Public Health Importance . Her underside has a red to orange hour-glass shaped mark. The venom of the black widow contains a neural poison. Strong abdominal cramps, sweating, and nausea are symptoms of a bite. If someone is bitten by a spider, a physician should be consulted and if possible the offending spider brought to him for inspection.
Black widows inhabit dark corners and spin loose, random webs.
Another spider to avoid is the brown recluse, Loxosceles reclusa Gertsch and Malaik. The cotton-like web of the brown recluse is found in very secluded areas, usually indoors. The spiders spend all their time in the web except when the mature male leaves to search for a mate. The male brown recluse spider is similar in appearance to the female and only slightly smaller. Once mating takes place the female lays eggs in a silken sac.