The epigynum varies in appearance according to the thickness and color of different parts. The two figures show common varieties (figs. 236, 237). This species and _longitarsus_ are both easily mistaken for _Amaurobius sylvestris_ and _ferox_, which are of the same size and color and live in the same situations. Amaurobius does not have the long upper spinnerets like Tegenaria, the eyes are lower on the front of the head, and there are larger light-colored markings on the front of the abdomen. The young of _Tegenaria medicinalis_ are pale, with light gray markings, and the cephalothorax is marked with spots radiating from the dorsal groove (fig. 234). The web of this spider is not flat like that of Agalena, but curved in various shapes according to the place where it is built. If there is an open level place near the nest, the web spreads across it, but usually curves upward at the edges and is fastened to surrounding stones and weeds. Where the spider lives in the cracks of a wall or rock, the net spreads along the surface of the rock, held away from it a short distance by threads fastened to projecting points on the stone (figs. 239, 240). This species is sometimes mistaken for the longer legged and more hairy _Tegenaria derhamii_ (fig. 228), that makes similar webs in barns and cellars. $Tegenaria (Cælotes) longitarsus.$--Smaller than _medicinalis_; about two-fifths of an inch in length. The head is very wide, and the mandibles of the female more swelled in front than in _medicinalis_, and the eyes are smaller and cover less than half the width of the head (figs. 244, 245). The cephalothorax is darker colored in front and does not have the two longitudinal stripes seen in _medicinalis_ (fig. 241). The legs are only faintly marked with gray in the middle of the joints. The abdomen is marked with gray, in a series of dark and light spots, as in other species, and of more regular shape than in _medicinalis_. The epigynum is light colored, with a middle bar covered with hair and slightly forked at the hinder end (fig. 242). The male differs in the usual way from the female and has the palpi shorter than _medicinalis_. The tarsus has a projection at the base that covers the tibia. The patella has a short process on the outer side that points directly forward (fig. 243). [Illustration: FIG. 239. Sections of webs of Tegenaria and Agalena.--_a_, Agalena nævia; _b_, common form of Tegenaria derhamii, with the edge lower than the tube; _c_, Tegenaria, with the edge higher than the tube; _d_, Tegenaria, with the edge carried up along the face of a rock; _e_, Tegenaria, with the edge carried down as well as up.] [Illustration: FIG. 240. Web of Tegenaria medicinalis, with the front edge carried up along the face of a rock. See diagram (fig. 239, _d_).]