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Species Steatoda borealis

Steatoda borealis - female Both a female and male of the same species of spider? - Steatoda borealis - female Steatoda's - Steatoda borealis - male false widows - Steatoda borealis - female Steatoda borealis - male Infested Spider - Steatoda borealis Spider  - Steatoda borealis weaver – Steatoda borealis? - Steatoda borealis
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Chelicerata (Chelicerates)
Class Arachnida (Arachnids)
Order Araneae (Spiders)
Infraorder Araneomorphae (True Spiders)
No Taxon (Entelegynae)
Family Theridiidae (Cobweb Spiders)
Genus Steatoda
Species borealis (Steatoda borealis)
Explanation of Names
Latin for "northern"
Females reaching a maximum size of about 7 mm
The abdomen is reddish brown with a lighter "T" shaped mark at the front end. The underside of the abdomen is also considerably lighter than the upper side.

Note that several other species in the genus can have nearly identical markings.
East of the Rocky Mountains in the United States to Alaska. Typically in northern states, but has recently been found in southern ones over the past 50 years or so.
Most likely to be found under bark and stones, in rock crevices, on bridges and in outbuildings and unfinished basements.
Life Cycle
Click on the image below to see the life cycle.
This species is native to North America.

Both males and females have a rough surface with ridges on the abdomen front that forms a stridulating organ. The spider can make sounds by rubbing this against the carapace. (1)
Works Cited
1.Common Spiders of North America
Richard A. Bradley . 2012. University of California Press .