Best Spider Identification Guides to Buy in October 2025
Spiders of North America (Princeton Field Guides)
Common Spiders of North America
Spiders of the United States & Canada: Easily Identify 158 Common Species (Adventure Quick Guides)
National Wildlife Federation Field Guide to Insects and Spiders & Related Species of North America
Spiders of North America: An Identification Manual, Second Edition
National Audubon Society Field Guide to Insects and Spiders: North America (National Audubon Society Field Guides)
Backyard Bugs: An Identification Guide to Common Insects, Spiders, and More
Illinois is home to two species of poisonous spiders: the black widow and the brown recluse. The black widow is a shiny black spider with a red hourglass shape on its abdomen. Its venom is toxic to humans and can cause muscle cramps, spasms, and other symptoms. The brown recluse is light to dark brown in color with a violin-shaped marking on its back. Its venom can cause tissue necrosis and other serious health issues. While these spiders are present in Illinois, bites are rare and can usually be treated with prompt medical attention.
How many non-lethal spider bites occur in Illinois?
There is no specific data available on the exact number of non-lethal spider bites that occur in Illinois. However, most spider bites in Illinois are non-lethal and do not require medical attention.
How many different species of poisonous spiders are found in Illinois?
There are four different species of poisonous spiders found in Illinois: the black widow spider, brown recluse spider, woodlouse spider, and yellow sac spider.
What is the most dangerous species of poisonous spider in Illinois?
The most dangerous species of poisonous spider in Illinois is the brown recluse spider (Loxosceles reclusa). The bite of a brown recluse spider can cause severe damage to skin tissue and can lead to necrosis, a condition where the tissue dies. Though bites are rare and fatalities are extremely rare, it is important to seek medical attention if bitten by a brown recluse spider.