Callirhytis serricornis

Callirhytis serricornis, formerly Andricus serricornis, the kernel flower gall wasp, is a species of hymenopteran that produces galls on oak trees in California in North America. The wasp oviposits on coast live oak and interior live oak and induces a gall shaped roughly like a bottle or vase. The gall is brown in the first generation, and red and green in the second.