The black widow spider, Latrodectus mactans,
is distinguished by a red hourglass marking on its underside.
Its venomous bite causes muscle spasms and difficulty in breathing.
The black widow, Latrodectus mactans, is a poisonous spider of the family Theridiidae, order Araneida. The female, about 1.3 cm (0.5 in) long, is glossy black, densely clothed with microscopic hairs, and marked with a characteristic red hourglass on the underside of the abdomen. The male, which is rarely seen, is smaller than the female and has four pairs of red marks along the sides of the abdomen. The black widow is found worldwide in the warmer regions in every state in the United States except Alaska and Hawaii; it lives in a variety of natural and domestic habitats. Generally, the females are not aggressive unless agitated, although they are prone to bite when guarding an egg sac. The venomous bite of the black widow spider, Latrodectus mactans, causes muscle spasms and breathing difficulty in humans and may be fatal. The female is distinguished by a red hourglass marking on its underside. The diet of the black widow consists of insects, spiders, and centipedes captured with its web. After mating, the female may ensnare and feed upon her mate--hence the name black widow.
