Trichoteras frondeum (Hymenoptera: Cynipidae)   (Synonym: Andricus frondeum)
Corduroy Hills Trail, Las Trampas Regional Park, Contra Costa County, California
May 24, 2009

Wasp gall in dead bud scales on Quercus chrysolepis (canyon live oak). This is a monothalamous gall (has only one larval chamber, with one larva). The gall has been cut open to show the larva.