$Mimetus interfector.$--This is about the same size and color as _Theridium tepidariorum_, but it has a round and Epeira-like abdomen and spiny legs like Epeira or Linyphia. The length is nearly a quarter of an inch. The cephalothorax is one and a half times as long as wide, widest behind and narrow in front (fig. 314). The mandibles are long and dark colored, except a spot near the base. The cephalothorax is whitish, with a stripe of brown from the eyes to the dorsal groove. The abdomen is small, widest in front, like that of _Epeira angulata_, with two prominent corners. The markings are also like Epeira,--a central stripe, with dark spots along the edges (figs. 314, 315). The color is gray and brown in the darker parts. The legs are light yellow, with dark rings at the ends of the joints. It lives on bushes and occasionally on houses and fences, where it has been found in webs among those of _Theridium tepidariorum_. [Illustration: FIGS. 316, 317. Ero thoracica.--316, back of female enlarged eight times. 317, side of female.] $Ero thoracica.$--This spider resembles the young of _Theridium tepidariorum_, but the colors are brighter, and the hairs longer and coarser. It is an eighth to a sixth of an inch long. The cephalothorax is nearly as high in the middle as it is long and slopes at a sharp angle under the front of the abdomen (fig. 317). The head is lower than the middle of the thorax, and the front middle eyes project beyond the mandibles. The abdomen is as high as long and has a pair of humps on the highest part. The cephalothorax is light yellow, with a dark irregular stripe on each side and a middle line crossed by a crescent-shaped mark on the highest part. The abdomen is white, with brown spots of various shapes. The front half of each hump is dark brown, and a dark line extends from there down the sides (fig. 316). At the back of the abdomen are several transverse stripes, which are sometimes reddish. Stiff brown hairs are scattered all over the abdomen. The legs are ringed with brown and yellow, and have coarse brown hairs and long spines on the tibia and tarsus, which is unusual in this family. It is found under stones and in winter under leaves in woods. It lives also in Europe. THE LINYPHIADÆ