$Lycosa nidifex.$--This spider lives in sandy regions,--the females in holes ten or twelve inches deep, the adult males on the surface of the ground. The males (fig. 174) are half or five-eighths of an inch long and spread two inches. They are colored like the sand,--a little redder sometimes in the middle spots and on the femora, and gray at the sides. There is a spot in the middle of the abdomen edged with black and a black band on each side of the head divided in front, the branches extending to the lateral eyes of both rows. The ends of the palpi and the spinnerets are black. The mandibles are black, except in the middle, where they are covered with bright yellow hairs. On the under side (fig. 175) the two front pairs of legs, sternum, and mouth parts are black, the hinder legs and abdomen light sand color, like the back. The female (fig. 173) is larger,--three-quarters of an inch or more in length. The color is more gray or slate color, darker in front and lighter behind, as in the male. The cephalothorax has a light gray band in the middle, and the abdomen a middle dark band broken at the sides by three or four pairs of light spots. The front two pairs of legs are thicker than the others and more closely covered with hair in both sexes. [Illustration: FIG. 173. Lycosa nidifex.--Female enlarged twice.] [Illustration: FIGS. 174, 175. Lycosa nidifex.--174, back of male. 175, under side of male. Both enlarged twice.] In August the males wander about on the sand and are easily caught. Though their color is much like the sand, the marks of the back and legs make them more easily seen than _L. cinerea_ (fig. 177) and other sand spiders. The females live in holes three-quarters of an inch wide and ten inches or more deep. The sand is held together by silk, which is very thin below but thicker toward the opening. Sometimes bits of sticks and straw are fastened around the hole, but as often it is entirely clean and not concealed in any way. The females keep near their holes and drop into them at the least fright. As one walks across the neighborhood no spiders are to be seen, only open holes. After a short time they come to the surface, at first slowly, but sometimes, as they see the place clear, with a sudden jump, and stand over the hole ready to drop back into it. The color of the females is more gray or slate color than that of the males. The markings of the abdomen are larger and more distinct, but the black on the thorax and front legs is less marked than in the males. [Illustration: FIG. 176. Lycosa carolinensis.--Under side of female to show the black markings.]