Perhaps the most famous of America's spider species, the black widow can be found throughout Illinois, more commonly in the southern part of the state. Black widows are very poisonous, with a bite that can kill if treatment is not pursued immediately. Fortunately, black widows are not aggressive, requiring a great deal of disturbance before they'll bite. Black widows are small and black, with a distinctive red hour-glass shape on their underside.
This spider, usually between a half and three-quarters of an inch in length, can be found throughout the center of the United States. Brown, with thin legs, the brown recluse rarely bites. But if the spider is disturbed, such as when people push bare feet against a spider web inside a shoe, it might. Bites can be fatal but are most often minor irritants, only occasionally resulting in the necrotic rot most associated with the spider.
This common spider is found across the Midwest. Relatively large in size, the wolf spider has a stocky, hairy body. Brown in color, with darker stripes, the wolf spider hunts at night, leading to common sightings in homes, gardens and garages. The wolf spider's bite is poisonous and often painful but is unlikely to be deadly. Regardless, first aid should be sought immediately if bitten by a wolf spider.
Black House Spider
One of the more common sources of arachnid bites, black house spiders are found around window-frames, toilets, gutters and lights, which attract the spider's preferred prey. Black house spiders are about a half-inch in length, with thick bodies. Bites are never fatal, but some sufferers experience nausea or pain around the bite site.