$Xysticus triguttatus.$--This is a small and very common spider living on grass and low bushes. The female is about a fifth of an inch long and the male as large but with a smaller abdomen. The difference in the color of the sexes is so great that they may easily be mistaken for different species. The females (fig. 95) are straw-colored, the abdomen almost white, and the thorax and legs brownish yellow. There are three black spots at the back of the thorax and indistinct darker bands at the sides. On the abdomen are two black spots near the front end and three pairs of broken transverse stripes behind. The male (fig. 96) has the femora of the two front legs dark brown, the rest like the female or a little darker. The thorax is dark brown, except in the middle, where it is a little lighter, as in the female. The abdomen of the male is strongly marked with transverse black and white stripes, irregular toward the front end. [Illustration: FIG. 98. Xysticus quadrilineatus, enlarged four times.] $Xysticus quadrilineatus.$--Quarter of an inch long, with the thorax a tenth of an inch wide and the head unusually wide in front. The color is light yellow, with light brown markings and black spots. The cephalothorax has four narrow brown stripes, one on each side close to the edge and the others running back from the lateral eyes (fig. 98); there are also two fine brown lines sometimes extending from the middle eyes to the dorsal groove, but usually broken in the middle. There is a brown spot just behind the dorsal groove and two others in the middle of the cephalothorax. On the abdomen there are two black spots at the front end, two in the middle and two near the hind end, besides several smaller ones along the sides. There are four light brown lines across the hinder half, each with a white line behind it, and at the sides are oblique brown lines alternating with white. The legs have a distinct light line along the dorsal side and are covered with fine brown spots without any other markings. [Illustration: FIGS. 99, 100. Xysticus versicolor.--99, female. 100, male. Both enlarged four times.] $Xysticus (Coriarachne) versicolor.$--The thorax, abdomen, and legs are all much flattened, the head is low, and the upper and lower eyes nearer together than in the other species. The colors are black and gray in irregular spots on a light ground (figs. 99, 100). On bark or unpainted wood these spiders can hardly be seen. Light individuals have black spots on the legs at the end of each joint and the usual three pairs of dark marks on the abdomen. On the thorax is a white spot in the middle under the front of the abdomen. Around this spot and behind the eyes is black extending in spots along the sides. In dark females and in most males the dark spots are so large that the whole spider is nearly black. This is a common spider, and a similar species, _Coriarachne depressa_, is equally common in Europe. THE GENUS PHILODROMUS