Females of this group are generally longer than the males; females measure 13-15mm and males are 7-9mm. The female's body is dark brown to black, sometimes with darker marks on abdomen. There are eight small eyes are on a bump on the carapace. The cribellum is present but can be difficult to see. The calamistrum is short. Coloration of the male is similar; the palps are very long.
Range and Habitat
This group of spiders occurs across the United States in the southern states. In San Diego County, they can be found in desert and coastal habitats, building their non-sticky tanglefoot webs in brick and rock walls, wood fences, and on the ground.
Females may live seven years.
Related and Similar Species
Spiders in this group appear similar at first glance to small tarantulas. Tarantulas, however, have elongate spinnerets, a larger carapace, and forward-facing chelicerae. Black widows are shinier and have red marks on the underside of the abdomen.
Chamberlin, R.V. and W. Ivie. 1935. Miscellaneous new American spiders. Bull. Univ. Utah 26(4):1-79.