Explanation of Names
From Greek philodromos (φιλοδρομος)- "lover of the race/course"
Spiders of North America 2nd Edition states that there are 92 species in 6 genera in our region (1)
. A 2016 paper added another genus (Rhysodromus
The majority of the species are in the large genus Philodromus.
Not diagnostic, but some helpful features:(3)
Second pair of legs longer than first
All legs similar in size (Thomisids have back pair smaller than front pair)
Often with a stripe on the back of the head
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.
Often found on plants (stems & leaves).
These spiders are active predators.
Schick, R. X. (1965). The crab spiders of California (Araneida, Thomisidae). Bulletin of the AMNH; v. 129, article 1. (Full Text Here
Dondale, C. D., & Redner, J. H. (1978). The Crab Spiders of Canada and Alaska (Araneae: Philodromidae and Thomisidae)(The Insects and Arachnids of Canada, Part 5). Agriculture Canada Publication, 1663. (Full Text Here
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