Heteroecus malus (Hymenoptera: Cynipidae)
Mt Hamilton Road, Santa Clara County, California
September 25, 2011

The wasp that created these galls was described by Kinsey in 1922. In 1896, Ashmead described another wasp, Heteroecus chrysolepidis, that creates similar galls on the same host. Kinsey thought these might be the same species but without detailed studies of the wasp specimens it's not clear. Specimens (wasps and galls from which they emerged) at the California Academy of Sciences are labeled Heteroecus malus. The galls created by this wasp tend to occur in grape-like clusters and have a fine white pubescence when fresh. Underneath the pubescence, the galls are green or green with red. Older galls are tan. The galls are monothalamous (single larva). Host is Quercus chrysolepis (canyon live oak).