This group comprises several families that differ greatly in form and habits, but agree in having peculiar spinning organs, different from those of all the other spiders. They have the usual six spinnerets and in addition the cribellum (fig. 469), a flat, wide spinning organ, close in front of the other spinnerets and covered with finer spinning tubes. Besides this additional spinning organ they have on the hind legs the calamistrum (fig. 470), a row of hairs that is used to draw out a loose band of silk from the spinnerets. Most of our species belong to the genera Dictyna and Amaurobius and resemble Tegenaria (pp. 96-99) in their feet with three claws, in the arrangement of the eyes, and in their general form and color. The others belong to the small and peculiar genera Filistata, Hyptiotes, and Uloborus. [Illustration: FIG. 471. Webs of Dictyna on the side of a house. The nests were in the groove between the boards, and the webs radiated irregularly from them, crossing each other in all directions so as to appear like parts of one web.] [Illustration: FIG. 472. Web of Dictyna in the corner of a window pane.] THE GENUS DICTYNA The Dictynas are all small spiders, not more than a sixth of an inch in length, but are brightly colored and live in webs in open places, where they cannot fail to be seen by any one who looks for spiders. They are not easily frightened, and so their habits can be more easily watched than those of many larger kinds. The heads are high, arching up from the eyes to the highest part opposite the first legs (fig. 476). The eyes are higher and the front of the head is more nearly vertical than in Amaurobius (fig. 489). The head is about half as wide as the thorax and distinctly marked off from it and usually lighter colored. The abdomen is sometimes marked with light yellow on a gray ground, as in Amaurobius, or with a light middle stripe of various shapes, bordered with brown or gray (fig. 487). The whole body is covered with fine hairs, and there are often long white hairs in rows on the cephalothorax. The cribellum is large for the size of the spiders and can generally be plainly seen just in front of the other spinnerets. The calamistrum is not so easy to see, but it covers about half the length of the fourth metatarsus. The peculiarities of the species of these spiders are more strongly marked in the males. The mandibles of both sexes are long and a little curved forward at the ends (fig. 476), but in the males they are sometimes so long that the distance from the ends of the mandibles to the top of the head is as great as the length of the cephalothorax, and the lower ends are turned forward at a sharp angle with the upper part. The mandibles of the males are curved apart in the middle, and they have at the base a short tooth projecting forward (fig. 477). The palpi of the males have a process on the tibia, usually near the base, on the end of which are two spines (fig. 478). There is not