Chapter XV. The Labyrinth Spider
Jean-Henri Fabre The Life of the Spider
Water Spider With an Air Bell
While the Epeirae, with their gorgeous net-tapestries, are incomparable weavers, many other Spiders excel in ingenious devices for filling their stomachs and leaving a lineage behind them: the two primary laws of living things. Some of them are celebrities of long-standing renown, who are mentioned in all the books.
Certain Mygales (1) inhabit a burrow, like the Narbonne Lycosa, but of a perfection unknown to the brutal Spider of the waste-lands. The Lycosa surrounds the mouth of her shaft with a simple parapet, a mere collection of tiny pebbles, sticks and silk; the others fix a movable door to theirs, a round shutter with a hinge, a groove and a set of bolts. When the Mygale comes home, the lid drops into the groove and fits so exactly that there is no possibility of distinguishing the join. If the aggressor persist and seek to raise the trap-door, the recluse pushes the bolt, that is to say, plants her claws into certain holes on the opposite side to the hinge, props herself against the wall and holds the door firmly.
Another, the Argyroneta, or Water Spider, builds herself an elegant silken diving-bell, in which she stores air. Thus supplied with the wherewithal to breathe, she awaits the coming of the game and keeps herself cool meanwhile. At times of scorching heat, hers must be a regular sybaritic abode, such as eccentric man has sometimes ventured to build under water, with mighty blocks of stone and marble. The submarine palaces of Tiberius are no more than an odious memory; the Water Spider's dainty cupola still flourishes.
If I possessed documents derived from personal observation, I should like to speak of these ingenious workers; I would gladly add a few unpublished facts to their life-history. But I must abandon the idea. The Water Spider is not found in my district. The Mygale, the expert in hinged doors, is found there, but very seldom. I saw one once, on the edge of a path skirting a copse. Opportunity, as we know, is fleeting. The observer, more than any other, is obliged to take it by the forelock. Preoccupied as I was with other researches, I but gave a glance at the magnificent subject which good fortune offered. The opportunity fled and has never returned.
Let us make up for it with trivial things of frequent encounter, a condition favourable to consecutive study. What is common is not necessarily unimportant. Give it our sustained attention and we shall discover in it merits which our former ignorance prevented us from seeing. When patiently entreated, the least of creatures adds its note to the harmonies of life.
In the fields around, traversed, in these days, with a tired step, but still vigilantly explored, I find nothing so often as the Labyrinth Spider (Agelena labyrinthica, CLERCK.). Not a hedge but shelters a few at its foot, amidst grass, in quiet, sunny nooks. In the open country and especially in hilly places laid bare by the wood-man's axe, the favourite sites are tufts of bracken, rock-rose, lavender, everlasting and rosemary cropped close by the teeth of the flocks. This is where I resort, as the isolation and kindliness of the supports lend themselves to proceedings which might not be tolerated by the unfriendly hedge.
Several times a week, in July, I go to study my Spiders on the spot, at an early hour, before the sun beats fiercely on one's neck. The children accompany me, each provided with an orange wherewith to slake the thirst that will not be slow in coming. They lend me their good eyes and supple limbs. The expedition promises to be fruitful.
We soon discover high silk buildings, betrayed at a distance by the glittering threads which the dawn has converted into dewy rosaries. The children are wonderstruck at those glorious chandeliers, so much so that they forget their oranges for a moment. Nor am I, on my part, indifferent. A splendid spectacle indeed is that of our Spider's labyrinth, heavy with the tears of the night and lit up by the first rays of the sun. Accompanied as it is by the Thrushes' symphony, this alone is worth getting up for.
Half an hour's heat; and the magic jewels disappear with the dew. Now is the moment to inspect the webs. Here is one spreading its sheet over a large cluster of rock-roses; it is the size of a handkerchief. A profusion of guy-ropes, attached to any chance projection, moor it to the brushwood. There is not a twig but supplies a contact-point. Entwined on every side, surrounded and surmounted, the bush disappears from view, veiled in white muslin.
The web is flat at the edges, as far as the unevenness of the support permits, and gradually hollows into a crater, not unlike the bell of a hunting-horn. The central portion is a cone-shaped gulf, a funnel whose neck, narrowing by degrees, dives perpendicularly into the leafy thicket to a depth of eight or nine inches.
At the entrance to the tube, in the gloom of that murderous alley, sits the Spider, who looks at us and betrays no great excitement at our presence. She is grey, modestly adorned on the thorax with two black ribbons and on the abdomen with two stripes in which white specks alternate with brown. At the tip of the belly, two small, mobile appendages form a sort of tail, a rather curious feature in a Spider.
The crater-shaped web is not of the same structure throughout. At the borders, it is a gossamer weft of sparse threads; nearer the centre, the texture becomes first fine muslin and then satin; lower still, on the narrower part of the opening, it is a network of roughly lozenged meshes. Lastly, the neck of the funnel, the usual resting-place, is formed of solid silk.
The Spider never ceases working at her carpet, which represents her investigation-platform. Every night she goes to it, walks over it, inspecting her snares, extending her domain and increasing it with new threads. The work is done with the silk constantly hanging from the spinnerets and constantly extracted as the animal moves about. The neck of the funnel, being more often walked upon than the rest of the dwelling, is therefore provided with a thicker upholstery. Beyond it are the slopes of the crater, which are also much-frequented regions. Spokes of some regularity fix the diameter of the mouth; a swaying walk and the guiding aid of the caudal appendages have laid lozengy meshes across these spokes. This part has been strengthened by the nightly rounds of inspection. Lastly come the less-visited expanses, which consequently have a thinner carpet.
At the bottom of the passage dipping into the brushwood, we might expect to find a secret cabin, a wadded cell where the Spider would take refuge in her hours of leisure. The reality is something entirely different. The long funnel-neck gapes at its lower end, where a private door stands always ajar, allowing the animal, when hard-pushed, to escape through the grass and gain the open.
It is well to know this arrangement of the home, if you wish to capture the Spider without hurting her. When attacked from the front, the fugitive runs down and slips through the postern-gate at the bottom. To look for her by rummaging in the brushwood often leads to nothing, so swift is her flight; besides, a blind search entails a great risk of maiming her. Let us eschew violence, which is but seldom successful, and resort to craft.
We catch sight of the Spider at the entrance to her tube. If practicable, squeeze the bottom of the tuft, containing the neck of the funnel, with both hands. That is enough; the animal is caught. Feeling its retreat cut off, it readily darts into the paper bag held out to it; if necessary, it can be stimulated with a bit of straw. In this way, I fill my cages with subjects that have not been demoralized by contusions.
The surface of the crater is not exactly a snare. It is just possible for the casual pedestrian to catch his legs in the silky carpets; but giddy-pates who come here for a walk must be very rare. What is wanted is a trap capable of securing the game that hops or flies. The Epeira has her treacherous limed net; the Spider of the bushes has her no less treacherous labyrinth.
Look above the web. What a forest of ropes! It might be the rigging of a ship disabled by a storm. They run from every twig of the supporting shrubs, they are fastened to the tip of every branch. There are long ropes and short ropes, upright and slanting, straight and bent, taut and slack, all criss-cross and a-tangle, to the height of three feet or so in inextricable disorder. The whole forms a chaos of netting, a labyrinth which none can pass through, unless he be endowed with wings of exceptional power.
We have here nothing similar to the lime-threads used by the Garden Spiders. The threads are not sticky; they act only by their confused multitude. Would you care to see the trap at work? Throw a small Locust into the rigging. Unable to obtain a steady foot-hold on that shaky support, he flounders about; and the more he struggles the more he entangles his shackles. The Spider, spying on the threshold of her abyss, lets him have his way. She does not run up the shrouds of the mast-work to seize the desperate prisoner; she waits until his bonds of threads, twisted backwards and forwards, make him fall on the web.
He falls; the other comes and flings herself upon her prostrate prey. The attack is not without danger. The Locust is demoralized rather than tied up; it is merely bits of broken thread that he is trailing from his legs. The bold assailant does not mind. Without troubling, like the Epeirae, to bury her capture under a paralysing winding-sheet, she feels it, to make sure of its quality, and then, regardless of kicks, inserts her fangs.
The bite is usually given at the lower end of a haunch: not that this place is more vulnerable than any other thin-skinned part, but probably because it has a better flavour. The different webs which I inspect to study the food in the larder show me, among other joints, various Flies and small Butterflies and carcasses of almost-untouched Locusts, all deprived of their hind-legs, or at least of one. Locusts' legs often dangle, emptied of their succulent contents, on the edges of the web, from the meat-hooks of the butcher's shop. In my urchin-days, days free from prejudices in regard to what one ate, I, like many others, was able to appreciate that dainty. It is the equivalent, on a very small scale, of the larger legs of the Crayfish.
The rigging-builder, therefore, to whom we have just thrown a Locust attacks the prey at the lower end of a thigh. The bite is a lingering one: once the Spider has planted her fangs, she does not let go. She drinks, she sips, she sucks. When this first point is drained, she passes on to others, to the second haunch in particular, until the prey becomes an empty hulk without losing its outline.
We have seen that Garden Spiders feed in a similar way, bleeding their venison and drinking it instead of eating it. At last, however, in the comfortable post-prandial hours, they take up the drained morsel, chew it, rechew it and reduce it to a shapeless ball. It is a dessert for the teeth to toy with. The Labyrinth Spider knows nothing of the diversions of the table; she flings the drained remnants out of her web, without chewing them. Although it lasts long, the meal is eaten in perfect safety. From the first bite, the Locust becomes a lifeless thing; the Spider's poison has settled him.
The labyrinth is greatly inferior, as a work of art, to that advanced geometrical contrivance, the Garden Spider's net; and, in spite of its ingenuity, it does not give a favourable notion of its constructor. It is hardly more than a shapeless scaffolding, run up anyhow. And yet, like the others, the builder of this slovenly edifice must have her own principles of beauty and accuracy. As it is, the prettily-latticed mouth of the crater makes us suspect this; the nest, the mother's usual masterpiece, will prove it to the full.
When laying-time is at hand, the Spider changes her residence; she abandons her web in excellent condition; she does not return to it. Whoso will can take possession of the house. The hour has come to found the family-establishment. But where? The Spider knows right well; I am in the dark. Mornings are spent in fruitless searches. In vain I ransack the bushes that carry the webs: I never find aught that realizes my hopes.
I learn the secret at last. I chance upon a web which, though deserted, is not yet dilapidated, proving that it has been but lately quitted. Instead of hunting in the brushwood whereon it rests, let us inspect the neighbourhood, to a distance of a few paces. If these contain a low, thick cluster, the nest is there, hidden from the eye. It carries an authentic certificate of its origin, for the mother invariably occupies it.
By this method of investigation, far from the labyrinth-trap, I become the owner of as many nests as are needed to satisfy my curiosity. They do not by a long way come up to my idea of the maternal talent. They are clumsy bundles of dead leaves, roughly drawn together with silk threads. Under this rude covering is a pouch of fine texture containing the egg-casket, all in very bad condition, because of the inevitable tears incurred in its extrication from the brushwood. No, I shall not be able to judge of the artist's capacity by these rags and tatters.
The insect, in its buildings, has its own architectural rules, rules as unchangeable as anatomical peculiarities. Each group builds according to the same set of principles, conforming to the laws of a very elementary system of aesthetics; but often circumstances beyond the architect's control—the space at her disposal, the unevenness of the site, the nature of the material and other accidental causes—interfere with the worker's plans and disturb the structure. Then virtual regularity is translated into actual chaos; order degenerates into disorder.
We might discover an interesting subject of research in the type adopted by each species when the work is accomplished without hindrances. The Banded Epeira weaves the wallet of her eggs in the open, on a slim branch that does not get in her way; and her work is a superbly artistic jar. The Silky Epeira also has all the elbow-room she needs; and her paraboloid is not without elegance. Can the Labyrinth Spider, that other spinstress of accomplished merit, be ignorant of the precepts of beauty when the time comes for her to weave a tent for her offspring? As yet, what I have seen of her work is but an unsightly bundle. Is that all she can do?
I look for better things if circumstances favour her. Toiling in the midst of a dense thicket, among a tangle of dead leaves and twigs, she may well produce a very inaccurate piece of work; but compel her to labour when free from all impediment: she will then—I am convinced of it beforehand—apply her talents without constraint and show herself an adept in the building of graceful nests.
As laying-time approaches, towards the middle of August, I instal half-a-dozen Labyrinth Spiders in large wire-gauze cages, each standing in an earthen pan filled with sand. A sprig of thyme, planted in the centre, will furnish supports for the structure, together with the trellis-work of the top and sides. There is no other furniture, no dead leaves, which would spoil the shape of the nest if the mother were minded to employ them as a covering. By way of provision, Locusts, every day. They are readily accepted, provided they be tender and not too large.
The experiment works perfectly. August is hardly over before I am in possession of six nests, magnificent in shape and of a dazzling whiteness. The latitude of the workshop has enabled the spinstress to follow the inspiration of her instinct without serious obstacles; and the result is a masterpiece of symmetry and elegance, if we allow for a few angularities demanded by the suspension-points.
It is an oval of exquisite white muslin, a diaphanous abode wherein the mother must make a long stay to watch over the brood. The size is nearly that of a Hen's egg. The cabin is open at either end. The front-entrance broadens into a gallery; the back-entrance tapers into a funnel-neck. I fail to see the object of this neck. As for the opening in front, which is wider, this is, beyond a doubt, a victualling-door. I see the Spider, at intervals, standing here on the look-out for the Locust, whom she consumes outside, taking care not to soil the spotless sanctuary with corpses.
The structure of the nest is not without a certain similarity to that of the home occupied during the hunting-season. The passage at the back represents the funnel-neck, that ran almost down to the ground and afforded an outlet for flight in case of grave danger. The one in front, expanding into a mouth kept wide open by cords stretched backwards and forwards, recalls the yawning gulf into which the victims used to fall. Every part of the old dwelling is repeated: even the labyrinth, though this, it is true, is on a much smaller scale. In front of the bell-shaped mouth is a tangle of threads wherein the passers-by are caught. Each species, in this way, possesses a primary architectural model which is followed as a whole, in spite of altered conditions. The animal knows its trade thoroughly, but it does not know and will never know aught else, being incapable of originality.
Now this palace of silk, when all is said, is nothing more than a guard-house. Behind the soft, milky opalescence of the wall glimmers the egg-tabernacle, with its form vaguely suggesting the star of some order of knighthood. It is a large pocket, of a splendid dead-white, isolated on every side by radiating pillars which keep it motionless in the centre of the tapestry. These pillars are about ten in number and are slender in the middle, expanding at one end into a conical capital and at the other into a base of the same shape. They face one another and mark the position of the vaulted corridors which allow free movement in every direction around the central chamber. The mother walks gravely to and fro under the arches of her cloisters, she stops first here, then there; she makes a lengthy auscultation of the egg-wallet; she listens to all that happens inside the satin wrapper. To disturb her would be barbarous.
For a closer examination, let us use the dilapidated nests which we brought from the fields. Apart from its pillars, the egg-pocket is an inverted conoid, reminding us of the work of the Silky Epeira. Its material is rather stout; my pincers, pulling at it, do not tear it without difficulty. Inside the bag there is nothing but an extremely fine, white wadding and, lastly, the eggs, numbering about a hundred and comparatively large, for they measure a millimetre and a half (2). They are very pale amber-yellow beads, which do not stick together and which roll freely as soon as I remove the swan's-down shroud. Let us put everything into a glass-tube to study the hatching.
We will now retrace our steps a little. When laying-time comes, the mother forsakes her dwelling, her crater into which her falling victims dropped, her labyrinth in which the flight of the Midges was cut short; she leaves intact the apparatus that enabled her to live at her ease. Thoughtful of her natural duties, she goes to found another establishment at a distance. Why at a distance?
She has still a few long months to live and she needs nourishment. Were it not better, then, to lodge the eggs in the immediate neighbourhood of the present home and to continue her hunting with the excellent snare at her disposal? The watching of the nest and the easy acquisition of provender would go hand in hand. The Spider is of another opinion; and I suspect the reason.
The sheet-net and the labyrinth that surmounts it are objects visible from afar, owing to their whiteness and the height whereat they are placed. Their scintillation in the sun, in frequented paths, attracts Mosquitoes and Butterflies, like the lamps in our rooms and the fowler's looking-glass. Whoso comes to look at the bright thing too closely dies the victim of his curiosity. There is nothing better for playing upon the folly of the passer-by, but also nothing more dangerous to the safety of the family.
Harpies will not fail to come running at this signal, showing up against the green; guided by the position of the web, they will assuredly find the precious purse; and a strange grub, feasting on a hundred new-laid eggs, will ruin the establishment. I do not know these enemies, not having sufficient materials at my disposal for a register of the parasites; but, from indications gathered elsewhere, I suspect them.
The Banded Epeira, trusting to the strength of her stuff, fixes her nest in the sight of all, hangs it on the brushwood, taking no precautions whatever to hide it. And a bad business it proves for her. Her jar provides me with an Ichneumon (3) possessed of the inoculating larding-pin: a Cryptus who, as a grub, had fed on Spiders' eggs. Nothing but empty shells was left inside the central keg; the germs were completely exterminated. There are other Ichneumon-flies, moreover, addicted to robbing Spiders' nests; a basket of fresh eggs is their offspring's regular food.
Like any other, the Labyrinth Spider dreads the scoundrelly advent of the pickwallet; she provides for it and, to shield herself against it as far as possible, chooses a hiding-place outside her dwelling, far removed from the tell-tale web. When she feels her ovaries ripen, she shifts her quarters; she goes off at night to explore the neighbourhood and seek a less dangerous refuge. The points selected are, by preference, the low brambles dragging along the ground, keeping their dense verdure during the winter and crammed with dead leaves from the oaks hard by. Rosemary-tufts, which gain in thickness what they lose in height on the unfostering rock, suit her particularly. This is where I usually find her nest, not without long seeking, so well is it hidden.
So far, there is no departure from current usage. As the world is full of creatures on the prowl for tender mouthfuls, every mother has her apprehensions; she also has her natural wisdom, which advises her to establish her family in secret places. Very few neglect this precaution; each, in her own manner, conceals the eggs she lays.
In the case of the Labyrinth Spider, the protection of the brood is complicated by another condition. In the vast majority of instances, the eggs, once lodged in a favourable spot, are abandoned to themselves, left to the chances of good or ill fortune. The Spider of the brush-wood, on the contrary, endowed with greater maternal devotion, has, like the Crab Spider, to mount guard over hers until they hatch.
With a few threads and some small leaves joined together, the Crab Spider builds, above her lofty nest, a rudimentary watch-tower where she stays permanently, greatly emaciated, flattened into a sort of wrinkled shell through the emptying of her ovaries and the total absence of food. And this mere shred, hardly more than a skin that persists in living without eating, stoutly defends her egg-sack, shows fight at the approach of any tramp. She does not make up her mind to die until the little ones are gone.
The Labyrinth Spider is better treated. After laying her eggs, so far from becoming thin, she preserves an excellent appearance and a round belly. Moreover, she does not lose her appetite and is always prepared to bleed a Locust. She therefore requires a dwelling with a hunting-box close to the eggs watched over. We know this dwelling, built in strict accordance with artistic canons under the shelter of my cages.
Remember the magnificent oval guard-room, running into a vestibule at either end; the egg-chamber slung in the centre and isolated on every side by half a score of pillars; the front-hall expanding into a wide mouth and surmounted by a network of taut threads forming a trap. The semi-transparency of the walls allows us to see the Spider engaged in her household affairs. Her cloister of vaulted passages enables her to proceed to any point of the star-shaped pouch containing the eggs. Indefatigable in her rounds, she stops here and there; she fondly feels the satin, listens to the secrets of the wallet. If I shake the net at any point with a straw, she quickly runs up to enquire what is happening. Will this vigilance frighten off the Ichneumon and other lovers of omelettes? Perhaps so. But, though this danger be averted, others will come when the mother is no longer there.
Her attentive watch does not make her overlook her meals. One of the Locusts whereof I renew the supply at intervals in the cages is caught in the cords of the great entrance-hall. The Spider arrives hurriedly, snatches the giddy-pate and disjoints his shanks, which she empties of their contents, the best part of the insect. The remainder of the carcass is afterwards drained more or less, according to her appetite at the time. The meal is taken outside the guard-room, on the threshold, never indoors.
These are not capricious mouthfuls, serving to beguile the boredom of the watch for a brief while; they are substantial repasts, which require several sittings. Such an appetite astonishes me, after I have seen the Crab Spider, that no less ardent watcher, refuse the Bees whom I give her and allow herself to die of inanition. Can this other mother have so great a need as that to eat? Yes, certainly she has; and for an imperative reason.
At the beginning of her work, she spent a large amount of silk, perhaps all that her reserves contained; for the double dwelling— for herself and for her offspring—is a huge edifice, exceedingly costly in materials; and yet, for nearly another month, I see her adding layer upon layer both to the wall of the large cabin and to that of the central chamber, so much so that the texture, which at first was translucent gauze, becomes opaque satin. The walls never seem thick enough; the Spider is always working at them. To satisfy this lavish expenditure, she must incessantly, by means of feeding, fill her silk-glands as and when she empties them by spinning. Food is the means whereby she keeps the inexhaustible factory going.
A month passes and, about the middle of September, the little ones hatch, but without leaving their tabernacle, where they are to spend the winter packed in soft wadding. The mother continues to watch and spin, lessening her activity from day to day. She recruits herself with a Locust at longer intervals; she sometimes scorns those whom I myself entangle in her trap. This increasing abstemiousness, a sign of decrepitude, slackens and at last stops the work of the spinnerets.
For four or five weeks longer, the mother never ceases her leisurely inspection-rounds, happy at hearing the new-born Spiders swarming in the wallet. At length, when October ends, she clutches her offspring's nursery and dies withered. She has done all that maternal devotion can do; the special providence of tiny animals will do the rest. When spring comes, the youngsters will emerge from their snug habitation, disperse all over the neighbourhood by the expedient of the floating thread and weave their first attempts at a labyrinth on the tufts of thyme.
Accurate in structure and neat in silk-work though they be, the nests of the caged captives do not tell us everything; we must go back to what happens in the fields, with their complicated conditions. Towards the end of December, I again set out in search, aided by all my youthful collaborators. We inspect the stunted rosemaries along the edge of a path sheltered by a rocky, wooded slope; we lift the branches that spread over the ground. Our zeal is rewarded with success. In a couple of hours, I am the owner of some nests.
Pitiful pieces of work are they, injured beyond recognition by the assaults of the weather! It needs the eyes of faith to see in these ruins the equivalent of the edifices built inside my cages. Fastened to the creeping branch, the unsightly bundle lies on the sand heaped up by the rains. Oak-leaves, roughly joined by a few threads, wrap it all round. One of these leaves, larger than the others, roofs it in and serves as a scaffolding for the whole of the ceiling. If we did not see the silky remnants of the two vestibules projecting and feel a certain resistance when separating the parts of the bundle, we might take the thing for a casual accumulation, the work of the rain and the wind.
Let us examine our find and look more closely into its shapelessness. Here is the large room, the maternal cabin, which rips as the coating of leaves is removed; here are the circular galleries of the guard-room; here are the central chamber and its pillars, all in a fabric of immaculate white. The dirt from the damp ground has not penetrated to this dwelling protected by its wrapper of dead leaves.
Now open the habitation of the offspring. What is this? To my utter astonishment, the contents of the chamber are a kernel of earthy matters, as though the muddy rain-water had been allowed to soak through. Put aside that idea, says the satin wall, which itself is perfectly clean inside. It is most certainly the mother's doing, a deliberate piece of work, executed with minute care. The grains of sand are stuck together with a cement of silk; and the whole resists the pressure of the fingers.
If we continue to unshell the kernel, we find, below this mineral layer, a last silken tunic that forms a globe around the brood. No sooner do we tear this final covering than the frightened little ones run away and scatter with an agility that is singular at this cold and torpid season.
To sum up, when working in the natural state, the Labyrinth Spider builds around the eggs, between two sheets of satin, a wall composed of a great deal of sand and a little silk. To stop the Ichneumon's probe and the teeth of the other ravagers, the best thing that occurred to her was this hoarding which combines the hardness of flint with the softness of muslin.
This means of defence seems to be pretty frequent among Spiders. Our own big House Spider, Tegenaria domestica, encloses her eggs in a globule strengthened with a rind of silk and of crumbly wreckage from the mortar of the walls. Other species, living in the open under stones, work in the same way. They wrap their eggs in a mineral shell held together with silk. The same fears have inspired the same protective methods.
Then how comes it that, of the five mothers reared in my cages, not one has had recourse to the clay rampart? After all, sand abounded: the pans in which the wire-gauze covers stood were full of it. On the other hand, under normal conditions, I have often come across nests without any mineral casing. These incomplete nests were placed at some height from the ground, in the thick of the brushwood; the others, on the contrary, those supplied with a coating of sand, lay on the ground.
The method of the work explains these differences. The concrete of our buildings is obtained by the simultaneous manipulation of gravel and mortar. In the same way, the Spider mixes the cement of the silk with the grains of sand; the spinnerets never cease working, while the legs fling under the adhesive spray the solid materials collected in the immediate neighbourhood. The operation would be impossible if, after cementing each grain of sand, it were necessary to stop the work of the spinnerets and go to a distance to fetch further stony elements. Those materials have to be right under her legs; otherwise the Spider does without and continues her work just the same.
In my cages, the sand is too far off. To obtain it, the Spider would have to leave the top of the dome, where the nest is being built on its trellis-work support; she would have to come down some nine inches. The worker refuses to take this trouble, which, if repeated in the case of each grain, would make the action of the spinnerets too irksome. She also refuses to do so when, for reasons which I have not fathomed, the site chosen is some way up in the tuft of rosemary. But, when the nest touches the ground, the clay rampart is never missing.
Are we to see in this fact proof of an instinct capable of modification, either making for decadence and gradually neglecting what was the ancestors' safeguard, or making for progress and advancing, hesitatingly, towards perfection in the mason's art? No inference is permissible in either direction. The Labyrinth Spider has simply taught us that instinct possesses resources which are employed or left latent according to the conditions of the moment. Place sand under her legs and the spinstress will knead concrete; refuse her that sand, or put it out of her reach, and the Spider will remain a simple silk-worker, always ready, however, to turn mason under favourable conditions. The aggregate of things that come within the observer's scope proves that it were mad to expect from her any further innovations, such as would utterly change her methods of manufacture and cause her, for instance, to abandon her cabin, with its two entrance-halls and its star-like tabernacle, in favour of the Banded Epeira's pear-shaped gourd.
1. Or Bird Spiders, known also as the American Tarantula.
2. .059 inch.
3. The Ichneumon-flies are very small insects which carry long ovipositors, wherewith they lay their eggs in the eggs of other insects and also, more especially, in caterpillars. Their parasitic larvae live and develop at the expense of the egg or grub attacked, which degenerates in consequence.