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For Insects, Spiders & Their Kin
For the United States & Canada
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Upcoming Events

Discussion of 2018 gathering

Photos of insects and people from the 2015 gathering in Wisconsin, July 10-12

Photos of insects and people from the 2014 gathering in Virginia, June 4-7.

Photos of insects and people from the 2013 gathering in Arizona, July 25-28

Photos of insects and people from the 2012 gathering in Alabama

Photos of insects and people from the 2011 gathering in Iowa

Photos from the 2010 Workshop in Grinnell, Iowa

Photos from the 2009 gathering in Washington


Family Philodromidae - Running Crab Spiders

spider - Thanatus - male running crab spider on Ceanothus - Tibellus oblongus Spider - Philodromus rufus Small spider on eucalyptus - Philodromus Which crab spider is this? Philodromus - Philodromus marxi - female Thanatus formicinus - female crab spider
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Chelicerata (Chelicerates)
Class Arachnida (Arachnids)
Order Araneae (Spiders)
Infraorder Araneomorphae (True Spiders)
No Taxon (Entelegynes )
Family Philodromidae (Running Crab Spiders)
Explanation of Names
From Greek philodromos (φιλοδρομος)- "lover of the race/course"
96 species in 5 genera in our region (1). The majority of the species are in the large genus Philodromus.
Philodromids tend to have the second pair of legs significantly longer than the first pair, which distinguishes them from the similar Thomisid crab spiders. In addition, thomisids have third and fourth legs that are shorter and more slender than the first two pairs of legs, while philodromid legs are subequal in length.
Internet References
~ PDF - Schick, R. X., 1965. The crab spiders of California (Araneae, Thomisidae). Range maps, keys, descriptions, & drawings of palps/epigynes.

Works Cited
1.Spiders of North America: An Identification Manual
D. Ubick, P. Paquin, P.E. Cushing and V. Roth (eds). 2005. American Arachnological Society.