Callirhytis apicalis (Hymenoptera: Cynipidae)   (Synonym: Andricus apicalis)
Knowland Park, Oakland, Alameda County, California
May 12, 2011

Fresh, red wasp gall at base of Quercus agrifolia (coast live oak). To the left of the gall is what is most likely a piece of an old gall, the central chamber with an exit hole.