That which, more than any thing else, distinguishes spiders from other animals is the habit of spinning webs. Some of the mites spin irregular threads on plants, or cocoons for their eggs; and many insects spin cocoons in which to pass through the change from larva to adult. In the spiders the spinning-organs are much more complicated, and used for a greater variety of purposes,—for making egg-cocoons, silk linings to their nests, and nets for catching insects. The spider’s thread differs from that of insects, in being made up of a great number of finer threads laid together while soft enough to unite into one.

SPINNERETS.

The external spinning-organs are little two-jointed tubes on the ends of the spinnerets, Fig. 1, L. Fig. 16 is the spinnerets of the same spider, still more enlarged to show the arrangement of the tubes. There is a large number of little tubes on each spinneret, and in certain places a few larger ones. Fig. 17 is a single tube, showing the ducta which leads the viscid liquid to form the thread from a gland in the spider’s abdomen. Each tube is the outlet of a separate gland. Fig. 18, a, shows four small tubes from a spinneret of Epeira, each with a small gland attached; and Fig. 18, b, a large tube, with one of the large glands which extends forward the whole length of the abdomen, Fig. 5, u.

The shape of the spinnerets, and size and arrangement of the tubes, vary in different species. Fig. 19 is a spinneret of Prosthesima, where there are a few large tubes in place of many small ones. In Agalena the two hinder spinnerets are long, and have spinning-tubes along the under side of the last joint, Fig. 20.

When the spider begins a thread, it presses the spinnerets against some object, and forces out enough of the secretion from each tube to adhere to it. Then it moves the spinnerets away; and the viscid liquid is drawn out, and hardens at once into threads,—one from each tube. If the spinnerets are kept apart, a band of threads is formed; but, if they are closed together, the fine threads unite into one or more larger ones. If a spider is allowed to attach its thread to glass, the end can be seen spread out over a surface as large as the ends of the spinnerets, covered with very fine threads pointing toward the middle, where they unite, Fig. 21.

The spinning is commonly helped by the hinder feet, which guide the thread, and keep it clear of surrounding objects, and even pull it from the spinnerets. This is well seen when an insect has been caught in a web, and the spider is trying to tie it up with threads. She goes as near as she safely can, and draws out a band of fine threads, which she reaches out toward the insect with one of her hind-feet; so that it may strike the threads as it kicks, and become entangled with them. As soon as the insect is tied tightly enough to be handled, the spider holds and turns it over and over with her third pair of feet, while, with the fourth pair, she draws out, hand over hand, the band of fine threads which adhere to the insect as it turns, and soon cover it entirely.

It is a common habit with spiders to draw out a thread behind as they walk along; and in this way they make the great quantities of threads that sometimes cover a field of grass, or the side of a house. We often see the points of all the pickets of a fence connected by threads spun in this way by spiders running down one picket, and up the next, for no apparent purpose.

Spiders often descend by letting out the thread to which they hang; and are able to control their speed, and to stop the flow of thread, at will. They sometimes hang down by a thread, and allow themselves to be swung by the wind to a considerable distance, letting out the thread when they feel they are going in the right direction.

Spiders in confinement begin at once to spin, and never seem comfortable till they can go all over their box without stepping off their web. The running spiders, that make no other webs, when about to lay their eggs, find or dig out holes in sheltered places, and line them with silk. Species that live under stones or on plants all line their customary hiding-places with web, to which they hold when at rest. Several of the large running spiders dig holes in sand, and line them with web, so that the sand cannot fall in; and build around the mouth a ring of sticks and straws held together by threads.

TRAP-DOOR NESTS.

The building of tubular nests is carried to the greatest perfection by certain genera of the MygalidÆ. (See page 13.)

Atypus, the most northern genus of this family, makes a strong silken tube, part of which forms the lining of a hole in the ground, and part lies above the surface, among stones and plants, Fig. 22, A. The mouth of the tube is almost always closed, at least when the spider is full grown.

Another genus, which lives in warm countries, makes tubes lined with silk, and closed at the top by a trap-door. A common species, Cteniza Californica, lives in the southern part of California, and is often brought east by travellers. It digs its hole in a fine soil, that becomes, when dry, nearly as hard as a brick; but the spider probably works when the ground is wet. The holes are sometimes nearly an inch in diameter, and vary in depth from two or three inches to a foot. The mouth is a little enlarged, and closed by a thick cover that fits tightly into it, like a cork into a bottle. The cover is made of dirt fastened together with threads, and is lined, like the tube, with silk, and fastened by a thick hinge of silk at one side, Fig. 22, B. When the cover is closed, it looks exactly like the ground around it. The spider holds on the inside of the door with the mandibles and the two front pairs of feet; while the third and fourth pairs of legs are pressed out against the walls of the tube, and hold the spider down so firmly, that it is impossible to raise the cover without tearing it.

Among the trap-door spiders of Southern Europe, about which Mr. J. T. Moggridge has written a very interesting book, are species which make different kinds of nests. The cover, instead of being thick, and wedged into the top of the tube like a stopper, is thin, and rests on the top of the hole, Fig. 22, C, and is covered with leaves, moss, or whatever happens to be lying about; so that it is not easily seen. Two or three inches down the tube is another door, Fig. 22, E, hanging to one side of the tube when not in use; but, when one tries to dig the spider out from above, she pushes up the lower door, so that it looks as if it were the bottom of an empty tube.

Another species digs a branch obliquely upward from the middle of the tube, closed at the junction by a hanging-door, which, when pushed upward, can also be used to close the main tube, Fig. 22, F. What use the spider makes of such a complicated nest, nobody knows from observation; but Mr. Moggridge supposes that when an enemy, a parasitic fly, for instance, comes into the mouth of the tube, the spider stops up the passage by pressing up against the lower door; but, if this is not enough, it dodges into the branch, draws the door to behind it, and leaves the intruder to amuse himself in the empty tube. The branch is sometimes carried up to the surface, where it is closed only by a few threads; so that, in case of siege, the spider could escape, and leave the whole nest to the enemy.

• Trap-door nests:
• A, nest of Atypus;
• B, nest with thick door;
• C, nest with thin door;
• D, branched nest;
• E, nest with two doors;
• F, branched nest with two doors;
• G, nest with two branches.

In these nests the spiders live most of the time, coming out at night, and some species in the daytime, to catch insects, which they carry into the tube, and eat. The eggs are laid in the tube; and the young are hatched, and live there till able to go alone, when they go out, and dig little holes of their own. As the spider gets larger, the hole is made wider, and the cover enlarged by adding a layer of earth and silk; so that an old cover is made up of a number of layers, one over the other, over the original little cover.

Moggridge once took a Cteniza Californica out of her nest, and put her on a pot of earth, and the next morning had the good luck to see her at work digging. She loosened the earth with her mandibles, and took it in little lumps with the mandibles and maxillÆ, and carried it away piece by piece. It took her an hour to dig a hollow as large as half a walnut. He saw the making of the door twice by other species. Once he dug a hole for a spider in some earth, and the next day found her in it, and the top covered by a little web, on which were scattered bits of earth and leaves, which had evidently been put there by the spider. The second night, enough dirt and silk were added to make the door of the usual thickness; but the spider never finished it so that it would open properly on its hinge. Another time Moggridge saw at the mouth of a very small hole a spider at work making a door. She spun a few threads across the hole, then gathered up with her front-legs and palpi an armful of dirt, and laid it on top of them. She then got under the pile, into the tube; but the motions of the dirt showed that she was still at work on it, and next morning the under side had been thickly covered with web, and the whole separated from the mouth of the tube, except at one side, where the usual hinge was left. The new door was at first soft, but in two or three days hardened, and appeared exactly like an old door.

These spiders are accustomed to put on the door moss like that which grows around it, and so conceal the door from sight; but when Mr. Moggridge took away the moss, and dug up the ground around a hole, and then destroyed the cover, the spider made a new one, and brought moss from a distance to put on it, thereby making it the most conspicuous thing in the neighborhood.

Mr. S. S. Saunders tried to see trap-door spiders make their nests. When the earth was dry, they would do nothing; but, after watering it, they several times dug new holes, but always in the night.

The food of the European trap-door spiders consists largely of ants and other wingless insects, and they have been known to eat earthworms and caterpillars. Mr. Moggridge has often seen them, even in the daytime, open their doors a little, and snatch at passing insects, sometimes taking hold of one too large to draw into the tube. One time he and some friends marked some holes, and went and watched them in the night. The doors were slightly open, and some of the spiders’ legs thrust out over the rim of the hole. He held a beetle near one of the spiders; and she reached the front part of her body out of the tube, pushing the door wide open, seized the beetle, and backed quickly into the tube again, the door closing by its own weight. Shortly after, she opened it again, and put the beetle out alive and unhurt, probably because it was too hard to eat. He next drove a sow-bug near another hole; and the spider came out and snatched it in the same way, and kept it. None of the spiders came entirely out of their holes, and they were only a little more active than in the daytime.

Erber, in the Island of Tinos, noticed a place where several trap-door nests were near each other, and spent a moonlight night watching them. Soon after nine o’clock some of the spiders came out, fastened back their doors, and each spun a web, about six inches long and an inch high, among the grass near her hole, and went back into the tube. In course of time beetles were caught in the webs, and eaten by the spiders, and the hard parts carried several feet from the nest. The next morning the webs had been cleared away, and the doors of the tubes closed, leaving no traces of the night’s work.

SILK TUBES AND NESTS.

Several species of Theridion and Epeira make tents near their webs, under which they hang when at rest, and in which some species make their cocoons, and lay their eggs. The tents are usually covered outside with leaves drawn together, with sticks or bud-scales collected near by, or with earth and stones brought up from the ground below.

Some spiders living on plants make flat tubes, in which they wait for insects, and also hide while moulting, or laying eggs. Others make, especially about the breeding-time, bags of silk on plants, or under stones, in which the egg-cocoons are finally spun.

Dolomedes makes among grass and shrubs, in meadows, a great nest, four or five inches in diameter, Fig. 23, in which is the egg-cocoon. The young hatch and ramble about in this nest for some time. The spider remains near, usually holding on under the nest.

THE WATER-SPIDER.

There is one spider that makes a bag of silk, something like those just mentioned, on water-plants, and lives in it under water, as in a diving-bell; the opening being below, so that the air cannot escape. Mr. Bell, in “The Journal of the LinnÆan Society,” vol. i., 1857, describes the filling of these nests with air by the spider. After the nest had been made as large as half an acorn, she went to the surface, and returned, fourteen times successively, and each time brought down a bubble of air, which she let escape into the nest. The bubble was held by the spinnerets and two hind-feet, which were crossed over them; and the method of catching it was the following: The spider climbed up on threads or plants nearly to the surface, and put the end of the abdomen out of water for an instant, and then jerked it under, at the same time crossing the hind-legs quickly over it. She then walked down the plants to her nest, opened her hind-feet, and let the bubble go.

The water-spiders run about on water-plants, and catch the insects which live among them. They lay their eggs in the nest; and the young come out, and spin little nests of their own, as soon as they are big enough. Their hairs keep the skin from becoming wet as they go through the water; and in the nest they are as dry as if it were under a stone, or in a hole on land.

COBWEBS.

The simple nests and tubes that have been described are made by spiders, most of which spin no other webs. The larger and better known cobwebs for catching insects are made by comparatively few species. On damp mornings in summer the grass-fields are seen to be half covered with flat webs, from an inch or two to a foot in diameter, which are considered by the weatherwise as signs of a fair day. These webs remain on the grass all the time, but only become visible from a distance when the dew settles on them. Fig. 24 is a diagram of one of these nests, supposed, for convenience, to be spun between pegs instead of grass. The flat part consists of strong threads from peg to peg, crossed by finer ones, which the spider spins with the long hind-spinnerets, Fig. 20, swinging them from side to side, and laying down a band of threads at each stroke. The web is so close and tight, that one can hear the footsteps of the spider as she runs about on it. At one side of the web is a tube leading down among the grass-stems. At the top the spider usually stands, just out of sight, and waits for something to light on the web, when she runs out, and snatches it, and carries it into the tube to eat. If any thing too large walks through the web, she turns around, and retreats out of the lower end of the tube, and can seldom be found afterward. In favorable places these webs remain through the whole season, and are enlarged, as the spider grows, by additions on the outer edges, and are supported by threads running up into the neighboring plants. Similar webs are made by several house-spiders, and are enlarged, if let alone, till they are a foot or two feet wide, and remain till they collect dirt enough to tear them down by its weight.

Nearly all spiders that make cobwebs live under them, back downward; and many are so formed, that they can hardly walk right side up. The spiders of the genus Linyphia make a flat or curved sheet of web, supported by threads above and below; the spider standing, usually, underneath in some corner, out of sight. Linyphia Marmorata makes a dome-shaped web, Fig. 25, supported by threads that extend up into the bushes two or three feet. The spider stands under the middle of the dome, where it draws in a small circle of web with its feet. The upper threads of the web interfere with the wings of small insects flying between them, and they fall down to the dome below, where they are seized, and pulled through the nearest hole. Linyphia communis makes a double web, Fig. 26. The spider stands under the upper sheet, which curves a little downward. What the use of the lower web is, is not easily seen. Either of these spiders, when frightened, leaps out of the web to the ground; but Linyphia communis must go to the edge before she can clear herself, and so is easily caught in her own web.

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A little spider, Argyrodes, belonging to the same family, lives among the upper threads of webs of this kind, without being troubled by the owner. It resembles in size and color the scales of pine-buds that often fall in the web, and may easily be mistaken for them. It probably spins a few threads of its own among the borrowed ones, and does, at times, make a separate web of its own.

The webs of Theridion usually have at some part a tent, or at least a thicker portion, under which the spider stands; and from this run irregularly simple threads, crossing each other in all directions, and held in place by threads above and below. Such irregular webs are made often in houses by Theridion vulgare, Hentz, in corners of rooms, under furniture, and in cellar-stairways. The same spider spins occasionally out of doors on fences, but never on plants. When it has caught an insect, and tied it up, it hoists it up into the web, sometimes a considerable distance.

They do this by fastening to it threads from above, which, as they dry, contract, and pull it up a little. They keep on bringing down more and more threads, until the insect is at last hoisted to the top of the web, where they can suck it without exposing themselves.

Pholcus, the long-legged cellar-spider, makes an irregular web of this kind, and has a curious habit when alarmed. It hangs down by its long legs, Fig. 27, and swings its body around in a circle, so fast that it can hardly be seen. Fig. 27, a, represents the spider as seen from below; and the dotted circle shows the path in which it revolves.

ROUND WEBS.

These well-known cobwebs are made by the family EpeiridÆ, Figs. 1, 4; and the process of making them by the common spider, from which these figures are drawn, can be easily observed in any garden. They generally choose for their web a window-frame or fence, or some such open wooden structure, where there is a hole or crack in which they can hide in the daytime.

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The spider begins by spinning a line across where the web is to be, and attaches another to it near the middle. She carries the last line along, holding it off with one of the hind-feet, and makes it fast an inch or two from one end of the first; then she goes back to the centre, attaches another line, which she carries off in another direction, and fastens; and so on, until all the rays of the web, Fig. 28, are finished. She stops occasionally at the centre, turns around, and pulls at the threads one after another, and spins here and there short cross-lines to hold them more firmly. She seems, by thus feeling the rays, to decide where to put in the next one, and does it always in such a way as to keep tight what has been done before. When the rays are finished to her satisfaction, the spider begins at the centre to spin a spiral line across them, Fig. 28, a, a, a; the turns of the spiral being as far apart as the spider can conveniently reach. She climbs across from one ray to the next, holding her thread carefully off with one of the hind-feet, till she gets to the right point, and then turns up her abdomen, and touches the ray with her spinnerets, thus fastening the cross-thread to it. The figure shows her in this position. When this spiral has been carried to the outside of the web, the spider begins there another and closer one, Fig. 28, of thread of a different kind. While the first thread was smooth, the latter is covered with a sticky liquid, which soon collects on it in drops, and makes it adhere to any thing that touches it. After going round a few times, this spiral crosses the one that was spun first, or would, if the spider allowed it to; but, as she comes to the old spiral, she bites it away, leaving only little rags, Fig. 22, b, attached to the rays, which may be seen in the finished web. By beginning thus at the outside, the spider is able to cover the whole web with adhesive threads, and, without stepping on it, take her usual place in the centre. She usually is careful enough to spin beforehand a thread from the centre to her nest, and sometimes stays there, with one foot on the thread, so as to feel if any thing is caught in the web. When she feels a shake, she runs down to the centre, feels the rays to see where the insect is, and runs out, and seizes it, or ties it up as described on page 43. We have described the web as consisting of one regular spiral; but this is seldom the case. It is usually wider on one side than the other, or below than above, as in Fig. 28, where outside the spirals are several loops going partly round the web. The web of Zilla consists entirely of such loops going three-quarters round the web, and returning, leaving a segment without any cross-threads, in which is the line from the centre to the spider’s nest, Fig. 29. The spider is shown carrying a fly to its nest attached to the spinnerets; and, if this is its usual habit, the web with an open segment is certainly more convenient than a complete one.

The web of Nephila plumipes, described by Wilder, consists also of loops running round about quarter of a circle, Fig. 30; and in this web the smooth cross-lines which are first spun are not removed, but remain after it is finished. Fig. 31 shows part of one side of a web; the arrows marking the smooth thread, and the direction in which it was spun.

Argiope, the large black and yellow autumn spiders, cross the middle of the web with a zig-zag band of white silk, which, as the web is obliquely hung, partly conceals the spider under it. These spiders also spin each side of the web, and two or three inches from it, a screen of irregular threads of unknown use.

The round-web spiders are said to repair their webs by tearing out a dirty, tangled piece, and putting a new one in its place. Wilder says that Nephila plumipes tears off and replaces half the web at one time. Epeira vulgaris often takes away an old web, and puts a new one in the same place, tearing down the old in pieces, and putting in the rays of the new as it goes along. The spider walks on the nearest sound thread, and gathers in with her front-feet as much old web as she can tear off, and rolls it up with her palpi and mandibles into a ball, and, when it is tight enough not to stick to the web, drops it. As she walks along, gathering up the old web in front, she at the same time spins a new thread behind, and, when she gets to a suitable place, makes it fast as one of the rays of the new web. The common story has it, that the spider eats the old web. She certainly gathers it up in her mouth, and sometimes throws it away at once, but at other times sits and chews it a long time, with apparent pleasure.

Most of the EpeiridÆ are brightly colored, and make no attempt at concealment when in the web. Others have odd shapes and colors, and hang in the web in such positions that they look like any thing but animals. Some species draw up their legs against their triangular abdomens, and look like bits of bark fallen into the web. Others are long and slender, and when at rest, either in the web or out, lay their legs close together before and behind their bodies, so as to look like straws. Others have oddly shaped abdomens, as Fig. 32, under which the rest of the body is partly concealed.

Epeira caudata, a common gray spider, living in the wood, collects pieces of insects and other rubbish, and arranges it in a line up and down, across the centre of the web. The spider stands in the centre, and from a short distance can hardly be distinguished from the rubbish. She also hides her cocoons in the web, in the same line of dirt.

The size of the web is usually proportioned to that of the spider; but Epeira displicata, which is quarter of an inch long, makes a web only two or three inches in diameter, on the ends of branches of bushes, where it is shaken about, and sometimes blown to pieces, by the wind.

As the spider stands in her web, and feels a slight shake, such as would be caused by a sudden wind, she draws her legs together, pulling the rays tighter, and so making the whole web steady. If, however, the spider is frightened, and has no time to escape, she throws her body back and forth as a man does in a swing, and thus shakes the web so rapidly, that the spider can hardly be seen. The most usual habit, when alarmed, is to drop to the ground, and lie there as if dead.

USE OF SPIDER’S SILK.

Various attempts have been made to use the silk of spiders, and chiefly that of the large round-web spiders, for practical purposes, either by carding the cocoons, or by drawing the thread directly from the spider. The latest experiments and plans for this purpose are those of Professor Wilder in “The Galaxy,” vol. viii. He shows how Nephila plumipes might be raised in large numbers, each spider kept by herself in a wire ring surrounded by water, fed with flies bred for the purpose from old meat, and milked every day of their thread. Each cocoon of this spider contains from five hundred to a thousand eggs. The young live together for two or three weeks, spin a web in common, and eat one another, or any small insects that come in their way. Then they begin to scatter, and each builds her own web; so that from this time they must be kept separate, or they would eat one another. Every day or two, each spider should be taken down, put into a pair of stocks, and the thread pulled out till it stops coming. In this way Wilder thinks an ounce of thread could be got from each spider during the summer. The thread is from a seven-thousandth to a four-thousandth of an inch thick, and much smoother and more brightly colored, as well as finer, than that of the silk-worm. Several threads would have to be twisted together to get one of manageable size. The principal difficulties are the space needed for keeping each spider by herself, and the amount of labor needed to provide them with living insects for food, and to draw out the silk, which would make it too expensive to use.

CURLED WEBS.

There is a family of spiders called by Blackwall CiniflonidÆ, see p. 17, which, besides the usual plain thread, make a peculiar kind of their own. They have in front of the spinnerets, Fig. 33, an additional spinning-organ called the cribellum, a, a. It is covered with fine tubes, much finer than those of the spinnerets, set close together.

They also have on the last joint but one of the hind-legs a comb of stiff hairs, called the calamistrum, Fig. 34, on the upper side.

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When they spin their peculiar web, they turn one of the hind-legs across under the spinnerets, so that the calamistrum is just under the cribellum, and the foot rests on the opposite leg, Fig. 35. The hind-legs are then moved rapidly back and forth; so that the calamistrum combs out from the spinning-tubes, and at the same time tangles a band of fine threads, C. This band is laid along, and attached here and there to a plain thread, A, B, so as to make it adhere more readily to an insect that happens to touch it. As one leg gets tired, they change, and work with the other. In the webs of these spiders this adhesive band can be seen with the naked eye, running about, as in Fig. 36. The webs are usually irregular, and shaped to fit the place where they are built, but have, in some part, a tube somewhat like that of the grass spider, Fig. 24, where the owner hides. Sometimes they are more or less regular in structure, some of the threads being parallel, and crossed by shorter ones at regular intervals, Fig. 37. Others are circular, with a tube in the centre which runs into a crack, and from which radiate irregularly the principal threads of the web. Such webs are sometimes very numerous on stone buildings, and, as they collect large quantities of dust, seriously disfigure them. The webs alone, when clean, would not be noticed.

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THE TRIANGLE SPIDER.

Among those spiders that use the calamistrum is one which makes a web unlike any other. It has been described by Professor Wilder, in the “Popular Science Monthly” for April, 1875, under the name of the “triangle spider.” It lives usually among the dead branches around the lower part of pine and spruce trees, and is colored so like the bark, that when it stands, as it usually does, on the end of a branch, it is easily mistaken for a part of it. The web seems to be made in the night. Wilder saw them early in the morning; and I, in the evening, between sunset and dark. A single thread five or six inches long runs from the spider’s roost; and from its extremity radiate four branches, attached to various twigs in the neighborhood, Fig. 38, AE, AF, AG, AH.

The spider begins to cross them with adhesive threads near the end of the upper ray at S'. After fastening the end of the thread, she walks along toward the centre, scratching away all the time with her calamistrum, till she comes to a place, 5, where she can cross to the next ray. She crosses over, and goes outward toward S, the thread shrinking as she goes, until, when she arrives at S, it is just long enough to reach across to S'. She fastens it by laying it along the ray for a short distance, and goes inward again till she reaches 7, where she crosses to the next ray; and so on till the thread is finished to S?'. Here she stops spinning, and goes up the lower ray to A, and along the upper one to 4, where she starts another cross-thread. This goes on till the whole web is filled, as in Fig. 39, nearly to the centre.

When the web is finished, the spider goes up the thread A o, to within an inch or so of the twig to which it is fastened; turns round, and takes hold of the thread with her front-feet; then pulls herself backward with her hind-feet up to the twig. She thus tightens the web, and draws up a loop of thread between her front and hind feet, Fig. 39, lower figure.

The net is now set for use, and she stands holding it till something touches it; then she lets go with her hind-legs, and the net springs forward, bringing more threads into contact with the insect, and sliding the spider along the line toward A. If she thinks it worth while, she draws up another loop, and snaps the web again. When she is satisfied that the insect is caught, she gathers up part of the web till she comes to him, covers him with silk, and carries him up to her roost.

There are other spiders of this group that make round webs, just like those of the EpeiridÆ, Fig. 28, except in the adhesive threads being spun with the calamistrum.

FLYING SPIDERS.

Often, in summer, the bushes are covered with threads, attached by one end, blowing out in the wind; and bits of cobweb are blowing about, with occasionally a spider attached. To account for such threads, curious theories have been thought of; among others, that spiders are able to force the thread from their spinnerets, like water from a syringe, in any direction they choose.

If a spider be put on a stick surrounded by water, she manages, in course of time, to get a thread to some object beyond, and to escape by it. To find out how this is done, Mr. Blackwall tried some experiments. He put spiders on sticks in vessels of water, and they ran up and down, unable to escape as long as the air in the room was still. But, if a draught of air passed the spider, she turned her head toward it, and opened her spinnerets in the opposite direction. If the draught continued, a thread was drawn out by it, which at length caught upon something, when the spider drew it tight, and escaped on it. If the air was kept still, or the spider covered with a glass, she remained on the stick till taken off.

These experiments have been repeated, and show that the spider does not shoot or throw the web in any way, but takes advantage of currents of air, and allows threads to be blown out to a considerable distance.

There is a still more curious use of this method of spinning threads; that is, in flying. Small spiders, especially on fine days in the autumn, get up on the tops of bushes and fences, each apparently anxious to get as high as possible, and there raise themselves up on tiptoe, and turn their bodies up, as in Fig. 40, with their heads toward the wind, and spinnerets open. A thread soon blows out from the spinnerets, and, if the current of air continues, spins out to a length of two or three yards, and then offers enough resistance to the wind to carry the spider away with it up into the air. As soon as she is clear, the spider turns around, and grasps the thread with her feet, and seems to be very comfortable and contented till she strikes against something. Sometimes they rise rapidly, and are soon out of sight; at other times blow along just above the ground.

This habit is not confined to any particular kinds of spiders, but is practised by many small species of Erigone, and by the young of many spiders of all families, that, when adult, would be too large for it. The majority of the spiders flying in autumn are the young of several species of Lycosa, that seem to spend the greater part of October and November trying to get as far above ground as possible. The best places to watch them are garden-fences in cities, where they often swarm, and can be more distinctly seen than on bushes. Large numbers can always be seen, for example, on the fences around the Common in Boston, every fine day in autumn, until there has been a long period of cold weather. Other species fly in the early part of summer.

Mr. Blackwall observed in Manchester, Eng., Oct. 1, 1826, a calm sunny day, that, just before noon, the fields and hedges were covered over with cobwebs. So thick were they, that, in crossing a small pasture, his feet were covered with them. They had evidently been made in a very short time, as early in the morning they were not conspicuous enough to attract his attention, and the day before could not have existed at all, as a high wind blew all day. At the same time large rags of web were floating about in the air, one measuring five feet long, and several inches wide. These appeared to be not formed in the air, but torn from grass and bushes, where they were produced by the tangling of many threads which had been spun separately. They kept rising all the forenoon, and in the afternoon came down again. Not one in twenty had a spider on it. Similar large webs were observed by Lincecum in Texas, and supposed by him to be balloons spun purposely by the spiders.

Mr. Darwin, in the journal of the voyage of “The Beagle,” says, that when anchored in the River Plata, sixty miles from shore, he has seen the rigging covered with cobwebs, and the air full of pieces of web floating about. The spiders, however, when they struck the ship, were always hanging from single threads, and never to the floating webs.

A recent account of the signs of weather-changes near the southern coast of the United States mentions as one of them cobwebs in the rigging.

It is still unexplained how the thread starts from the spinnerets. It has been often asserted that the spider fastens the thread by the end, and allows a loop to blow out in the wind; but, in most cases, this is certainly not done, only one thread being visible. Sometimes, while a thread is blown from the hinder spinnerets, another from the front spinnerets is kept fast to the ground, Fig. 41; so that, when the spider blows away, it draws out a thread behind it entirely independent of the one from which it hangs.

Fig. 41.