Page:Popular Science Monthly Volume 1.djvu/697

Rh two or three radii spun from its centre, than she continues her labor so quickly and unremittingly that the eye can scarcely follow her progress. The radii, to the number of about twenty, giving the net the appearance of a wheel, are speedily finished. She then proceeds to the centre, quickly turns herself round, and pulls each thread with her feet to ascertain its strength, breaking any one that seems defective and replacing it by another. Next, she glues immediately round the centre five or six small, concentric circles, close to each other, and then four or five larger ones, each separated by a space of half an inch or more. These last serve as a sort of temporary scaffolding to walk over, and to keep the radii properly stretched while she glues to them the concentric circles that are to remain, which she now proceeds to construct. Placing herself at the circumference, and fastening her thread to the end of one of the radii, she walks up that one toward the centre, to such a distance as to draw the thread from her body of a sufficient length to reach to the next; then stepping across, and conducting the thread with one of her hind-feet, she glues it with her spinners to the point in the adjoining radius to which it is to be fixed. This process she repeats until she has filled up nearly the whole space from the circumference to the centre with concentric circles, distant from each other about the sixth of an inch. Besides the main web, the spider sometimes carries up from its edges and surface a number of single threads, often to the height of many feet, joining and crossing each other in various directions. Across these lines, which may be compared to the tackling of a ship, flies seem unable to avoid directing their flight. The certain consequence is that, in striking against these ropes, they become slightly entangled, and, in their endeavors to disengage themselves, rarely escape being precipitated into the net spread underneath for their reception, where their doom is inevitable."

The weaving-spider that is found in houses having selected a suitable site, in the same way forms first the margin or selvage of her web. From these she draws other threads, the spaces between which she fills up by running from one to the other, and connecting them by new lines, until the gauze-like texture is formed. The spider seems to be aware that she is no beauty, and had better conceal herself; so she constructs a small silken apartment, completely hidden from view, in which she lies in wait for her victims. But as this is often at a distance from the net, and entirely out of sight of it, how is she to know when an insect is caught? To meet this emergency, she spins several threads from the edge of the net to that of her hole, which answers as a telegraph by its vibrations, and is a railroad over which she can pass to secure it.

In their vital physiology spiders are quite as wonderful as in their other characters. We have said that they do not undergo metamorphoses, like insects, but the common household spider, which we have