Callirhytis carmelensis (Hymenoptera: Cynipidae)
Mottled Acorn Gall Wasp
Del Valle Regional Park, Livermore, Alameda County, California
April 24, 2021

Acorn gall (with wasp larva inside) on host Quercus agrifolia (coast live oak). The ant is eating honeydew secreted by the gall.