Hymenoptera: Cynipidae
Leaf Gall Wasp
Mt Diablo State Park, Contra Costa County, California
April 1, 2007

This gall appears in Ron Russo's Field Guide to Plant Galls of California and other Western States but has not yet been scientifically described. It's possible that the gall maker is the larva of a bisexual generation of a species whose unisexual generation has already been described. This gall is on Quercus lobata (valley oak).