The brown recluse is a small, light brown to yellow, quite harmless-looking spider. Its slim body is about 3/8 inch long with long legs that extend its length to more than 1 inch. The primary key to identification is the arrangement of the three pairs of eyes. The "fiddle"- or "violin"-shaped outline on the back is not a dependable character since many brown spiders have similar markings. The male brown recluse is similar in appearance to the female except it has a smaller abdomen and large knob-like palpi on the front of the head.
The brown recluse spider sometimes lives for two years. Mating usually occurs in June and July. One mating is sufficient for the female to produce 30 to 300 offspring. The brown recluse is a shy spider and searches for its insect prey primarily at night. During the day it rests in closets, boxes, under furniture, in attics under insulation and in ceiling light fixtures. People typically are bitten accidentally while putting on clothes in which the spider is hiding or by rolling onto them while in bed.