$Amaurobius ferox.$--This lives in houses and is probably an imported species, as it is more common in Europe. It grows a little larger than _sylvestris_ (fig. 489), and the head is a little more narrowed in front of the legs. The colors and markings are much as in _sylvestris_, but the abdomen is often darker, and the middle light stripe on the front more distinct. The epigynum has a larger middle lobe, and the lateral lobes are straighter and do not meet in the middle. The males are colored like the females and have the thorax wider and the legs longer. The palpi of the male have the tarsus short and round. The tibia (fig. 492) has only a small short hook on the inner side, and a large blunt process on the outer side. The male palpi and the epigynum distinguish these easily from the last species. [Illustration: FIG. 493. Amaurobius americana, enlarged four times.] [Illustration: FIG. 494. Female Uloborus plumipes, enlarged eight times, showing the tuft of hairs on the front legs and the calamistrum on the fourth legs.] $Amaurobius (Titanœca) americana.$--Quarter of an inch long and deep black, except the cephalothorax, which is dull orange color, but covered, like the rest of the body, with long black hairs (fig. 493). Some individuals have a few light gray spots in pairs on the abdomen. The shape of the cephalothorax and abdomen are like _Amaurobius sylvestris_, and the legs are of the same proportional length and stouter. The palpi of the female have the tibia and tarsus a little thickened. The metatarsus of the fourth legs has the calamistrum more distinct than in others of the family, and the metatarsus appears thicker up and down than it is sidewise. The male has the legs longer, particularly the first pair, of which the tibia and metatarsus are more elongated than the other joints, and have many small spines on the under side. The male palpi have the tarsus large and round, supported by a wide and very complicated tibia. It lives under stones in the hottest and dryest places. [Illustration: FIG. 495. Horizontal web of Uloborus near the ground, one side attached to a fallen tree. The outer spiral is finished over only half the diameter of the web. A line of loose silk runs across the web, and in the middle is a peculiar zigzag spiral. The figure is about the real size.] [Illustration: FIG. 496. Web of young Uloborus in a raspberry bush. The lower half of the web is much wider than the upper. A band of silk runs across the middle and draws up with it some of the lower spirals. Half the real size.]