Callirhytis congregata (Hymenoptera: Cynipidae)   (Synonym: Andricus congregata)
Sausage Flower Gall Wasp
Knowland Park, Oakland, Alameda County, California
December 8, 2012

Old catkin gall. Host is Quercus agrifolia (coast live oak). Part of the gall is missing, and 5-6 larval chambers are visible inside. Gall is polythalamous (multiple larvae). One exit hole is also visible.