of its walls from +falling down into the tube. I go down for an inch and a half or so and +find that the tube ends blindly in a sort of silk-lined pocket, but +no spider is there! This is mysterious, for I am pretty sure that my +spiders are at home. + +I go to work upon another burrow, but this time in a different way, +digging it out bodily with its surrounding sand, and placing it on +a sheet of paper, with which I am luckily provided, for a detailed +examination. I can now approach it from the side, and by carefully +removing the sand, lay bare the whole silken tube. As before there is a +straight perpendicular burrow, ending blindly, and uninhabited, but at +a point at about half-way down the tube I find a branch bending upward, +so that the whole tunnel is +Y+ shaped, and at the blind end of +this branch I find the spider. + +This observation suggests that the tunnels of some of our English +wolf-spiders may be more complex than was imagined. At present nothing +is known of their nature in the case of other species. + +A little later in the summer the appearance of a troop of wolf-spiders +has undergone a marked change; almost every individual will be found +burdened with a circular bag of eggs attached firmly to its spinnerets, +and carried about with it in all its wanderings. + +[Illustration: Fig. 7. Wolf-spiders; _A_, with egg-cocoons; _B_, with +young on its back.] + +The “cocoon” is worth examination. It is a rather flattened sphere, +with an equatorial line round it, giving the effect of two halves—an +upper and a lower. The operation of making it has very seldom been +observed, because it takes place in a closed retreat constructed for +the purpose. McCook was fortunate enough to see something of it in the +case of a captive _Lycosa_ which he kept in a glass jar partly filled +with soil. Luckily the spider dug its tunnel for cocooning purposes up +against the side of the jar, so that its interior was visible. It was +about an inch deep and fairly wide, and its aperture was closed with +silk. + +Against the perpendicular wall of soil a circular silken cushion about +three quarters of an inch in diameter was spun, and the eggs deposited +in the centre. The edges of the cushion were then gathered up and +pulled over the eggs, and the bag thus formed was finished off with an +external layer of spinning work on the two halves of the sphere, the +seam or “equator” being left thin for the exit of the young spiders. +The _Lycosa_ then attached the cocoon to its spinnerets and proceeded +to bite away the silken sheet which sealed the burrow. The whole +operation lasted about four and a half hours. + +Thenceforward, till the young are hatched, the wolf-spider never quits +her egg-bag, which she carries about on all her expeditions attached by +threads to the spinnerets. Garden-spiders die soon after laying their +eggs and never see their progeny, but here we have a case of maternal +solicitude persisting for many days, and the Peckhams seized upon it as +a good subject for investigating the subject of the memory of spiders. +If the cocoon were removed from the spinnerets, after how long an +interval would it be recognised by the mother? + +A _Pirata_ was selected for experiment. It offered great resistance +to the removal of the cocoon, seizing it with its jaws and trying to +escape with it. When it had been taken away the mother displayed great +uneasiness, searching for it in all directions. It was returned to her +after an hour and a half, when she received it eagerly and immediately +attached it in the usual position. + +From three others of the same species the cocoons were removed and +restored after thirteen, fourteen and a half, and sixteen hours +respectively. All remembered them and took them back immediately. But +twenty-four hours seemed to be the extreme limit of their memory; +after that interval two of the mothers refused to have anything to +do with their cocoons, while the third only resumed hers, slowly and +without any enthusiasm, after it had been placed before her seven +times in succession. Some other species seemed to possess a rather +longer memory, but the experimenters found no Lycosid constant in her +affection for so long a period as forty-eight hours. + +We have said that Lycosid spiders see comparatively well; yet, if +they are placed within an inch or two of their cocoons they may be +quite a long time finding them. This is very puzzling until it is +considered that its habitual position is such that the spider never +sees it. She never has seen it since its construction, and does not +in the least recognise it by sight. Spiders of other groups, where +the female remains near but detached from the cocoon, are not at the +same disadvantage, and if the cocoon is removed to a short distance +the mother will go straight to it and bring it back. The wolf-spider +only knows the _feel_ of the cocoon; she may pass close by it without +recognition, but as soon as she touches it the cocoon is immediately +resumed—if the interval of separation has not been too great. + +But is it necessary to restore to the spider her own cocoon? Will not +that of another spider serve as well? Certainly it will; a wolf-spider +will eagerly adopt the cocoon of a spider even belonging to a different +genus, if not greatly unlike her own in size. Nay, even a ball of pith +of the same size will be attached with alacrity to the spinnerets, +though if offered a choice between a cocoon and a pith ball the +spider, after some hesitation, selects the real article. One spider +even accepted a cocoon into which a leaden shot had been inserted, +making it many times its original weight. She could hardly crawl with +her new burden, but stuck to it gallantly, and when several efforts +to secure it to her spinnerets had proved ineffectual she carried +it about between her jaws and the third pair of legs. Again we find +the intelligence of the spider distinctly limited, but its powerful +instincts are equal to all ordinary requirements. Nature does not, +as a rule, play extravagant pranks, such as interchanging cocoons or +substituting for them pith balls and leaden pellets. + +The famous Tarantula is a wolf-spider, though in America, +unfortunately, the name has been quite wrongly applied to the members +of an entirely different group. Everyone has heard of its deadly +repute, and of the myth that its bite can only be cured by the wild +tarantula dance or tarantella. It is one of the large Lycosids of +southern Europe. These, as we have said, are much less nomadic than +the smaller species, but have a permanent home, from which they do not +wander far afield. They prefer waste, arid places, and their burrows +are simple cylindrical tubes with the upper portion lined by silk, the +mouth being often surmounted by a sort of rampart of particles of soil +mingled with small pieces of wood collected in the neighbourhood. The +spider lurks in the mouth of the tube where its glistening eyes can be +distinctly seen. If an insect ventures near it rushes out and secures +it; if alarmed, it retreats instantly to the bottom of the burrow. + +That most fascinating of all entomological writers, J. H. Fabre, made +some observations on a tarantula of southern France which well deserve +attention. Colonies of the spider were numerous in his neighbourhood, +and he set himself to procure some specimens. Old writers assert that +if a straw be inserted into the burrow the spider will seize it and +hold it so firmly that it may be drawn forth. Fabre found this method +exciting, but uncertain in its results. Another plan which had been +advocated was to approach warily and cut off the retreat of a spider by +plunging the blade of a knife into the soil below it and so cutting off +its retreat, but this required very rapid action, and was, moreover, +apt to be prevented by the presence of stones in the soil. He devised +a new scheme. He provided himself with a number of “bumble” bees in +narrow glass tubes—about the width of the spider burrows. Repairing +to a tarantula colony he would present the open end of the tube to +the mouth of a burrow. The liberated bee, seeing a hole in the ground +exactly suitable for its own purposes, would enter it with very little +hesitation. There would be a loud buzz and then instant silence. +Inserting a pair of forceps into the hole, Fabre would then withdraw +the bee with the spider clinging tenaciously to it. In all cases the +death of the bee was instantaneous, though the closest examination of +its dead body revealed no wound. + +Now Fabre was fresh from his wonderful studies of the habits of the +solitary wasps, which provide their young with insects stung in such +a way as to cause paralysis but not death. In their case the problem +was to secure food for their larvae which should remain fresh for +many days, an instinct taught them to solve it in the most remarkable +manner. The problem of the spider was different. It was a case of +killing instantly, or being killed; a merely wounded bee is as +formidable as one unharmed. What Fabre desired to know was this: did +the spider trust to one invariable deadly stroke in dealing with the +bee, as the solitary wasp, according to its species, had been found to +act always precisely in the same way in paralysing its victim? + +To settle this point the spider must be seen at work, and the obvious +plan seemed to be to enclose a bee and a tarantula in a glass +vessel and see what would happen. But nothing happened at all. The +spider, away from its burrow, refused to attack. The equally matched +antagonists treated each other with the greatest respect and only +evinced a desire to keep as far apart as possible. Even when placed in +the same tube both acted on the defensive, and no light was thrown on +the problem. + +But Fabre’s ingenuity was equal to the occasion. It occurred to +him that to use as a bait an insect of burrowing habits had been a +tactical error; if instead of a bumble bee some other insect, equally +formidable, but not attracted by holes in the ground, were selected for +the purpose, the spider might be induced to rush forth and reveal its +method of attack. + +A large carpenter bee—_Xylocopa_—was chosen and the mouth of +the tube containing it was presented as before to the mouth of the +tarantula tunnel. The insect showed no disposition to enter the tunnel, +but buzzed in the tube outside. Many burrows were tested before any +luck attended the investigator, but at length a spider responded. +There was a fierce rush, a clinch, and the bee was dead; the operation +was too rapid to follow, but the spider’s fangs remained where they +had struck—embedded just behind the insect’s neck. The experiment +was repeated until sufficient cases had been witnessed to establish +the fact that the tarantula dealt no random stroke but with unerring +precision and lightning rapidity plunged its fangs into the vital spot. +Fabre quaintly exclaims “J’étais ravi de ce savoir assassin; j’étais +dédommagé de mon épiderme rôti au soleil!” + +Examples of the same species of tarantula kept in captivity threw +further light of the habits of the group. These large Lycosids live for +years, and though stay-at-homes when _rangé_ so-to-speak, they are at +first wanderers on the face of the earth. They do not settle down and +burrow till the autumn just after they have attained maturity. These +young adults are only about half the size they will eventually attain, +but the burrows are enlarged at need, so that it is customary to find +tubes of two sizes—those of the newly established small females, and +those of the fully-grown females of two or more years old. + +Curiously enough, if disturbed, they entirely decline to burrow +unless it be the proper season for that operation, but remain inert +and helpless on the surface till they die. If, however, a tunnel is +provided for them, they enter it at once and adapt it to their needs. + +The legs take no part in the burrowing process, which is entirely +carried out by the jaws. With infinite labour small particles of +earth are dislodged and carried by the mandibles to be dropped at a +considerable distance from the nest. + +The parapet round the mouth of the tube is in nature usually quite +a small erection, but this seems to be due to the fact that only +a small amount of suitable material is available in the immediate +neighbourhood, and the spiders will not go far afield. In captivity, +when abundance of material was supplied, they attained a height of two +inches. Small stones, sticks, and strands of wool cut into lengths of +one inch and of various colours were placed within reach, and all were +used in building the parapet. Comparatively huge pebbles were rolled up +for a foundation, and fragments of earth and pieces of wool entirely +irrespective of colour were bound together by irregular spinning work. + +On sunny days the spiders would crouch behind the parapet with their +eyes above its level. To distant insects they paid no attention, but +if one approached within leaping distance, it was pounced upon with +unfailing accuracy. + +In due season the captives laid their eggs and enclosed them in the +regulation cocoon which they attached to their spinnerets, never +parting from them thenceforward, though considerably hampered by them +in their movements up and down the tube. But a very remarkable change +now took place in their behaviour at the mouth of the tunnel. In sunny +weather, instead of remaining, as Fabre puts it, “_accoudé_” on the +parapet, they reversed their position, raised their egg-cocoons with +their hind legs, and slowly and deliberately turned them about, so that +every part in succession should be exposed to the sun’s rays. + +We now come to a remarkable habit possessed by all the Lycosidae. +When the young are ready to leave the cocoon they find an exit at +the thinner equatorial seam, and proceed immediately to climb on to +the back of the mother, clinging firmly to her covering of hairs. +If a wanderer, she carries them thus on all her expeditions; if a +stay-at-home, they accompany her up and down her tube. They are often +dislodged—indeed, when alarmed, they scatter for the moment, but when +the peril has passed they immediately swarm up the maternal legs to +their former position. + +Now in the case of the tarantula, it is seven months before they are +able to fend for themselves. Meanwhile they eat nothing, and look on +with indifference while their mother feeds. She not only carries them +willingly, but exhibits solicitude when deprived of them, but she shows +no discrimination as to her own offspring, and is quite content with +those of another spider. The young, when brushed off, climb the legs +of the nearest female, and a spider may thus be laden with thrice her +proper load without any protest. They form a layer two or three deep, +and can then only find room by covering the whole of her back. They +nevertheless take care not to obscure her vision by covering her eyes. + +Two mother tarantulas, each with her young on her back, came into +contact, and a battle _à outrance_ took place. One was slain, but the +double brood, scattered by the conflict, on its cessation climbed on +to the back of the victor, and remained calmly in position while she +proceeded to dine in leisurely fashion on the vanquished! + +In March, seven months after hatching, the young were ready to +start life for themselves. Their first action was to climb to the +highest points attainable, whence they set sail in the manner already +described, and were borne gently away in the air. + +We can hardly leave the tarantula without saying something on the +vexed question of spider venom. All over the world there are certain +particular spiders whose bite is especially feared. Among them are +the “Tarantula” and the “Malmignate” of southern Europe, the “Vancoho” +of Madagascar, the “Katipo” of New Zealand, and the “Queue rouge” +of the West Indies. Quite an extensive literature has arisen around +the subject but its perusal leaves one not much wiser than one was +before. Circumstantial accounts of deaths from the bite of a spider +are countered by the assertions of experimenters that they have +allowed themselves to be bitten repeatedly by the same species without +suffering any inconvenience. There is at all events some basis for +the popular view in the fact that all spiders possess a poison gland +which is analogous to that of the snake inasmuch as it opens near the +tip of the fang which is plunged into the animal attacked. In the case +of the large, powerful spiders of the family Mygalidae, and perhaps +in the tarantulas the effects of the bite on higher animals are not +negligible, and clearly exceed the results of a mere puncture. A young +sparrow and a mole bitten by Fabre’s tarantula in spots by no means +vital died within a few hours. But it is a very remarkable fact that +many of the most dreaded spiders are neither large nor powerful. The +“Malmignate,” the “Vancoho,” the “Katipo,” and the “Queue rouge” are +all members of the comparatively weak-jawed Theridiidae, and their only +striking characteristic is vivid coloration, all being marked with +red spots. It is probable that their deadly powers are almost entirely +fabulous; and that they have been singled out as particularly dangerous +merely because of their conspicuous appearance. + +The smaller species are certainly harmless as far as man is concerned, +and it is even disputed whether their poison plays much part in +the ordinary slaying of insects. The very inconsistent results of +experiments may be due to some control exercised by the spider over the +output of poison. There is no proof that its ejection is automatic, +and it is quite possible that the spider is economical in its use. Or +again, in some of the cases of innocuous biting, the supply of venom +may have run short. + + + + +CHAPTER X + +JUMPING SPIDERS + + +We are not in the land of the jumping spiders or Attidae, and our few +and sober-coloured examples of the group give but a feeble idea of the +Attid fauna of tropical countries where these creatures abound and +often rival the “ruby-tail” flies in the brilliancy of their hues. + +[Illustration: Fig. 8. Salticus scenicus, female, × 4.] + +It is one of the largest groups, numbering several thousand species, +but the British list includes barely thirty, and most of these are +of rare occurrence, or at all events exceedingly unlikely to be met +with by any but the most energetic collector. Indeed it may be said +that there is only one British species which we may look forward with +tolerable confidence to finding upon some sunny wall or fence in the +summer, in whatever part of the country we may be. This is _Salticus +scenicus_, sometimes called the Zebra Spider. Though absolutely +dowdy in comparison with most of its tropical cousins, it is a not +unattractive little creature, and illustrates sufficiently well the +characteristics of its tribe. Armed with a pocket-lens, a glass tube +or two, and—more necessary still—the very largest amount of patience +we can summon, we go in quest of the zebra spider. A tarred fence is +a good hunting ground, because the spider, if present, is readily +seen, but if this is drawn blank we must have recourse to a wall, where +sharper eyesight will be required. + +[Illustration: Fig. 9. “Face” of an Attid spider, shewing the anterior +eyes and the chelicerae.] + +Our quarry is of small size, not more than a quarter of an inch long +in the body, which resembles that of the wolf-spiders in build, the +abdomen not rising above the level of the fore-body or cephalothorax. +It is thickly clothed with short hairs—black, white, and grey—so +arranged as to show oblique zebra-like stripes on either side of the +abdomen. The legs are short and robust, very different from the long +thin limbs of the garden-spider; especially strong are the fore-legs. +The head is broad and square, with a high perpendicular forehead, but +the most remarkable features are the eyes. + +On the vertical front are four splendid eyes. The wolf-spider’s eyes +were large, but these, in comparison, are immense, especially the +median pair. Their axes are directed straight in front. Four other eyes +are placed on the top of the head, far apart from each other, the +more forward pair very small, the hind pair of moderate size. In some +Attid spiders these great anterior eyes are wonderful objects under +the microscope, deep sea-green in hue and fringed with coloured hairs. +They form a veritable battery which the spider brings to bear upon the +object of its chase. Human eyes, to match them in comparative size, +would literally have to be as large as saucers! + +If we are in luck, we soon descry a _Salticus_ showing up boldly +against the black surface of the fence, and to set ourselves to watch +its antics attentively. One thing strikes us at once; it is quite at +home on a perpendicular surface—nay, on the under side of a horizontal +beam, for that matter. Now a garden-spider would have great difficulty +in maintaining itself in such a position unless well supplied with +silken lines to which to cling; evidently there is some difference +in the structure of the feet of these spiders which may be worth +investigating later on. + +Also we notice some odd tricks of movement in the jumping spider; +a curious way of exploring the surface on which it is working by a +succession of short runs alternately with periods of absolute stillness +as though on the _qui vive_; a noticeable freedom of movement between +the fore- and the hind-bodies so that its battery of eyes may be +directed to this side or that; sometimes an elevation of fore part as +though for the purpose of obtaining a wider view. + +We may have to wait long before we see it successful in the chase. It +will often patiently explore a large area, testing the surface with +its palps as it goes, without any obvious reward. It conscientiously +searches all depressions and crannies, and, sometimes remains in them +for a considerable time—perhaps to devour some minute creature which +did not call into play its special methods of attack. At last it sights +a small insect which has alighted on the fence a few inches away; we +see it turn its head in that direction and remain motionless. Soon it +begins to edge nearer in a stealthy manner, striving to approach its +prey from behind, till, with a sudden spring, it pounces on its back. +Not always is the spring successful; often the insect sees its peril +at the last moment and takes to wing. But in this case, how does the +spider avoid a fall? We see, what we had not noticed before, that it is +anchored to the fence by a silken line; indeed all the time it has been +hunting it has been trailing behind it an exceedingly fine thread of +silk which it has attached at frequent intervals to the fence, so that +it can check its fall at will in the case of accident. At the right +angle, we may see the delicate filaments glistening in the sun over the +surface of its explorations. The garden-spider entangles its prey in a +web, the wolf-spider runs it down by sheer strength and speed, but the +jumping spider stalks it like a Red Indian. + +The actions of the spider make it quite evident that its power of sight +is well developed. Mr and Mrs Peckham, whose remarkable observations +on the mating habits of jumping spiders must presently be considered, +established friendly relations with some of their captives which became +so tame as to jump on their hands and take food from their fingers. +They frequently induced them to jump from a finger of one hand to one +of the other, gradually increasing the distance up to eight inches. +They also twice observed a male chasing a female upon a table covered +with jars, books and boxes. “The female would leap rapidly from one +object to another, or would dart over the edge of a book or a box so +as to be out of sight. In this position she would remain quiet for a +few moments and then, creeping to the edge, would peer over to see if +the male were still pursuing her. If he happened not to be hidden, she +would seem to see him, even when ten or twelve inches away, and would +quickly draw back.” + +Moreover that they have the ability to discriminate colours has been +shown by their behaviour when imprisoned in cages consisting of a +series of communicating chambers each with a glass top of a different +hue. They show a marked preference for the red chamber under these +circumstances while the least attractive colour seems to be blue. + +It has been known for a long time that the males of many kinds of +birds—and especially of the more ornamental species—are accustomed +to perform the most extraordinary antics in the presence of the female +at the time of mating. The Peckhams made the unexpected discovery that +precisely similar “love dances” took place in the case of the jumping +spiders. Even the comparatively sober-coloured “zebra spider” performs +a weird _pas seul_ in courting its mate, but its display is feeble +compared with that of some of the more ornate of the Attidae. + +Certain isolated observations on captive jumping spiders led these +observers to suspect that the mating habits were unusual and worthy of +accurate investigation, and they laid their plans accordingly, taking +their summer holiday a month earlier than usual, so as to miss nothing +of the pairing season, and including in their party an artist whose +drawings should furnish an indubitable record of the attitudes assumed +by the male spiders in their evolutions. + +On arriving at their destination they found a small species, _Saitis +pulex_, with no great claims to remarkable beauty, mature, and ready +to pair. A female was placed in one of the experimental boxes which +had been provided in advance, and a male was admitted on the following +day. He sighted her at a distance of twelve inches, and showing signs +of excitement, advanced to within about four inches and then performed +a most ludicrous dance—something in the nature of a “highland fling,” +in a semicircle before her, she, in the meantime, moving in such a +manner as to keep him always in view. His exact behaviour was this: +he extended all the legs—and the palp—on the left side, folding the +first two legs and the palp of the right side under him, and leaning +over sideways so far as nearly to lose his balance, and in this +attitude he sidled along towards the lowered (right) side till he had +described an arc of about two inches; then the position was instantly +reversed, the right legs being extended and the left folded under, and +the arc retraced. A male was seen to repeat this performance 111 times! +He then approached nearer and when almost within reach “whirled madly +around and around her, she joining and whirling with him,” after which +she accepted him as a mate. + +The next species to engage attention was an _Icius_. It was noteworthy +that although the neighbourhood was well known to the experimenters +they had never met with this spider before, but for a few days it +swarmed on the fences just as birds are known to assemble from all +quarters for the so-called “love dances.” After the mating season the +spiders wandered off into the woods again and were seen no more. + +[Illustration: Fig. 10. A male Attid spider (Astia vittata) dancing +before the female. (After Peckham.)] + +The performance was much as before, but the spiders assumed different +attitudes. The female lay flat on the ground with her front legs +raised; the male danced on the six hind legs, with the front legs +lowered and meeting at the tips. The males of this species were +exceedingly quarrelsome, sparring frantically whenever they met, but +their battles were entirely bloodless. “Indeed,” say the observers, +“having watched hundreds of seemingly terrible battles between the +males of this and other species, the conclusion has been forced upon us +that they are all sham affairs, gotten up for the purpose of displaying +before the females, who commonly stand by, interested spectators.” In +the case of one species, after two weeks of hard fighting between the +males, the Peckhams were unable to discover one wounded warrior. The +females, on the other hand, were often really formidable. _Phidippus +morsitans_ is an example. The male has handsome front legs, thickly +fringed with white hairs, and he displays these to the best advantage +in his love antics. Two males supplied in succession to one female “had +offered her only the merest civilities when she leaped upon them and +killed them.” + +In the case of most of the spiders whose love-dances were investigated, +the chief ornamentation of the male consisted of fringes of white or +coloured hairs on the face, the palps, and the front legs, and they +kept these parts always before the females, displaying their glories +to the utmost advantage. The male of _Habrocestum splendens_, however, +possesses an extremely brilliant abdomen, and, lest anything of its +beauty should be lost upon the object of his admiration, he varies the +ordinary performance in a remarkable manner. He often pauses in the +dance, and, raising his abdomen, “strikes an attitude” in which he +remains motionless for half a minute. Moreover he frequently turns his +back on the female—a most unusual occurrence in the course of these +antics. + +The males of one species, _Philaeus militaris_, were observed to +capture and keep guard over young females, which they imprisoned in +webs spun for the purpose until they had undergone their last moult and +were mature, chasing away all intruders in the interval. + +The jumping spiders furnish a much stronger case for those who believe +that ornamentation plays an important part in sexual selection +than do either birds or butterflies. With regard to the birds it +has been objected, first, that there is little evidence that the +females pay much attention to the antics of the males, and secondly, +that practically all the male birds pair, whatever their claims to +pre-eminent beauty. Now in the case of the jumping spiders the females +follow the performances of the males with the utmost attention, and +seeing that the males are present in large numbers when the females +begin to appear, the latter are certainly in the position to reject +such mates as do not please them. + +The mere relation of the results of this most interesting investigation +conveys no hint of the unwearied patience and close observation +necessary to those who would surprise the secrets of nature. One is +apt to infer that it is only needful to place some spiders in a box, +establish oneself in an arm chair, and ring on the performance, so +to speak. The Peckhams modestly remark: “The courtship of spiders is +a very tedious affair. We shall condense our descriptions as much as +possible, but it must be noted that we often worked four or five hours +a day for a week in getting a fair idea of the habits of a single +species.” + + + + +CHAPTER XI + +THERAPHOSID SPIDERS + + +It is quite impossible in a work like the present to deal with the +classification of spiders. About forty families have been established, +some of them of vast extent, the Attidae, for example, including some +four thousand species. The great French arachnologist, M. E. Simon, +has occupied 2,000 quarto pages in defining the families, sub-families +and genera, without concerning himself with the species at all! It is, +however, desirable, that the attention of the reader should be called +to the primary division of the group, according to which all spiders +are either _Araneae verae_ (true spiders) or _Araneae theraphosae_ +(theraphosid spiders.) + +Now these two kinds of spider may readily be distinguished by a single +easily observable characteristic, the nature of the mandibles or +_chelicerae_; but it is necessary to describe the spider’s mandibles +before the difference can be appreciated. + +Their nature is perhaps best explained by saying that each mandible +is not unlike a penknife with a single small blade, rather more than +half open when in use, closed when at rest. The handle of the penknife +is certainly in most cases very short and thick, and the blade not +really a blade at all, for it has no cutting edge, but is a “fang” or +piercing instrument generally somewhat curved, and with a sharp point. +The “blade” is, moreover, perforated by a tube which comes from the +poison-gland, situated in the thickened “handle,” or in the spider’s +head, so that poison can be forced into the wound which it inflicts. + +Now take two penknives with the blades half open and hold them so that +they hang with the hinge downward and with the blades directed towards +each other; it is clear that the blades may be made to pierce an object +situated between them by moving the handles laterally, the object being +attacked simultaneously on either side. This is the arrangement in the +true spiders, whose jaws move sideways, though they do not always hang +perpendicularly, but are more often somewhat slanted forwards. + +To represent the jaws of a theraphosid spider the penknives must be +arranged differently. Place the handles horizontally and parallel to +each other, with the blades directed downwards and also parallel. They +will now work not sideways, but up and down, and both fangs will pierce +the victim from above. In a word, the true spiders have jaws which can +be separated or brought together, and which tend to meet in the object +into which they are plunged, while the jaws of theraphosid spiders work +in parallel vertical planes, and strike downwards. + +All the spiders which have so far concerned us are _Araneae verae_, +and we have incidentally had occasion to note some of the principal +families of that division—Epeiridae (or Argiopidae as some prefer to +call them), Theridiidae, Agelenidae, Thomisidae, Lycosidae and Attidae. + +Indeed there is only one theraphosid spider that there is the least +likelihood of our coming across in this country. Their true home is +in hotter climes, and though stragglers from their army are not rare +in the warmer portions of temperate regions, they abound only in +tropical countries. They include the “Trap-door” spiders, common in +the Mediterranean region and in many other widely distant parts of the +world, and the great “Bird-eating” spiders of the tropics—the spiders +which are quite wrongly but universally alluded to in America as +Tarantulas. + +The single British example is well worth the study of any reader who is +fortunate enough to come across it. But he must first catch his hare, +for _Atypus affinis_ (or _piceus_ as it used to be called) does not +grow in every hedge-row, nor is it easy to find it where it does occur. +Most of the localities recorded are in the south of England. It is a +thick-set dark-coloured spider about half an inch in length, and with +very thick, powerful mandibles, which, as we have seen, work vertically. + +Its nest is a loosely-woven tubular structure, which partly lines a +more or less vertical hole in the ground and partly lies exposed on the +surface, but which does not present any obvious opening for entrance +and exit. + +The situation chosen is generally a sloping sandy bank covered with +vegetation. The burrow is about eight inches in depth and about three +quarters of an inch in diameter. Near the bottom it narrows and then +expands into a somewhat wider chamber where the spider lives and +constructs its egg-cocoon. The portion of the tube above the ground is +sometimes longer but more often shorter than the buried portion, and it +tapers to a closed end. + +Mr Joshua Brown, who first found this spider near Hastings in 1856, +took home several of the tubes with the spiders inside. He could find +no opening, and though the spiders moved up and down the tubes they +did not emerge. On tearing a tube open he found no remains of insects +inside, but in one case he came across a worm, partly within, and +partly outside the lower part of the tube, and apparently partially +devoured by the spider. + +The same species is not rare in France and M. Simon’s observations on +it closely agreed with those of Mr Brown. He believed that the spider +chiefly depended for its food on earthworms which, in the course of +their burrowings, came casually into its neighbourhood. Since these +observations, however, considerable light has been thrown on the habits +of the spider by Enock, who found colonies on Hampstead Heath and near +Woking. His investigations extended over several years, and wonderful +patience was needed before the secrets of this curious animal were +divulged. + +It appears that the female, when once established, never leaves the +nest at all! The aerial portion of the web was always a puzzle, but now +we know, thanks to Enock, that it constitutes the whole hunting ground +of the spider. Like promises and pie-crust it is apparently made to +be broken. If it is accidentally brushed against by a passing insect +the spider is instantly aware of the fact, rushes to the spot, and +transfixes the intruder with its powerful mandibles. It turns on its +back to do this, and strikes the insect from behind, afterwards pulling +its prey through the weft and into the tube by main force. It drags it +to the bottom of the tunnel, makes sure of its death, and immediately +returns and repairs the rent. + +Insects were held against the tube, and the spider, if hungry, accepted +them at once; if replete however, it always gave a tug at the tube, +which retracted a portion of it into the burrow—a curious action +which Enock quite learnt to interpret as the “I don’t want any more” +movement. + +The males made nests exactly like the females, but shallower, and they +left them to search for their mates, leaving the ends open. On finding +a female nest, they “serenaded” by tapping with their palps, and after +some delay, tore open the web and entered. By and by the female came +up and repaired the rent, first pulling the edges together with her +jaws and then uniting them with silk from her spinnerets. In one case +nothing more was seen of the male for nine months, when his empty skin +was observed at the end of the tube. After nine months of connubial +bliss his consort had devoured him! + +In the autumn and spring, eggs and newly-hatched young were often found +in the nests. Late in March a small hole, 1/16 inch in diameter, was +noticed at the end of some of the webs, and presently the young began +to emerge—never to return to the nest. They immediately climbed the +highest objects at hand, and some were seen to be carried off by the +breeze. + +Enock found, by an ingenious experiment, that the sand which is +incorporated in the aerial part of the tube—no doubt to render it +inconspicuous—is obtained from within, and not from outside the nest. +Carefully covering the exposed web, he powdered the ground all round +it with red brick-dust, but the particles which the spider embedded +in the web were of brown sand, evidently obtained from the bottom of +the burrow and not from the surrounding surface. But in the case of +some newly-dispersed young spiders he was able to see this operation +performed. The first part of the nest to be made was the aërial +portion, at the foot of which the digging was commenced. Particles of +sand were brought up in the jaws of the young spider and pushed into +the weft of the tube. Occasionally the jaws were thrust through the +delicate web and particles from without were seized and _pulled_ into +the silken fabric. + +It is sad to have to relate that such young spiders as did not emerge +from the web within a reasonable time were devoured by their unnatural +parent. It sometimes happened that a change of weather rendered it +unsuitable for the departure of the young, and in this case the mother +closed up the exit-hole, and retired to feed upon her offspring! Thus, +though there were as many as a hundred and forty in a brood, a good +many perished at the outset, and the ants in the surrounding soil +accounted for some of the rest. + +The Atypidae form a small outlying group of the Theraphosid spiders and +are able to live in colder regions than most of their relatives. The +great bulk of the division belong to the family Aviculariidae. + +Some of the Aviculariidae are not unlike Agelena in their mode of life, +spinning a dense sheet-web terminating in a tube, and entrapping +their prey. Far the greater number, however, as far as their habits +are known at all, are earth dwellers, either inhabiting more or less +complex burrows of their own, or sheltering under stones or in chance +cavities by day and emerging at night to seek food in the immediate +neighbourhood of their hiding-places. Some of them are quite small, but +the majority are large robust spiders, of formidable appearance. The +largest known spider, _Theraphosa leblondi_, is found in South America, +and its body measures more than three and a half inches in length. +Few spiders have attracted more attention than the fabricators of the +curious “trap-door” nests, which are common in the Riviera, and indeed +in all the countries bordering the Mediterranean. But abundant though +they are, they are extremely difficult to find, and it is generally +only by chance that their existence is detected. + +The Tarantula occasionally closes the mouth of her tunnel with a sheet +of silk in which are encrusted the _débris_ of insects or particles of +soil. She does this at the time when she is spinning her cocoon and +any intrusion is particularly inopportune, but she does it also on +other occasions which are not so easily accounted for. A reason which +would naturally occur to us would be the exclusion of excessive rain or +excessive sunshine, but the facts, unfortunately, do not accord with +this explanation. + +Now, however desirable occasional closure may be, a permanent door +would hamper the tarantula in her hunting operations, but the habits +of the trap-door spider are different, and she closes her retreat +with a wonderful hinged lid or “trap-door.” And the commonest form +of trap-door is also the most perfect, being thick and tapering, and +fitting accurately into the bevelled mouth of the tube like a stopper +in the mouth of a bottle. It is made of alternate layers of spider +silk and earth, and is free for more than half its circumference, the +remaining portion of the surface disc being attached to the side of the +tube by a flexible hinge of silk. Moggridge dissected the door of a +full-sized tunnel into fourteen graduated discs. The smallest—and of +course the lowest—represented the first door ever made by the spider, +and the successively larger discs indicated the stages at which its +increasing size rendered an enlargement of the tube—and therefore of +the door—necessary. + +The spider always interweaves vegetable matter from the +neighbourhood into each new disc, so that, as a rule, it is entirely +indistinguishable from its surroundings when closed; and not only +_dead_ vegetable matter, for if the tube is situated amongst moss, moss +grows upon the lid. From our previous experience, however, we shall +not be surprised to find that blind instinct and not forethought is +responsible for this action. Moggridge removed the lid of a tunnel +and also cleared the ground immediately round it of all vegetation; +nevertheless, when the spider made a new door, it covered it with moss +taken from the undisturbed vegetation beyond, so that the trap-door +was now conspicuous as a green oasis in a sandy desert! And on another +occasion a spider interwove fragments of scarlet fabric left purposely +at hand into the lid of its tunnel. It is clear, therefore, that the +decoration of the door is due to an instinct which impels the spider +to utilise any material of the neighbourhood without any regard to the +effect produced. + +The tube is densely lined with silk, which affords its architect a +secure foot-hold, and if any enemy attempts to open the lid from +without, the spider resists with all its strength—which is not +inconsiderable—clinging on to its under surface with its front legs +and jaws, while the claws of its other feet grasp the silken walls of +the tube. + +The other type of trap-door is less interesting and much more +elementary, consisting simply of a wafer-like sheet of silk mixed with +earth and vegetable matter, but it is a curious fact that while all +known trap-door nests of the cork type are simple tubes, the burrows +with wafer doors are often much more complex. In some cases there +is a branch tube, like that constructed by _Lycosa picta_, leaving +the main tunnel at a depth of some three inches, and reaching the +surface perhaps two inches away from the trap-door, so that the whole +excavation is +Y+-shaped. This branch tube is permanently closed +by a thin sheet of silk and earth, which, however, it would not be +difficult to break through if it were urgent for the spider to escape +while the enemy was exploring the main tunnel. + +But a more interesting case is the occurrence of another trap-door +some way down the tube. If the tube is unbranched, this forms merely a +second line of defence if the outer door is forced, but in the case of +a branched tube the additional door hangs at the fork of the +Y+, +and is so shaped as to form a perfect valve, so that the spider, by +holding it against one or the other side of the tunnel, can connect the +bottom limb of the +Y+ with either fork at will, leaving to the +intruder a beautifully smooth-lined tube to explore, with no hint of +the possibility of escape in other directions. + +There are sometimes other complications in the ramification of the +tube, but these need not detain us. Each species of spider adheres to +its own particular type of architecture, and may safely—in a given +neighbourhood—be identified by its nest. + +As with the Lycosidae, the burrowing is all done by the mandibles, +but here the first joint—the handle of the penknife—is of more +importance than the blade or fang. Indeed the burrowing species of the +Aviculariidae may be distinguished from the rest by their mandibles, +which are provided in front with a _rastellum_, or row of teeth for +digging. A trap-door spider, then, does not go to work like a rabbit, +or a terrier, scratching and kicking away the earth as it digs; it +laboriously dislodges particles of soil with its powerful mandibles, +and carries away the loosened fragments to deposit them at a distance. + +The trap-door spiders of the Mediterranean region are nocturnal +creatures, and little is known of their habits. Erber relates that a +species found in the island of Tinos comes out at night, fixes open the +trap-door with a few threads, and spins a web near its nest to entrap +passing insects, clearing away any trace of it before the dawn. In the +case of some Chinese and also some Australian species observers allege +that they frequently wander from their nests in the day-time. + +A Californian species was able to leave its nest when the trap-door was +weighted with three ounces of lead. On re-entering, it seized the edge +of the door with its mandibles, and, raising it slightly, inserted its +front legs. It then turned round and slipped backwards into the tube. +It always resisted the forcible opening of its door to the last moment, +when it let go and slid into the tube “as though going down a well.” + +The larger Aviculariidae have acquired a reputation for feeding on +birds, and this has given rise both to their scientific and their +popular name—bird-eating spiders. Several travellers have stated that +they have observed them with birds in their grasp, and there is no +doubt of their ability to kill any small bird or mammal, though it is +probable that they seldom have the opportunity, for they spin no snare +in which birds may be caught. Even without the aid of their poison, +their jaws are so large and powerful that they may easily attain the +vital organs of small animals. Probably their staple food consists of +the larger insects. + +They live in holes in the ground or in trees, or sometimes in the +fork of a tree-branch. In such hiding places they spend the hours of +day-light, emerging at night in search of food. Their large size and +uncanny appearance have attracted the attention of the collector, and +a great many species are known, but the fact that they chiefly inhabit +tropical countries has militated against any very extended study of +their habits, and the few items of information we possess are best +related with regard to the particular spider observed, and not taken as +necessarily characteristic of the whole tribe. There is little doubt +that they live for several years. McCook kept a specimen of _Dugesiella +hentzi_ in captivity for five and a half years, and he considered that +when it reached him it was at least a year and a half old, and probably +more. The same species has recently been made the subject of some very +interesting observations by Petrunkewitch, who obtained numerous living +specimens from Texas and kept them in captivity; unless carefully +packed, they bore the railway journey badly, and it was above all +things necessary to supply them with water. + +The captives were fed on grass-hoppers, crickets, cockroaches and +wolf-spiders, but they ate sparingly, one grass-hopper sufficing for +three days in the summer, while in the winter hardly any food at all +was taken. + +The sense of touch is extremely well developed in these spiders, but +in sight, hearing and smell they are strangely deficient. No response +whatever, was obtained to either high or low notes. A cricket sang for +hours quite close to a spider which had been kept hungry for several +days, without attracting any attention. It is very remarkable, by +the way, that insects show no instinctive dread of these formidable +creatures, not attempting to keep at a distance, and indeed frequently +running over them in trying to find a way out of the cage. Nor do the +spiders seem to be at all guided by smell; they evince no knowledge of +the presence of insects which emit a strong odour, nor do they react +to such tests as those to which the garden-spider was subjected unless +strong irritants such as chlorine are employed, in the perception of +which it is perhaps unnecessary that smell in the strict sense should +take any part. + +They have eight eyes—two of them round and rather business-like in +appearance, and the others oval or pear-shaped—and they are very +sensitive to light, retreating at once from the direct rays of the +sun or from a light flashed on them, but they do not appear to _see_ +anything at all, recognising neither friends nor enemies by sight, +however close at hand. It was far otherwise with a wolf-spider in the +same cage. Running towards the Dugesiella it was clearly aware of it at +a distance of several inches, and could not be persuaded to approach +nearer. But the supremacy of the sense of touch is most striking when +the spiders are courting. When the male is seeking the female he seems +quite unaware of her proximity unless he accidentally brushes up +against her. If he loses contact for a moment he is quite at sea and +wanders blindly about, turning, perhaps, to the left when the least +motion to the right would bring them together again. This frequently +happens when he has accidentally touched the female with one of the +hind legs. He immediately turns about, and if she is still there, all +is well, but if she has chanced to move out of reach, he is quite at a +loss. Neither sight nor sound nor smell guide him, but touch only. The +delicacy of this sense, however, is quite remarkable. He seems to be +aware at once of the nature of the object which touches him, assuming +a threatening attitude if the touch is hostile, or pouncing instantly +if hungry and the touch is that of a passing insect. If, however, the +insect is lucky enough to escape, it is in no danger of pursuit. + +As in the case of many spiders—though by no means of all—his courting +is not unattended with peril. The tragic fate which sometimes overtakes +the male spider has so hit the popular imagination that there is a +general impression that the female spider is a confirmed misanthrope +and desires the life of any suitor bold enough to approach her. Not at +all! We have simply to remember that spiders are carnivorous and prone +to cannibalism. If the female happens to be hungry she makes no nice +discrimination between an amorous male and a succulent grass-hopper; +if replete, she may find time for the play of softer emotions. The +male of _D. hentzi_ appears to be more or less prepared for a hostile +reception on the part of the female, for the thighs of his front legs +are furnished with spurs at their extremity and with these he holds +back and renders powerless her threatening fangs. + +There is no doubt that the spider’s delicate sense of touch resides in +the hairs with which both body and limbs are thickly clothed. They are +of various kinds—fine hairs, bristles, and stout spines—and many +of them are supplied with nerve-fibres at the base. The finer hairs +are probably not sensory, and they are, in the case of some Avicularid +spiders very easily shed, and have a strongly irritant action on the +hand that touches them, not unlike the sting of a nettle. + +It is not at all unusual for one large Avicularid spider, _Psalmopoeus +cambridgii_, to be brought over to England in cases of bananas from +the W. Indies. Mr James Adams of Dunfermline has kept two specimens +alive for a considerable time. The first specimen lived in captivity +for two years and nine months, during which it moulted five times but +grew very little in size. Arriving in September, it was at first fed +on flies, and in a few weeks, when these began to fail, it accepted +beetles, consuming about three a day. In November, even these insects +were difficult to obtain, and recourse was had to cockroaches. At first +about three cockroaches a week were eaten but the number decreased +until, in the middle of March it ceased feeding altogether, and on +April 13 it cast its skin. It moulted again in October, and twice a +year for the rest of its life—in spring and autumn. During six months +it took no food at all, and very little for four months previously. At +the last moult but one it lost a limb, which however, reappeared when +the spider again changed its skin, though it never attained the proper +size. + +With spiders, as with insects, moulting is a very serious matter, +involving much more than the mere casting off of an external coat. If +all does not go well limbs may easily be lost in the operation, nor is +it rare to meet with instances in which the animal has perished in its +unsuccessful attempt to discard the old integument. + +Mr Adams’ second specimen was kept alive for three years and ten +months. It moulted only once each year—in June or July—and it died in +the act of casting its skin. In the case of these spiders, also, it was +noted that insects supplied to them as food displayed no fear whatever. +There were always a few cockroaches in the same box, and they were +often observed actually with the spider in its nest, but no notice was +taken of them unless their host chanced to be hungry. A photograph of +this spider is given in the Frontispiece. + +It is an interesting fact that many of the Aviculariidae of Southern +Asia and Australia possess a sound-producing apparatus which is +entirely lacking in African and American forms, but this is a subject +which deserves a chapter to itself. + + + + +CHAPTER XII + +STRIDULATION + + +Many of the Arthropoda—the large group which includes insects and +crustaceans as well as Arachnida—are able to produce sounds, a fact +familiar enough in such insects as crickets and grass-hoppers. As, +however, the breathing apparatus of these animals is entirely different +from that of mammals and has no connection whatever with the mouth +and alimentary canal, the mode of sound production is not at all the +same. Instead of setting vocal chords in vibration by the expulsion of +air through the larynx, insects “sing” or “chirp” by rapidly rubbing +together certain specially roughened surfaces, which constitute what is +called a “stridulating organ.” In crickets, for instance, each tegmen +or wing-cover is provided with a kind of file, and when the wing-covers +are rapidly vibrated, the edge of each rubs against the opposite file, +and a loud shrill sound is produced. + +The stridulating apparatus is by no means always in the same place; the +thorax may rub against the abdomen, the leg against the wing-cover, +or one of the mouth appendages against another. Nor are the sounds +produced always audible to human ears; at all events there are many +creatures with what appear to be very well developed stridulating +organs whose note has never yet been heard by any naturalist, but there +are doubtless numberless sounds beyond the range of our hearing, which +is limited, like the keyboard of a piano. + +Now such a stridulating apparatus has been detected in many spiders, +and always in one of three situations—either between the two parts +of the body (cephalothorax and abdomen) or between the palps and the +mandibles, or between the palps and the front legs. In some of the +Theridiidae the hind end of the cephalothorax is roughened and fits +into a sort of socket in the abdomen which is provided with parallel +ridges, so that when the abdomen is vibrated the two surfaces are +rubbed together, but no one has yet heard a sound produced by these +spiders. The stridulating Aviculariidae, however, are easily heard, the +sound in some cases being described as a kind of whistle,—in others it +has been said to have the effect of shot dropping upon a plate. + +There are two quite distinct purposes for which sounds may be produced; +they may either serve as a call from one sex to the other, or as a +warning to intruders. Obviously the first purpose requires a sense +of hearing in the sex appealed to, and it is interesting to note +that in the Theridiidae, which are among the spiders which show some +appreciation of sound, the organ is well developed in the male only, +being rudimentary or altogether absent in the female, while in the +Aviculariidae, which appear to be quite deaf, both sexes possess it +equally. In them its function is probably to warn off its enemies—a +purpose for which it is not at all necessary that the spider itself +should hear it. + +Sometimes sounds have been quite wrongly attributed to spiders; there +is, for example, an Australian species widely known among natives +as the “barking” or “booming” spider, for no better reason than +that the spider has been found in the day-time at a spot where the +booming was heard at night. This case was investigated by Professor +Baldwin Spencer, who found that quails were really responsible for +the sounds with which the spider was credited. The creature could, +however, achieve a kind of whistle by rubbing its palps against its +mandibles. Its stridulating apparatus was of the type common among +the Aviculariidae. Its principle is that of the musical box, where +nail-like projections on a barrel strike against the teeth of a metal +comb, except that the barrel is stationary and the comb is moved up and +down against it. The barrel is here represented by the first joint of +the mandible which is beset on its outer side with spines. The inner +edge of the first joint of the palp is furnished with “keys” which +are rubbed against the mandible spines when the palps are vibrated. +These keys are very curious structures. They are of various lengths, +and their shape will perhaps be understood when it is said that a +tolerable model of one would be obtained by taking a flat iron bar, +sharpening it at the end, and then so twisting it in the middle that +the flat surface of one half is at right-angles to the flat surface of +the other half. Its appearance therefore varies according to the point +of view, the narrow edge of one half and the broad edge of the other +being visible at the same time. A moment’s consideration will show that +this torsion is calculated to give great rigidity to the keys, for when +the outer half is struck on the flat surface the inner half opposes +its greatest diameter to the shock. A similar structure is found in +all the Theraphosid spiders which are able to produce a sound, though +sometimes the “keys” are on the mandibles and the spines on the palp. + +[Illustration: Fig. 11. Three “keys” of a stridulating organ, after +Spencer.] + +In Staten Island there is a wolf-spider—_Lycosa kochi_—which is known +as the “purring” or “drumming” spider because of a curious habit which +the male has, at mating time, of rapidly drumming on the dead leaves in +a wood with its palps. It runs hither and thither over the ground as +if in search of something, pausing at short intervals to “purr,” and +the sound had frequently been heard and correctly attributed to the +spider before the way in which it is produced was discovered. In this +case it is probable that the production of sound is not the object of +the spider at all, for we have no evidence that wolf-spiders hear. On +the other hand rapid tapping with the palps is a very characteristic +action with male spiders at mating time, and it is easy to believe that +contiguous dry leaves would conduct vibrations to a female at some +distance away and inform her of the presence of the male. Just so, as +we have seen, our English Theraphosid announces his arrival by tapping +on the exposed part of the nest of the female. + + + + +CHAPTER XIII + +THE SPINNING APPARATUS, AND THE FEET + + +Seeing that the possession of spinnerets is a characteristic of all +spiders, and that a great deal of the interest attaching to their +life-history arises from their spinning operations, any account of +the group, however brief, would be incomplete without some attempt to +describe these remarkable organs. + +Among the spiders to which the attention of the reader has been +directed, some have been highly accomplished spinners, constructing +complicated snares, retreats and egg-cocoons, while in the case of +others the spinning work is very meagre and employed chiefly for the +protection of the eggs. As might be expected, the organs attain a very +much higher development in some spiders than in others, and the most +complex of all are those of the Epeiridae, the constructors of the +circular snare. + +Now in the first place it is rather striking that the spiders with the +most conspicuous spinnerets are by no means the most able spinners. The +“bird-eating” spiders are a case in point, for they spin very little, +yet two of their spinnerets are much more obvious than anything Epeira +has to show, for they protrude behind the body and strike the eye at +the first glance. Indeed excessive length has nothing to do with +complexity but is found wherever a wide sweep is necessary in laying +down the threads—as we saw in the case of Agelena, when constructing +its sheet-web. + +Roughly speaking, the spinnerets are very mobile finger-like +projections, generally situated under the hind end of the abdomen and, +bearing more or less numerous tubes from which the silken threads +proceed. The usual number of spinnerets is six, but there is a pretty +wide range, one group of spiders having only two, while a few possess +eight. + +The spinnerets, then, are only the bearers of the actual tubes which +emit the silk. The distribution of the tubes themselves is different +in the different kinds of spiders, but it is usually possible to +distinguish two kinds. There are generally present a large number of +very fine cylindrical tubes or “spools” and a few conical tubes of much +larger base, which are called spigots. Each of these orifices, whether +on spool or spigot, is connected by a fine tube with a separate silk +gland, or organ for manufacturing silk, situated within the spider’s +abdomen. Epeira has about 600 of such glands, each with its own +terminal spool or spigot, and the large number of these tubes has given +rise to a misconception that is very widely spread—namely that the +spider’s line, fine as it is, is “woven” of hundreds of threads of very +much finer silk. This is not so, as we shall presently see. + +Though Epeira has some 600 silk-glands, it has only five different +_kinds_ of gland, manufacturing silk of different properties. No other +family of spiders has so many, though two other kinds of gland have +been found in less elaborate spinners. Within the spider the silk is +fluid but it solidifies on meeting the air, each thread hardening as it +emerges though still continuous with the fluid contents of the gland, +so that the drawing out of a silken thread is just like the operation +so familiar with the glue-pot, or with spun glass, except that the +hardening is not due to cooling but to exposure to the air. This +general description will, it is hoped, make an account of the organs in +Epeira more comprehensible. + +The spinnerets of Epeira are so small and inconspicuous that their +disposition is not very easy to make out. When not in use they form +a tiny cone under the tip of the abdomen, and only four are visible, +their free ends being so brought together as entirely to conceal a +small central pair. There are really, then, three pairs of spinnerets +which we may call at once the anterior, median and posterior pairs, +though when at rest only the anteriors and posteriors can be seen. +If the spider is observed with a pocket-lens as it crawls about in a +glass tube it will be noticed that the spinnerets are capable of great +mobility. Their ends can be separated or brought together, or they may +be made to rub against each other or against the sides of the tube. +The anteriors and posteriors, moreover, are two-jointed though the +medians consist only of a single joint. + +So much can be seen without any great magnification, but the microscope +will be necessary if a complete understanding of their mechanism is to +be arrived at. What it reveals will now be briefly described, and will, +it is hoped, be made tolerably clear by the accompanying figures which +are simplified by the omission of a large number of bristles which tend +to hide the essential structure, and by a great reduction in the number +of “spools,” though the spigots are all indicated. + +The anterior spinneret (that nearest the head end of the animal) is a +sort of cone, divided into a large basal joint and a small terminal +joint. The latter bears on its inner side a single spigot (fig. 12 _a_) +and is crowned with a battery of spools, about a hundred in number. + +The median spinneret has three spigots, two at the tip and one on the +inner side (fig. 12 _b_), and about a hundred spools, mostly on its +inner surface. + +The posterior spinneret is divided very obliquely into two joints, so +that the terminal joint extends much lower down on the inner than on +the outer side. It has five spigots in groups of three and two, and +again there are about a hundred spools. + +Now the point that I wish to make clear is that there is no +interweaving of the output of these various spools and spigots. At the +moment of emission the threads are adhesive, and can be made to stick +to the glass or to one another, but they are not in any sense either +fused or interwoven. For ordinary operations the brunt of the work is +borne by the spigots marked _a_ in the figure, sometimes reinforced +by silk from the spigots on the median spinnerets marked _b_, the +functions of all the other spools and spigots being special and +occasional. For instance, when Epeira is laying down a foundation line, +this is what happens. The spider sits down, so to speak, on a twig, +separating its spinnerets and rubbing them on the surface. As it raises +its abdomen a multitude of little threads are seen merging into what +appears to be a single line. + +[Illustration: Fig. 12. View, from the inner side, of one of each of +the three spinnerets of _Epeira_. _A_, anterior; _B_, median; _C_, +posterior spinneret.] + +In reality the line is double, emerging from the spigots (_a_) on +the anterior spinnerets, and it can easily be separated into two—and +two only—any where along its length. The multitudinous spools have +emitted short lengths of silk to anchor the foundation line at its +commencement, but they are then closed and have no share in the +ever-lengthening line as the spider lets itself drop or crawls away +to attach it to a new spot. One of their uses, then, is to anchor +the main lines from the spigots to external objects, but they have +another function not less important. Everybody has seen a garden-spider +trussing up a captured fly. It is held in the jaws and front legs and +slowly revolved while with its hind legs the spider draws out bands of +silk from the spinnerets and swathes it like a mummy. No silken rope, +this, of fused or interwoven threads, but a broad band, every strand +of which is separate and distinct and proceeds from a different spool. +Two or three hundred fine threads wound simultaneously round the insect +form a much more effectual winding sheet than would a single cord +composed of them all. + +So far we have accounted for the spools, and for one pair of +spigots—those on the anterior spinnerets. The lower spigot (_b_) on +the middle spinneret often assists in laying down a foundation line +when extra strength is required. In that case the line is fourfold, and +can easily be split into four along its whole length, the threads from +the middle spinnerets being rather finer than those from the anterior, +but composed of the same kind of silk. + +There remain seven pairs of spigots whose function has still to be +explained, two on the middle and five on the posterior spinnerets. The +three which are clustered together on the posterior spinneret do not +form _silk_ at all, that is, the material they emit does not harden on +exposure to the air but remains fluid and adhesive. When the spider is +spinning the “viscid spiral” of its web it is from these spigots that +the sticky matter oozes, enveloping the true silken lines and presently +resolving itself into little globules in the manner already described. + +The remaining spigots—two on the middle and two on the posterior +spinnerets are employed only in spinning the egg-cocoon, and the silk +they produce is unlike that used in making the snare, being much +stronger and less elastic, and—in the case of the garden-spider—of +a yellow colour. In the occasional attempts which have been made to +substitute spiders for silkworms as commercial silk producers, it is +only this cocoon silk that has given any considerable results, the +produce of the other glands being far too frail for profitable use. +Such attempts, however, have always failed, principally for a reason +quite unconnected with the particular nature of the silk, namely, +the difficulty of keeping the spiders in captivity. It is a simple +matter to supply dozens of silkworms in the same box with mulberry +leaves, but spiders require separate compartments or they will fight +and devour each other, and the provision of suitable food for them is +such a troublesome matter that it has proved quite impracticable on a +commercial scale. + +We have incidentally seen that there are quite a number of different +operations in which the spinning apparatus takes part. There is the +line which most spiders lay down as they wander, and which secures +them from the danger of a fall if they lose their footing; there is +the snare for catching prey, the nest or retreat, and the egg-cocoon, +and in addition, silk from the spinnerets may be used to enwrap and +paralyse captured insects, or to assist the young spider to migrate. +Since the Epeiridae perform all these operations, and are, moreover, +the most finished of snare-makers, it does not surprise us to find in +them the highest development of the silk glands and the most complete +battery of spools and spigots on the spinnerets. Many spiders, as +we know, make no snare at all, and in the case of some, very little +spinning is attempted beyond the manufacture of a rather rudimentary +covering for the eggs. Naturally a less complex spinning apparatus is +required, and we accordingly find that jumping spiders, for instance, +have only about fifty silk-glands comprising three different kinds of +gland, while the glands found in such of the large Aviculariidae as +have been examined have been all alike. + +There is in some spiders a spinning organ, not to be found in +Epeira, which deserves a passing notice. It does not take the place +of spinnerets, of which the usual three pairs are present, but it +is situated in front of them, and only occurs in the female of the +species. Its peculiarity is that the silk does not emerge from +projecting spools; but through fine holes in a sieve-like plate, called +a _cribellum_, which is flush with the surface of the abdomen. It has +no mobility, therefore, and the threads from it have to be combed out +and distributed by the spider’s hind leg. For the better accomplishment +of this purpose there is a special comb of stiff hairs or bristles, +called a _calamistrum_, on each of the fourth pair of legs. + +The web of these spiders is not unlike that of Agelena, but of a rather +finer texture, and it can be seen, on magnification, to consist of +an irregular ground-work over which have been spread wavy bands of +excessively fine silk, combed out from the orifices of the cribellum +glands. Some of these cribellate-spiders, of the genus _Amaurobius_, +are not uncommon in our cellars and out-houses; their bodies are of +stouter build and their legs much shorter than those of the common +house-spider. + +We have no space for anything approaching a full description of the +anatomy of spiders, but there is one other point of structure of which +the reader has been promised some account. Attention was directed to +the fact that while some spiders are helpless on smooth perpendicular +surfaces unless they have lines to cling to, others can run with ease +upon the walls or even the ceiling, of a room. + +[Illustration: Fig. 13. Foot of Jumping Spider (on left), foot of +Garden Spider (on right).] + +The last joint or _tarsus_ of the spider’s leg is very different in +the two cases. It always terminates in claws—either two or three—so +that any species can make some show of climbing where the surface is +rough and there is anything to cling to, but to obtain a hold on a +polished surface it needs a special contrivance. This takes the form +of a pad of curiously modified hairs, called a _scopula_. The hairs +are club-shaped, narrow at their stalk and swelling towards the tip, +and their clinging power seems to be due to a viscid secretion. The +foot of any jumping spider will show this structure well. Epeira has no +scopula, and its climbing is always laborious unless it has a thread +to cling to, but it is supreme as a rope walker, treading daintily on +the most delicate threads, mounting a line “hand over hand” with great +agility, and manipulating the silk in its various spinning operations +with unerring skill and facility. + + + + +CHAPTER XIV + +THE ENEMIES OF SPIDERS + + +When one comes to consider the multitudinous risks to which a spider is +exposed during the whole course of its life it seems at first a little +surprising that the whole tribe has not long ago been exterminated. +Spiders continue to flourish, however, and it is very clear that +however careless Nature may be of the individual she is extremely +solicitous about the race. + +The infant mortality among these creatures must be appalling. There is +first their cannibalistic propensity to be reckoned with. Newly hatched +spiders while still within the cocoon seldom attack each other, but as +soon as ever each sets up for itself, no quarter is given. It often +happens that members of a brood of sedentary spiders spin their first +snares in close contiguity, and if food is scarce they eat one another +without compunction. It is said that a few individuals of a brood may +be reared to maturity on no other food than their sisters and brothers! +The case of the survivor of the “Nancy Bell” in the Bab Ballads would +be exceedingly commonplace in the aranead world. We have seen, too, +how, on occasion, _Atypus_ will devour her young if they do not leave +the nest with due expedition. Then if the weather conditions chance to +be unfavourable just at the period of departure from the cocoon broods +are liable to perish wholesale, washed away and destroyed by deluges of +rain; myriads, too, must be carried out to sea in the course of their +ballooning operations, and never come safely to land. + +But the mortality is probably even greater at a still earlier stage, +for hosts of spiders’ eggs never hatch at all, and this for two +reasons. In the first place, the silk of spiders is a favourite +material with many birds for the lining of their nests, and many of +them use the cocoons for this purpose. Secondly, there are numerous +Ichneumon flies which attack and parasitise spiders’ cocoons, piercing +them with their ovipositors and laying their eggs inside. The eggs of +the Ichneumon fly hatch first and feed upon the eggs of the spider. +Two such flies are known to attack the cocoons of the garden-spider, +and not a single spider will emerge from a cocoon thus parasitised. +The spiders whose cocoons are most subject to these attacks belong, +as might perhaps be expected, to the sedentary groups, and the most +elaborate but unavailing precautions are often taken to render them +Ichneumon-proof. The cocoons of the peripatetic wolf-spiders have never +been observed to be parasitised. + +Even if a spider has survived these early perils there are still many +dangers ahead. During its period of growth it has to moult some eight +or nine times, and the operation is at least as dangerous as, say, an +attack of measles to the human infant. For some time beforehand feeding +ceases, and the animal becomes inert and apparently dead, but presently +the integument splits, and out struggles the spider, pale and soft, and +leaving behind it not only the outer skin but the lining of most of +its alimentary canal and of its breathing tubes. Sometimes, as we have +said, it fails to extricate itself and dies; quite often it emerges +with the loss of a limb, which will reappear—reduced in size—at +the next moult. It is necessary to go into retreat for a time after +moulting, till strength has returned and the integument has hardened. + +But the dangers of moulting, though not negligible, are insignificant +beside others to which the spider is exposed during its later stages, +nor is a prolonged dearth of food necessarily fatal, for, as we have +seen, a spider can fast for an astonishing time and yet retain its +health if it has a fair supply of water. But there are terrible +enemies at hand from which it has little or no protection. Birds, +of course, come first, for to most insectivorous birds spiders are +acceptable morsels. I have seen a hedge sparrow going conscientiously +over a trellis work and picking out all the spiders from the nooks and +corners. Then insectivorous mammals make no distinction between the +Insecta and the Arachnida, and often eat spiders with avidity, as also +will toads and lizards. + +Moreover, Ichneumon flies do not confine their attention to cocoons, +but often attack well-grown spiders. They invariably lay their eggs on +one spot—at the very front of the abdomen, near the cephalothorax, +where the spider is powerless to dislodge them. The egg hatches out +to a grub which is a veritable “old man of the sea” on the spider’s +back, and there it remains until it causes the death of its victim by +feeding on the contents of the abdomen. Four such Ichneumon flies have +been found to attack the garden-spider, and no kind of spider seems +exempt. How they contrive to deposit their eggs in the proper place +without great danger of themselves falling a prey to their victims +is a mystery. To venture into a garden-spider’s web for the purpose +would seem a fool-hardy proceeding. The actual deposition of the egg +has seldom been witnessed, but in one of the few cases that have come +under observation the spider made little resistance and appeared quite +demoralised. It was hanging from a thread, down which the Ichneumon fly +was seen to crawl. When it reached the spider the latter dropped an +inch lower on two or three occasions but then remained passive, and the +parasite on nearing it, turned round, backed down the line, and with +great care and deliberation attached an egg at the usual spot. + +But no enemies of spiders are more terrible than some of the solitary +wasps, and gruesome indeed is the fate of any creature that falls +into their clutches. The social wasps often capture spiders to feed +their young but in their case the proceeding is summary and without +any finesse. They merely catch a spider, sting it to death, cut it +to pieces with their jaws, and feed it into the mouths of their +expectant grubs. The treatment is brutal enough, but at all events it +is expeditious. Now the solitary “digger” wasps never see their young. +They make cells, either by burrowing in the ground or by agglomerating +particles of mud or gravel, and in each cell is placed an egg together +with sufficient food to last the grub which hatches out for the whole +of its larval existence. The mother will not be at hand—as is the +social worker-wasp—to supply new food as required, and it is therefore +necessary so to arrange matters that the food provided may retain its +fresh condition for at least a fortnight. On the other hand the victims +must be deprived of all power of motion, otherwise the egg will stand +a great chance of being displaced and crushed, and even if it hatches +it will be unable to commence its meal upon the struggling spider. + +Now in the whole range of animal instinct there is nothing more +remarkable than the manner in which the solitary wasps have learnt to +solve this problem. The solution lies in so stinging the victim that +it is paralysed but not killed, and though quite unable to move, it +neither shrivels nor decays, but remains perfectly sound and edible for +two or three weeks. To accomplish this result the wasp acts as though +it possessed a knowledge of the minute anatomy of its victim, and +knew to a hair’s breadth the position of the principal nerve ganglia +which control its actions. Into these it unerringly thrusts its sting. +But even accuracy of aim is not everything; there must be the finest +discrimination in the severity of the wound. A slight excess, and the +animal is killed; too timid a thrust will not destroy movement. When +the delicate operation has been successfully performed, the paralysed +spider is dragged into the cell, placed on its back, and an egg +carefully deposited at the base of its abdomen, after which the cell +is sealed up. Some wasps, instead of providing a single large spider, +store their cells with a number of smaller victims, all rendered limp +and motionless. + +In attacking a spider the first action of one of these wasps is to +remove it from its natural environment. A garden-spider in its web, or +a burrowing spider in its tunnel are more or less formidable, but if +the one can be thrown down, or the other dragged forth into the open, +they are well-nigh defenceless. Therefore in attacking an Epeirid the +wasp first darts at it, seizes a leg, and attempts to jerk it out of +the web. If unsuccessful, the spider will now be on its guard, and the +wasp leaves it and tries the same manœuvre on another individual. Taken +by surprise, it is instantly thrown to the ground, and can then offer +no effectual resistance. Even the large “bird-eaters” fall victims to +these terrible foes. + + + + +CHAPTER XV + +SOME CONCLUDING REFLEXIONS + + +In the foregoing pages we have been able to deal with very few out of +the vast number of known spiders; yet the examples we have chosen for +study are fairly typical of some of the more important groups, and +calculated to give a tolerably just idea of the general economy of the +tribe. In any case even such a fragmentary study as the present gives +us food for thought. There is a question which the writer has so often +been asked that he is inclined to deal with it in anticipation, though +perhaps he is wronging his readers in supposing that they desire to +propound any such conundrum. This question is: What is the _use_ of +spiders? + +Now underlying this question there is surely a very unwarranted +assumption that all the myriad creatures which exist have, as a reason +for their existence, some reference to the activities and desires of +mankind. As far as it has any meaning at all it amounts to this: What +benefit does man derive from spiders? But it seems to take for granted +that some benefits must accrue to man from these creatures, or they +would not have the audacity to persist in living. Well, if the question +in this amended form is in urgent need of an answer, the reply must +be: very little if any. Certainly spiders prey as a rule on insects +and no doubt kill many which might injure us, and in the constant +battles between man and insect pests, instances have been recorded +where particular species of spider have fought on the side of man with +appreciable effect. But then they are as likely to devour our insect +friends as our insect enemies, impartially slaying the just together +with the unjust, so that little stress can be laid on their utility on +this score. Indeed there is quite as good a case to be made out of man +benefiting spiders as of spiders benefiting man, for his architectural +proclivities have provided some species with secure homes from which +most of their enemies—except man himself—are excluded, and where they +are sheltered from the storms which are so fatal to their relatives +outside, protected from extremes of temperature, and rendered so +independent of times and seasons that the number of broods they produce +in the year has increased. Whether a creature is useful or injurious +is entirely a matter of the point of view. There are several animals +with regard to which the opinions of the farmer and the gamekeeper are +diametrically opposed! + +But if anything emerges from the study in which we have been engaged, +it is surely this fact: that wherever there is a niche in nature +capable of sustaining life, to that niche some animal will sooner or +later adapt itself without any reference to man’s desires or interests. +We have seen spiders, all built on the same ground-plan, so to speak, +and with the same essential organs, so modified in the details of +structure and inherited instincts as to be able to thrive under the +most diverse conditions. Think, for instance, of the water-spider +and the desert Tarantula, or consider the difference in mode of life +between the sedentary garden-spider and the hunting Attid. + +Incessant competition in the struggle for life no doubt urged on +primeval spiders to strike out new modes of existence. Under slightly +novel conditions the best adapted or most adaptable survived and +were pioneers in the occupation of a new territory till the widely +different capacities and habits which we now wonder at were slowly +evolved. + +Another point to ponder on is the wonderful complexity of the instincts +which govern the actions of spiders; the extraordinary operations +they can perform, entirely untaught, and of the object of which it is +impossible to believe they are aware. We have seen that, in the most +highly organised species, the sense organs—except perhaps that of +touch—are but moderately developed, and the power of memory, the basis +of intelligent action, but feeble; yet their inherited impulses suffice +for all ordinary emergencies, and recur with unfailing precision at +the proper periods of their lives. They are machine-like, perhaps, but +what extraordinarily competent machines! The light of what we call +intelligence burns low, but a glimmer of it can be detected here and +there. + +If one comes to think of it, the egg of a creature of complex instincts +is a particularly wonderful atom; it contains not only the germs of all +the complicated bodily structure, but there are bound up in it also +the impulses that are to come into play at certain definite periods +only of the spider’s life-history. And these impulses are not mere +vague reminders that now is the time to spin a snare, or to weave an +egg-cocoon; they prescribe precisely how it is to be done, involving +perhaps a dozen different spinning operations in one unvarying order. +Viewed in this light, the germ of an insect or a spider would seem +in a sense to be more complex than that of an animal whose vague +instinctive impulses are under the direction of intelligence, and can +be carried out in a variety of ways according to circumstances. + +One of the most surprising things about the egg of a spider is the +amount of _energy_ stored up in it. A bird’s egg, huge in comparison, +contains material sufficient to build up the body of a fledgeling just +sufficiently active to be able to accept from the mother that first +nutriment without which it will speedily die. + +But turn back to the account of the tarantula-spider. Its egg is +small—perhaps the twelfth of an inch in diameter; yet it not only +produces a spiderling complete in form, and provided with all the +complex instincts of its tribe, but there is so much energy to spare +that, for months, without any new food-supply, the young spider +can lead an active life, frequently descending from and remounting +its mother’s back, and can even put forth silk on its own account! +The objects which a conjuror produces from a hat seem trifles in +comparison with the outcome of a spider’s egg—the actual material +seems astonishing from so small a source, but whence comes all this +surprising surplus of energy? Fabre suggests that it is supplied by +the direct rays of the sun, to which the Tarantula exposes in turn all +parts of the egg-cocoon. + +All through their lives spiders seem to be gifted in a high degree with +the power of extracting the utmost value, in substance and in energy, +from their food. Consider the great Theraphosid spiders—the so called +bird-eaters. They have a massive body, and great muscular power to +sustain; yet they are never heavy feeders and can go for many months +without any food at all. And it is not as though they were dormant +during this period of abstention; their vital processes seem to be +going on as usual the whole time, and they are ready at any moment +to resent attack, or to employ their spinning organs during their +long fast. True hibernation, as we have seen, does not occur in this +group; if it did, there would be nothing remarkable in the occasional +long abstention from food. The vitality of a hibernating animal is +practically at a standstill; all its vital operations—breathing, +blood-circulation, muscular action—are reduced to the lowest possible +limit, and it very likely expends no more energy during its winter +sleep than it would during a day or two of active summer life. + +But of such reflexions there is no end, and many such will doubtless +arise spontaneously in the mind of the thoughtful reader, and it is for +that very reason that the study of the life-history of any animal is of +such absorbing interest. It is not contended that spiders are any more +wonderful than any other group that might have been selected. There +is, of course, a special interest attaching to the study of animals +very much nearer to man in bodily structure and mental equipment, but +the endeavour to understand the actions and appreciate the outlook on +nature of creatures far remote from man, however unsuccessful, has its +own fascination. + +And this is what the mere collector entirely misses. Collecting is +of course necessary, for a complete examination is never possible in +the living specimen, and moreover without examples kept as types for +reference we should lose our way in the multitude of living forms. But +as an end in itself it is of vastly inferior value. The writer will be +well content if he has succeeded in arousing the curiosity of some with +regard to the humble life that surrounds us, and in stimulating a few +who possess the requisite keenness and patience to add to our store of +knowledge by new observations of their own. + + + + +LITERATURE + + +Most of the large publications on the Arachnid fauna of different +countries give some preliminary account of the habits of spiders, but +the only considerable work entirely devoted to that subject is McCook’s +_American Spiders and their Spinning-work_ (Philadelphia, 1893). A +small but interesting book on _The Structure and Habits of Spiders_ +was published ten years previously by Emerton (Boston, 1883). But the +reader who wishes to pursue further the study of some point to which +his attention has been called in the foregoing pages may desire to be +referred, for fuller details, to the original papers. + +Many writers have described the spinning of the circular snare, +and indeed it is quite easy for any one to watch the operation for +himself; but McCook goes into the matter in great detail and figures +many interesting variants of its normal form. J. H. Fabre’s delightful +_Souvenirs entomologiques_ (Delagrave, Paris) have been issued at +intervals for many years past, and mostly deal with insects. In +Series 9, however, he has an entertaining chapter on “Les Epeires.” +That the “viscid globules” arranged themselves mechanically was first +demonstrated by C. V. Boys (_Nature_, xl, 1889, p. 250). The same +writer experimented on the sense of hearing in spiders (_Nature_, +xxiii, 1880, p. 149). The interesting paper by G. and E. Peckham on the +mental powers of spiders is to be found in the _Journal of Morphology_ +(Boston U.S.A. i, 1887, p. 403.) + +The aeronautic habit has engaged the attention of many arachnologists. +Blackwall dealt with it in various papers in the _Transactions of the +Linnaean Society_ between 1833 and 1841, but the most complete account +is to be found in McCook’s original papers which are summarised in his +book already cited. + +With regard to the spinning operations of _Agelena_ the reader may +consult a paper by the present writer in the _Annals and Magazine of +Natural History_, August, 1891. + +The habits of the Water Spider were first described by de Lignac in +a _Mémoire_ published in 1749. Since that date many writers, notably +Wagner and Plateau, have dealt with the subject. The paper by the +last named in the _Annales des Sciences naturelles_, 1867, p. 345, is +particularly worth reading. + +E. Peckham deals with “Protective Resemblances in Spiders” in the +publication of the _Natural History Society of Wisconsin_ for 1889. + +The reader interested in the habits of the Wolf-spiders must certainly +consult the chapters on “La Lycose de Narbonne” in Series 9 of Fabre’s +_Souvenirs entomologiques_. + +The classical account by the Peckhams, of the love dances of jumping +spiders appeared conjointly with the paper by E. Peckham on “Protective +Resemblances” cited above. + +For the habits of _Atypus affinis_ (or _piceus_) the reader is referred +to the very complete account given by Enock in the _Transactions of the +Entomological Society_ (London, 1885, p. 394) of observations extending +through several years. + +The larger Aviculariidae have been dealt with in various papers by +Pocock, and the particulars given with regard to _Dugesiella_ were +taken from a paper by Petrunkevitch in the _Zoologischen Jahrbüchern_, +xxxi, 1911. + +In the _Archiv für Naturgeschichte_, i, 1889, Apstein published an +admirable piece of research on the structure and function of the +spinning glands of spiders. He investigated the glands present in the +various families, and the particular arrangement of the spools and +spigots on the spinnerets. + +A paper by the present writer in the _Quarterly Journal of +Microscopical Science_ for April 1890 continued this investigation, and +shewed the special operations in which the various glands participated +in the case of the Garden Spider. + + + + +INDEX + + +Aerial flights, 32 + +_Agelena_, 38-46 + +Agelenidae, 11, 38 + +_Araneae theraphosae_, 87 + +_Araneae verae_, 87, 89 + +_Argyroneta_, 3, 49, 50, 51, 52 + +Arthropoda, 6 + +Attidae, 4, 33, 52, 76-87 + +Atypidae, 93 + +_Atypus affinis_, 89, 121 + + +Balloons, 34 + +Banana spider, 103 + +Barking spider, 107 + +Bird-eating spiders, 25, 89, 99 + +Body parasites, 123 + +Burrows, 63 + + +Calamistrum, 118 + +Cannibalism, 33, 120 + +Carrying the young, 73 + +Characteristics of spiders, 4 + +Chelicerae, 10, 87 + +Cocoon, 12, 44, 64 + +Cocoon of _Agelena_, 44 + +Crab-spiders, 52 + +Cribellum, 118 + +Crustacea, 6 + +_Cyclosa conica_, 28 + + +Darwin’s Pike, 22 + +_Desis_, 49 + +Drassidae, 11 + +Drumming spider, 109 + +_Dugesiella hentzi_, 99 + + +Educability, 22, 27, 28 + +Egg parasites, 121 + +Enemies of spiders, 120 + +Energy stored in the egg, 130 + +_Epeira_, 3, 19, 112-116, 119 + +_E. diademata_, 13 + +Eyes of jumping spiders, 78 + + +Feet of spiders, 119 + +Foundation lines, 13, 14, 16, 17 + + +Garden-spider, 2, 13, 15, 19, 20, 23, 27, 39, 78, 121, 123, 126, 128 + +Gossamer, 36 + + +Habits of _Agelena_, 38 + _Atypus_, 90 + Jumping spiders, 79 + Tarantula, 69 + Theraphosid spiders, 99 + Trap-door spiders, 95 + +Harvest spiders, 8 + +Hearing, 23, 101 + +_Heteropoda venatorius_, 37 + +Hibernation, 2, 131 + +Hub, 13, 14 + +Huntsman spider, 37 + +_Hyptiotes paradoxus_, 31 + + +Infant mortality, 120, 121 + +Instinct, 21, 22, 29, 46, 129 + + +Jumping spiders, 4, 76-87 + + +_Linyphia_, 3, 32 + +Love dances, 82-87 + +Lung-books, 10 + +_Lycosa kochi_, 109 + +_Lycosa picta_, 61 + +Lycosidae, 5, 33, 52, 58-76 + + +Mammillae, 10 + +Marine spiders, 49 + +Mental powers, 20 + +_Meta segmentata_, 23 + +Mimicry, 55-58 + +_Misumena_, 54 + +Moulting, 104, 122 + + +Notched zone, 13, 14 + + +_Philodromus_, 54 + +_Phrynarachne_, 57 + +_Pirata_, 59, 66 + +Poison of spiders, 75 + +Poison gland, 88 + +_Psalmopoeus cambridgii_, frontispiece, 103 + +Purring spider, 109 + + +Rastellum, 98 + +Recognition of cocoons, 66 + +Red spider, 8 + +Scopula, 119 + +Sight, 23, 60, 81, 101 + +Silk glands, 111, 112 + +Smell, 25, 100 + +Solitary wasps, 124, 125 + +Spigots, 111, 113-116 + +Spinnerets, 8, 110-118 + +Spinning apparatus, 110 + +Spinning glands, 111 + +Spinning operations, 117 + +Spools, 111, 113, 114, 115 + +Starvation, 122 + +Stridulation, 25, 105 + +Stridulating Keys, 107, 108 + + +Tarantula, 68-74, 128 + +Tarsus, 119 + +Taste, 26 + +_Theraphosa leblondi_, 94 + +Theraphosidae, 25, 87-104 + +Theridiidae, 33 + +_Theridion_, 3, 23, 32 + +Thomisidae, 33, 52 + +Touch, 27, 101, 102 + +Tracheae, 6 + +Trap-door spiders, 89, 94, 98 + +Trap-snares, 31 + + +Use of spiders, 127 + + +Viscid spiral, 15, 18, 19, 20, 116 + + +Water-spiders, 48-52 + +Wolf-spiders, 58, 76 + + +Zebra spider, 77 + + +CAMBRIDGE: PRINTED BY JOHN CLAY, M.A. AT THE UNIVERSITY PRESS + + + + +THE + +CAMBRIDGE MANUALS + +OF SCIENCE AND LITERATURE + + Published by the Cambridge University Press under the general + editorship of P. Giles, Litt.D., Master of Emmanuel College, and + A. C. Seward, F.R.S., Professor of Botany in the University of + Cambridge. + + A series of handy volumes dealing with a wide range of subjects + and bringing the results of modern research and intellectual + activity within the reach both of the student and of the + ordinary reader. + + +HISTORY AND ARCHAEOLOGY + + 42 Ancient Assyria. By Rev. C. H. W. Johns, Litt.D. + + 51 Ancient Babylonia. By Rev. C. H. W. Johns, Litt.D. + + 40 A History of Civilization in Palestine. By Prof. R. A. S. + Macalister, M.A., F.S.A. + + 78 The Peoples of India. By J. D. Anderson, M.A. + + 49 China and the Manchus. By Prof. H. A. Giles, LL.D. + + 79 The Evolution of New Japan. By Prof J. H. Longford. + + 43 The Civilization of Ancient Mexico. By Lewis Spence. + + 60 The Vikings. By Prof. Allen Mawer, M.A. + + 24 New Zealand. By the Hon. Sir Robert Stout, K.C.M.G., LL.D., + and J. Logan Stout, LL.B. (N.Z.). + + 85 Military History. By the Hon. J. W. Fortescue. + + 84 The Royal Navy. By John Leyland. + + 76 Naval Warfare. By J. R. Thursfield, M.A. + + 15 The Ground Plan of the English Parish Church. By A. Hamilton + Thompson, M.A., F.S.A. + + 16 The Historical Growth of the English Parish Church. By A. + Hamilton Thompson, M.A., F.S.A. + + 68 English Monasteries. By A. H. Thompson, M.A., F.S.A. + + 50 Brasses. By J. S. M. Ward, B.A., F.R.Hist.S. + + 59 Ancient Stained and Painted Glass. By F. S. Eden. + + 80 A Grammar of English Heraldry. By W. H. St J. Hope, Litt.D. + + +ECONOMICS + + 70 Copartnership in Industry. By C. R. Fay, M.A. + + 6 Cash and Credit. By D. A. Barker. + + 67 The Theory of Money. By D. A. Barker. + + 86 Economics and Syndicalism. By Prof. A. W. Kirkaldy. + + +LITERARY HISTORY + + 8 The Early Religious Poetry of the Hebrews. By the Rev. E. G. + King, D.D. + + 21 The Early Religious Poetry of Persia. By the Rev. Prof. J. + Hope Moulton, D.D., D.Theol. (Berlin). + + 9 The History of the English Bible. By John Brown, D.D. + + 12 English Dialects from the Eighth Century to the Present Day. + By W. W. Skeat, Litt.D., D.C.L., F.B.A. + + 22 King Arthur in History and Legend. By Prof. W. Lewis Jones, + M.A. + + 54 The Icelandic Sagas. By W. A. Craigie, LL.D. + + 23 Greek Tragedy. By J. T. Sheppard, M.A. + + 33 The Ballad in Literature. By T. F. Henderson. + + 37 Goethe and the Twentieth Century. By Prof. J. G. Robertson, + M.A., Ph.D. + + 39 The Troubadours. By the Rev. H. J. Chaytor, M.A. + + 66 Mysticism in English Literature. By Miss C. F. E. Spurgeon. + + +PHILOSOPHY AND RELIGION + + 4 The Idea of God in Early Religions. By Dr F. B. Jevons. + + 57 Comparative Religion. By Dr F. B. Jevons. + + 69 Plato: Moral and Political Ideals. By Mrs J. Adam. + + 26 The Moral Life and Moral Worth. By Prof. Sorley, Litt.D. + + 3 The English Puritans. By John Brown, D.D. + + 11 An Historical Account of the Rise and Development of + Presbyterianism in Scotland. By the Rt Hon. the Lord Balfour of + Burleigh, K.T., G.C.M.G. + + 41 Methodism. By Rev. H. B. Workman, D.Lit. + + +EDUCATION + + 38 Life in the Medieval University. By R. S. Rait, M.A. + + +LAW + + 13 The Administration of Justice in Criminal Matters (in England + and Wales). By G. Glover Alexander, M.A., LL.M. + + +BIOLOGY + + 1 The Coming of Evolution. By Prof. J. W. Judd, C.B., F.R.S. + + 2 Heredity in the Light of Recent Research. By L. Doncaster, + Sc.D. + + 25 Primitive Animals. By Geoffrey Smith, M.A. + + 73 The Life-story of Insects. By Prof. G. H. Carpenter. + + 48 The Individual in the Animal Kingdom. By J. S. Huxley, B.A. + + 27 Life in the Sea. By James Johnstone, B.Sc. + + 75 Pearls. By Prof. W. J. Dakin. + + 28 The Migration of Birds. By T. A. Coward. + + 36 Spiders. By C. Warburton, M.A. + + 61 Bees and Wasps. By O. H. Latter, M.A. + + 46 House Flies. By C. G. Hewitt, D.Sc. + + 32 Earthworms and their Allies. By F. E. Beddard, F.R.S. + + 74 The Flea. By H. Russell. + + 64 The Wanderings of Animals. By H. F. Gadow, F.R.S. + + +ANTHROPOLOGY + + 20 The Wanderings of Peoples. By Dr A. C. Haddon, F.R.S. + + 29 Prehistoric Man. By Dr W. L. H. Duckworth. + + +GEOLOGY + + 35 Rocks and their Origins. By Prof. Grenville A. J. Cole. + + 44 The Work of Rain and Rivers. By T. G. Bonney, Sc.D. + + 7 The Natural History of Coal. By Dr E. A. Newell Arber. + + 30 The Natural History of Clay. By Alfred B. Searle. + + 34 The Origin of Earthquakes. By C. Davison, Sc.D., F.G.S. + + 62 Submerged Forests. By Clement Reid, F.R.S. + + 72 The Fertility of the Soil. By E. J. Russell, D.Sc. + + +BOTANY + + 5 Plant-Animals: a Study in Symbiosis. By Prof. F. W. Keeble. + + 10 Plant-Life on Land. By Prof. F. O. Bower, Sc.D., F.R.S. + + 19 Links with the Past in the Plant-World. By Prof. A. C. + Seward, F.R.S. + +PHYSICS + + 52 The Earth. By Prof. J. H. Poynting, F.R.S. + + 53 The Atmosphere. By A. J. Berry, M.A. + + 81 The Sun. By Prof. R. A. Sampson, D.Sc., F.R.S. + + 65 Beyond the Atom. By John Cox, M.A. + + 55 The Physical Basis of Music. By A. Wood, M.A. + + 71 Natural Sources of Energy. By Prof. A. H. Gibson, D.Sc. + + +PSYCHOLOGY + + 14 An Introduction to Experimental Psychology. By Dr C. S. Myers. + + 45 The Psychology of Insanity. By Bernard Hart, M.D. + + 77 The Beautiful. By Vernon Lee. + + +INDUSTRIAL AND MECHANICAL SCIENCE + + 31 The Modern Locomotive. By C. Edgar Allen, A.M.I.Mech.E. + + 56 The Modern Warship. By E. L. Attwood. + + 17 Aerial Locomotion. By E. H. Harper, M.A., and Allan E. + Ferguson, B.Sc. + + 18 Electricity in Locomotion. By A. G. Whyte, B.Sc. + + 63 Wireless Telegraphy. By Prof. C. L. Fortescue, M.A. + + 58 The Story of a Loaf of Bread. By Prof. T. B. Wood, M.A. + + 47 Brewing. By A. Chaston Chapman, F.I.C. + + 82 Coal-Mining. By T. C. Cantrill. + + 83 Leather. By Prof. H. R. Procter. + + * * * * * + +“A very valuable series of books which combine in a very happy way a +popular presentation of scientific truth along with the accuracy of +treatment which in such subjects is essential.... In their general +appearance, and in the quality of their binding, print, and paper, +these volumes are perhaps the most satisfactory of all those which +offer to the inquiring layman the hardly earned products of technical +and specialist research.”—_Spectator_ + +“A complete set of these manuals is as essential to the equipment of +a good school as is an encyclopaedia.... We can conceive no better +series of handy books for ready reference than those represented by the +Cambridge Manuals.”—_School World_ + +Cambridge University Press +C. F. Clay, Manager +LONDON: Fetter Lane, E.C. +EDINBURGH: 100 Princes Street + + + + + + + +End of the Project Gutenberg EBook of Spiders, by Cecil Warburton + +*** END OF THE PROJECT GUTENBERG EBOOK 44496 *** |