Cynips quercusechinus

Cynips quercusechinus, the urchin gall wasp, is a species of gall wasp in the family Cynipidae. It induces galls in the leaves and leaf buds of blue oak and scrub oak. Like other oak gall wasps, it has two generations: a bisexual generation, and a parthenogenic female generation. In spring, the hatching bisexual generation produces hollow green galls in leaf buds. In summer, the unisexual generation induces its galls, which are red or pink and resemble sea urchins, on the undersides of leaves. These galls are about 10 mm in diameter. The galls fall with the leaves in autumn, and the larvae inside of them emerge as adults in the spring and lay their eggs.

This species was first described by Carl Robert Osten-Sacken in 1870 based on specimens from California.