cobweb spiders

(Family Theridiidae)

cobweb spider (Family Theridiidae)
Photo by Alfredo Colon

Theridiidae is a large family of spiders known as cobweb spiders, cobweb weavers, comb-footed spiders, and tangle-web spiders. There are more than 3,000 species in 124 genera worldwide, about 230 species in more than 18 genera in North America north of Mexico, and at least 28 species in 18 genera in Minnesota. They are found almost anywhere, in fields on low plants, on tree trunks, in leaf litter, on fences, and in human houses. The family includes the poisonous black widow spider as well as the often feared but completely harmless common house spider.

Many cobweb weaver species build webs that are a haphazard arrangement of tangled threads, often with a sheet in the middle. This is the feature that gives the family two of its common names. However many other web types are constructed by other species in the family. Many species hang upside down in the center of their web. Others hide nearby with signal threads leading to their web.


Cobweb weavers are medium-sized spiders. Adults are to (3 to 15 mm) long. The upper side of the front part of the body (carapace) is flat and usually shiny with few hairs. The eyes and jaws are small. The abdomen is rounded and is usually globe-shaped, oval, or pointed.

Almost all species have a row of 6 to 10 slightly curved bristles (“comb”) on the last segment (tarsus) of each hind leg. This is the feature that gives the family one of its common names. They also have three claws at the end of each tarsus, but these are not visible to the naked eye.


Distribution Map



24, 29, 30, 82.

  Class Arachnida (arachnids)  


Araneae (spiders)  


Araneomorphae (typical spiders)  
  Infraorder Entelegynae (entelegyne spiders)  
  Superfamily Araneoidea (araneoid spiders)  

Subordinate Taxa


Achaearanea spp.

Argyrodes spp. (dewdrop spiders)

Ariamnes spp. (whip spiders)

Asagena spp.

Crustulina spp.

Dipoena spp.

Enoplognatha spp.

Episinus spp. (square-ended cobweb spiders)

Euryopis spp. (ant-eating spiders)

Hentziectypus spp.

Latrodectus spp. (widow spiders)

Neospintharus spp.

Nihonhimea spp. (comb-footed platform spiders)

Parasteatoda spp. (colorful comb-footed spiders)

Phoroncidia spp. (mushroom comb-footed spiders)

Platnickina spp.

Robertus spp.

Rugathodes spp.

Steatoda spp. (false widow spiders)

Theridion spp. (typical cobweb spiders)

Theridula spp.

Thwaitesia (mirror-ball spiders)

Thymoites spp.

Yunohamella spp.






Common Names


cobweb spiders

cobweb weavers

comb-footed spiders

tangle-web spiders













The hard, upper (dorsal), shell-like covering (exoskeleton) of the body or at least the thorax of many arthropods and of turtles and tortoises. On crustaceans, it covers the cephalothorax. On spiders, the top of the cephalothorax made from a series of fused sclerites.



On insects, the last two to five subdivisions of the leg, attached to the tibia; the foot. On spiders, the last segment of the leg. Plural: tarsi.


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Alfredo Colon


Cobweb Weaver with Prey

    cobweb spider (Family Theridiidae)      








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  Alfredo Colon

Location: Woodbury, MN

Cobweb Weaver with Prey

cobweb spider (Family Theridiidae)  






Created: 4/21/2019

Last Updated:

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