A female Dasymutilla occidentalis, identified via http://bugguide.net/node/view/816460
Located in the Wellbarn trail above the San Joaquin River
The genus Dasymutilla belongs to the Mutillidae family. The females of the genus are well known for their painful sting, which is where many gain their common name, Cow Killer. The female is wingless and often resemble large ants while the males still retain their wings. The larva of the Dasymutilla are external parasites to various types of hymenoptera. When disturbed the Dasymutilla makes a high-pitched squeaking sound identical to the Pogonomyrmex (Harvester ant).