San Diego Natural History Museum--Your Nature ConnectionSDNHM Field Guide
Adult female Agelenopsis aperta, copyright Jim Berrian
Adult female (note regenerated leg)

Agelenopsis aperta
Grass Spider



Both the female and male Grass Spiders measure 10-19mm in length, and have similar color patterns. The carapace has a central light medial stripe that is bordered by a pair of dark stripes. The abdomen is gray on the sides with a darker median stripe; this stripe is bordered by thin white stripes that may be broken posteriorly. Spinnerets are long, and the terminal segment is much longer than basal segment.

Range and Habitat

Grass Spiders occur from Texas to California and Baja California. In San Diego County it occurs in many habitats west of the mountains. It is common in overgrown open areas, gardens, and woodlands.

Natural History

This is our largest agelenid, producing large funnel webs with outer sheet as wide as half a meter.

Related and Similar Species

There are species with similar color pattern but the size and spinneret morphology are distinctive.


Chamberlin, R.V., and W. Ivie. 1941. North American Agelenidae of the genera Agelenopsis, Calilena, Ritalena and Tortolena. Ann. Ent. Soc. Am. 34(2):585-628.

Kaston, B.J. 1978. How to know the spiders, 3rd Ed., 272pp

Text by Jim Berrian. Photo © Jim Berrian.

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