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.