An irregular web of a curled-thread weaver is shown in [Fig. 104], from a photograph. In this web the framework is of ordinary silk; and upon this framework is placed a band of curled or tangled threads ([Fig. 105]). An insect alighting on a net of this kind is likely to get its feet caught in the tangled silk, and to be held fast till the spider can pounce upon it. Nets of this kind are found on bushes and on the sides of buildings.
There are two quite distinct types of regular webs made by spiders possessing a cribellum and a calamistrum. One is a round web which resembles at first sight those of the orb weavers; but it differs from the ordinary orb-web in that the spiral thread is made of curled or hackled silk. These webs are nearly horizontal, and are usually made between stones or in low bushes; they are not common.
Fig. 106. Web of the triangle spider.
The other type is represented by the web of the triangle spider. This web is most often found stretched between the twigs of a dead branch of pine or hemlock. At first sight it appears like a fragment of an orb-web ([Fig. 106]); but a little study will show that it is complete. The accompanying figure, by Dr. B. G. Wilder, who first described the habits of this spider ("Popular Science Monthly," 1875) illustrates the form of the web. It consists of four plain lines corresponding to the radiating lines of an orb-web, and a series of cross lines, which are spun by the cribellum and calamistrum. Each cross line is composed of two lines, about 1/500 of an inch apart. These double lines take the place of the curled threads woven by other members of the family to which the triangle spider belongs. From the point where the radiating lines meet, a strong line extends to one of the supporting twigs. Near this twig the spider rests, pulling the web tight so that there is some loose line between its legs, as shown in the enlarged figure. When an insect becomes entangled in one of the cross lines, the spider suddenly lets go the loose line so that the whole web springs forward, and the insect is entangled in other cross lines. The spider then draws the web tight and snaps it again. This may be repeated several times before the spider goes out upon the web after its prey.
The triangle spider is a tiny fellow, and so closely resembles the color of the dead branch near which it rests that it is very difficult to find; its web is more easily seen, though it usually requires careful searching to discover it.
The Motherhood of Spiders.
As a rule young spiders are forced to shift for themselves, and a very hard time they have; but of this we have not space to write. With spiders, the mother's care is devoted chiefly to furnishing protection to her helpless eggs. These are placed in silken sacs, which are often very elaborate in construction and protected with great care.
Fig. 107. Egg-sac of a spider.