Adults are dark brown to black. Larvae are glossy brown and covered with brown setae at the margins; a brush of hairs projects at the end of the abdomen.
Development. Eggs are laid singly directly on the larval food, usually in late fall and winter. Hatching is in six to 22 days. Females lay about 70 eggs. Larval development is 269 to 639 days for males and 258 to 545 days for females. Males live about 40 days, and females live 15 to 38 days.
Habits. Larvae often crawl to the bottom of a food source or other substrate. When disturbed, larvae curl and remain motionless for along period. Larvae feed on silk cloth, wool, feathers, hair, fur, fishmeal, and cereal products; they often bore into stored food containers.