Female of Crossidius coralinus ssp. ferruginosus Chemsak & Linsley, 1959. C.coralinus is split up in several (more or less clearly defined) subspecies occurring in the western part of the USA. "California" is not especially precise, 4 of these forms are present here in quite restricted areas. But seeing the general body shape, punctures of the pronotum + elytra, it must be ferruginosus.