|MadSci Network: Zoology|
To be sure I would need to see the specimen, but I can offer the following observations that might help. First, I doubt that these are black widows because, although I have found one individual without markings in the past, I have never seen populations without some sort of red mark on the underside. Even brown widows (Latrodectus geometricus) have an orange hour-glass mark and red widows (Latrodectus bishopi) have a red bar on the underside. My guess would be a comb-footed spider (Theridiidae- same family as the black widow) in some other genus, such as Steatoda. Although one European species of Steatoda has been implicated in spider bite cases, none of the North American species has been to my knowledge. There are other theridiid spiders that it might be, but I obviously cannot be sure unless I see the specimen Ref: Kaston, B. J. 1978. How to know the spiders. 3rd ed. Wm. Brown, Dubuque, Iowa. Levi, H. W., and L. R. Levi. 1968. Spiders and their kin. Golden Press, NY.
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