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.
Fig. 27.
Fig. 28.
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.
Fig. 29.
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.
Fig. 30.
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.
Fig. 31.
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.
Fig. 32.
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.