Callirhytis carmelensis (Hymenoptera: Cynipidae)   (Synonym: Andricus carmelensis)
Mottled Acorn Gall Wasp
Oakland hills, Alameda County, California
July 24, 2016

The wasp gall is protruding on the left side of the acorn cap. The tip of the severely stunted acorn ovary is to the right of the gall. Host tree is Quercus agrifolia.