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Welcome to the Project!

Goals of the Project Ken Cramer at Monmouth College is continuing a long-term project to determine the distribution of the brown recluse spider in northern Illinois and southern Iowa.  Because of the medical importance of the spider, we hope a more precise understanding of their distribution will help professionals and the public avoid misdiagnoses and misidentifications.  A second goal of the project is to provide accurate, up-to-date scientifically verified information on the brown recluse spider. The navigation bar at left offers general information on brown recluses that may be of interest to the general public.  Dr. Cramer is an arachnologist (a scientist who studies spiders), not a physician and he does not offer diagnoses of skin lesions or other medical conditions (see "Bite Diagnoses").

The natural northern distribution limit of brown recluses occurs in central Illinois (see “Map – Where Are They?” on the navigation bar at left) and southern or central Iowa. A few isolated brown recluse specimens have been recorded from the greater Chicago metropolitan area and southern Wisconsin. Only a handful of localities in Chicago (single buildings) have confirmed recluse spiders in the past 5 years.  If you suspect you have brown recluses after reviewing the photos on this web page, please send me a specimen for verification. To more precisely document where the brown recluse lives in northern Illinois, Wisconsin, and southern Iowa, we are requesting the participation of as many interested parties as possible to send us spiders for identification.

Help with our study
We want your spiders!
We are especially interested in spiders collected in the Illinois/Iowa area.  If you live in Illinois, we are soliciting spiders collected in northern Illinois, particularly north of highway I-70, or north of a line running East-West through East St. Louis.  If you live anywhere in Iowa, we want your house spiders.  This study is ongoing -- if you encounter this web site, we still want your spiders. If you live outside of Illinois or Iowa and think you might have a brown recluse, feel free to send me your spider and I will identify it for you. If you live in Indiana or Ohio, visit this page and support Brian Foster's project documenting the distribution of recluses in those states: Please send any spiders (more on mailing spiders) for this study to Dr. Cramer at the address below:

Dr. Ken Cramer
Brown Recluse ID Project
Dept. of Biology
Monmouth College
Monmouth, IL  61462

You may also contact Dr. Cramer at

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