Page:Popular Science Monthly Volume 6.djvu/665

Rh 2. —Like most geometrical spiders (Epeiridiæ), the Hyptiotes prefers to construct her net just before day. She is then less liable to interruption, and the newly-made net is best adapted for use in taking the builder's breakfast. To these early habits on the part of the spider is owing the fact that, although I have kept many of them in the house, I have never yet been so fortunate as to witness the entire process of net-making. Twice I sat up all night, but the spiders must have begun just as I fell asleep shortly before day; and my readers will understand that, in the midst of the fall term, a professor does not often feel able to spend a night in watching spiders.

However, I have twice witnessed the completion of nets, and have seen enough of the process to enable me, aided by what is known of spiders' methods in general, to infer how the net is begun and carried on, and the correctness of the following description may be accepted as at least probable, until disproved by actual observation of the entire process:

 Fig. 5.—a, last two segment of the hinder (fourth) leg of a female Hyptiotes; b, tip of the last segment, showing the claws open; c, cross-section of the last segment but one, showing its cavity, in which lie the muscles, and a single curved bristle upon the side, a part of the calamistrum; e, a similar bristle still more enlarged; d, f, two feathered bristles from near the joints.

Having first decided upon the general location of her net, the spider probably takes position head downward upon the "leeward" side of a twig or small branch, or upon its top, and then, turning her abdomen outward, expresses from her spinners a drop of gum, which instantly dries so as to form a fine end of a silken thread. This is taken by the wind (and careful experiments have proved that a current of air is absolutely necessary to the extension of the line) and wafted outward, waving from side to side, and usually tending up-ward from its extreme lightness, until at last it touches some other branch at a greater or less distance from the first. When this stoppage is perceived by the spider, she turns about and pulls in the slack line, until she is sure that the other end is fast. If it yields, she tries