These spiders get their name from the popular belief that the female eats the male after mating, which rarely happens in nature. 5 species occur in the United States, with the “Western Widow” (Latrodectus Hesperus) occurring in the western United States and Western Canada (see map), but not west of the Cascade Mountains in Washington State.
The adult female black widow is about 1/2″ in diameter, with an overall length including legs of about 1 1/2″. They are typically black with 2 reddish triangular markings joined to form an hourglass on the underside of the abdomen. Males are about half the size of females without the hourglass marking.
Black widows commonly live in protected places under pieces of wood, in woodpiles, under decks, stumps, in rodent burrows, and sometims in shrubs. They favor dry, man-made structures like barns, sheds, meter boxes, and woodpiles. Inside, they are often found in less frequented areas such as garages, basements, and crawlspaces. Black widow webs are not geometric and orderly, but rather an irregular tangle of strands with no pattern.