Although spiders in general produce venom with which to paralyze their prey, only a very few have fangs of sufficient length or power to penetrate human skin, or venom of sufficient quantity or potency to affect human health. There are two poisons present in spider venom: a toxin which cause local symptoms, and a toxalbumin producing general symptoms. In those spiders whose bites produce systematic disturbances it is believed that the latter poison predominates. Where black widows live Black widows spin their webs in crevices between rocks, under logs or overhanging banks, in abandoned rodent holes, and in rock and wood piles. Indoors they are most frequently encountered in dark corners of garages, basements, and stables. [Illustration: _Underside of black widow spider showing characteristic red “hourglass” mark on the abdomen by which this species may be recognized._] A favorite and especially dangerous location in which a black widow establishes her home is beneath the seat of a pit toilet. Such a location is ideal for the spider because it is dark, is not usually disturbed, and insects, especially flies, upon which the spiders feed, are abundant. Humans using the toilet, unaware of the presence of the spider, arouse her by breaking or agitating her web, and offer especially tender and susceptible portions of their anatomies for her bite. Pit toilets in warm climates should always be built with hinged seats which should be raised and inspected frequently. As a further precaution, the underside of the seats should be treated with creosote, an effective repellent. Although the majority of people now recognize the black widow, some do not, hence they kill all dark-colored spiders on general principles. This is neither necessary nor desirable. The female black widow is a medium-sized, glossy black, solitary spider with a globular abdomen spectacularly marked on the underside with a bright red spot roughly the shape of an hourglass. The normal position of the spider is hanging upside down in her web so that the “hourglass” is plainly visible if she is below the level of the eye. Her overall length is 1 to 1¼ inches. The males are much smaller and, like the immature females, are grey in color and variously striped and spotted. Adult females spin egg cocoons during the warm season; each cocoon contains approximately 300 to 500 eggs which hatch in about 30 days. As many as nine broods per year have been recorded. The young grow fast but do not mature until the following spring or summer. Black widow bites Although black widows ferociously pounce upon insects or other spiders much larger than themselves which become entangled in their webs, they are by nature retiring and bite humans only when restrained from escape by contact with the body of man.