Spiders

I've seen an odd looking spider at my house in New York, and would like to know more about it.

The Oracle frequently receives requests to identify spiders and other invertebrates. These requests come from all over the United States and other countries. Often the person wants to know if the spider is poisonous. The Oracle is unable to provide this kind of information.

The best way to determine what kind of spider you have found is to locate an extension service or an expert at a university or college near you. These people will be most familiar with the species that are found in your area.

Another way to identify your critter is to use the Internet. There are many fine WEB sites devoted to describing the spiders of different areas of the United States and other countries. Using a search engine such as Google (http://www.google.com) type in the key word to describe your organism. Often a phrase combining the name of the organism and the state or country where you found it can produce some very good hits. For example, the key word phrase, "California spiders", produced a number of Web sites with information and pictures of spiders found in that state. You could also check your local library for field guides for the spiders in your geographic area.

When trying to identify a spider there are certain characteristics that are important things to note. The most reliable way to distinguish major spider groups is by the arrangement of the eyes on the "head" region of the spider. On the large spiders, the eye arrangement is easily visible. A hand lens or magnifier may be necessary for smaller spiders. The following key can help you place your spider in one of the major groups.

1. Eyes in 3 rows, arranged in a 4, 2, 2 pattern (Wolf spider & Jumping spider)
2. Eyes in 2 rows of 4 (most spiders)
3. Eyes in 3 pairs (Brown recluse and relatives)

Other characteristics to take note of are:

• Movement- does it jump, move sideways, run forward?
• Is it in a web or ranging free?
• If it has a web is it orb shaped, funnel shaped, a sheet or an irregular cobweb?
• What is the spider's size, shape and color?
• What habitat was it found in?
• Answering these questions will help you make a more precise identification.

Here are a few excellent spider/invertebrate WEB sites:

• Interesting facts About Ants
• Common Spiders Found Around Homes and Buildings
• Common Florida Spiders
• Southern Idaho Insect Guide
• The Bug Club Bug ID
• The Alaska Science Forum Bugs Index
• Colorado Spider Survey
• Spiders of Home and Landscape, University of California

Not everything is on the web. Some resources in print might also be interesting:

• Audubon Society Field Guide to North American Butterflies by Robert Michael Pyle (Knopf, 1981)
• Audubon Society Field Guide to North American Insects and Spiders by L. and M. Milne (Knopf, 1980)
• Butterflies and Moths, A Golden Guide by R.T. Mitchell and H.S. Zim (Golden Press, 1964)
• A Field Guide to the Insects of America North of Mexico by D.J. Borror and R.W. White (Peterson Field Guide Series, Houghton Mifflin, 1970)
• Insect Pests, A Golden Guide by G.S. Fichter (Golden Press, 1966)
• Insects, A Golden Guide by H.S. Zim and C. Cottern (Golden Press, 1951)
• Peterson's Field Guides-Series 8 (to Butterflies, Beetles, Moths, etc.) by R.T. Peterson
• Scorpions and Venomous Insects of the Southwest by Erik D. Stoops and Jeffrey L. Martin (Golden West Publishers, 1995)

Last updated 10 February 2003