$Latrodectus mactans.$--This is the largest spider of the family. It is sometimes half an inch long, with the abdomen round and the whole body black, except a bright red spot underneath and one or more red spots over the spinnerets and along the middle of the back (figs. 289, 290). The spots turn yellow or white in alcohol. The cephalothorax is about as wide as long, and the grooves between the head and thorax are deep. The lateral eyes are farther apart than usual in this family. The legs of the male are much larger than those of the female, and each joint is orange brown in the middle and black at the ends. The abdomen of the male has a row of red and white spots in the middle line, as some females do, and across the front end, and along the sides four pairs of stripes, red in the middle and white at the edges (fig. 291). The young of both sexes are colored somewhat like the male and, when very small, have very little black on them. The males vary much in size, some being only a quarter as large as the female. This spider makes its nest among loose stones, on plants, or in houses. Around its hiding place it spins a large funnel-shaped tent that widens into a flat or curved sheet of web, closer in texture toward the tube and more open toward the edges, spreading two or three feet over plants and stones. It is found all over the United States, as far north as Massachusetts and New Hampshire and south through Florida, the West Indies, and South America, as far as Chile. It is everywhere feared as poisonous and dangerous, probably on account of its large size and conspicuous colors, as there is no good reason for considering it more poisonous than other spiders. [Illustration: FIGS. 292, 293, 294, 295. Argyrodes trigonum.--292, side of female enlarged eight times, the dotted line showing the abdomen bent downward. 293, tip of abdomen seen from above. 294, top of cephalothorax. 295, cephalothorax of male.] [Illustration: FIG. 296. Web of Argyrodes trigonum between two maple leaves. In the middle of the web are two egg cocoons and above them the spider.]