San Diego Natural History Museum--Your Nature ConnectionSDNHM Field Guide
Cheiracanthium inclusum on a leaf. Photo copyright Jim Berrian
Adult female

Cheiracanthium inclusum
Agrarian Sac Spider

MITURGIDAE

Description

The female agrarian sac spider measures up to 0.25 inches (6.4 mm) and is slightly larger than the male, which measures up to 0.22 inches (5.6 mm). The coloration is the same in both sexes: the carapace is yellow-orange; the abdomen and legs are yellow; and the chelicerae are dark orange-brown. An indistinct heart-shaped mark can be found on the abdomen.

Range and Habitat

This species is very common and is widely distributed throughout the United States. It can be found on garden vegetation such as shrubs and citrus plants, under rocks and leaves, and in buildings

Cheiracanthium inclusum on a leaf. Photo copyright Jim Berrian
Adult female
Natural History

The agrarian sac spider overwinters as an immature individual and matures in May and June. It may build a cocoon-like sac of silk for shelter during the day. At night it hunts for small insects and possibly other spiders.

This spider may inflict a painful bite if threatened. However, its bite isn't considered as serious as that of the brown recluse.

Related and Similar Species

Cheiracanthium mildei is similar but most often found around houses. To distinguish between these two species, the genitalia must be observed with a microscope.

References

Dondale, C.D. and J.H. Redner. 1982. The sac spiders of Canada and Alaska, (Araneae: Clubionidae and Anyphaenidae). In: The Insects and Arachnids of Canada, Part 9. Can. Dept. Agr. Publ. 1724, 194pp.

Text by Jim Berrian. Photos © Jim Berrian.

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