comb-footed spider

Taxonomy

See also list of spiders.

Comb-footed spiderA female comb-footed spider (Achaearanea pallens) with two egg sacs in its web.

comb-footed spider, (family Theridiidae), any of more than 2,500 species and around 130 genera of spiders distributed around the world. The webs of comb-footed spiders consist of an irregular network of threads from which the spider often hangs. The common name of the group is derived from a row of bristles on the tarsus, or “foot,” of the hind legs, which are used to throw silken strands over prey to ensnare it.

Red widow spider (Latrodectus bishopi) with red-orange body and black abdomen marked by yellow rings and red spots, on green leaves in Ocala National Forest.
Red widow spiderA venomous red widow spider (Latrodectus bishopi) in Ocala National Forest, Florida.

Major genera are Theridion, which includes the Hawaiian happy face spider (T. grallator); Parasteatoda, which includes the common American house spider (P. tepidariorum); Achaearanea; and Latrodectus, the black widows.

One Propostira species, discovered in 2026 and yet to receive its species epithet, uses a specialized “ballista” to launch Asian weaver ants (O. smaragdina) into its snare. The spider constructs a cone-shaped trap of tightly bundled silk lines attached to an anchor point, and applies a pheromone. When an ant bites through the silken cone, the stored tension launches the ant more than 30 cm (12 inches) into the spider’s web at remarkable speed, where it is ensnared and eaten.

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The Editors of Encyclopaedia BritannicaThis article was most recently revised and updated by Melissa Petruzzello.
Citation Information
Article Title: comb-footed spider
Website Name: Encyclopaedia Britannica
Publisher: Encyclopaedia Britannica, Inc.
Date Published: 24 June 2026
Access Date: November 14, 2026