Quercus douglasii
Acorn galls
Large cell filling inside of acorn whose cup is 6 mm in dia. Fig 190. The only specimen was empty in October (Stanford CA).
Fig 190. Unknown. A single large cell inside a small acorn of Q. douglasii in Oct. (Stanford). The adult had escaped. Diameter 5.0 mm.
”- LH Weld: (1957) Cynipid Galls of the Pacific Slope©
Reference: https://babel.hathitrust.org/cgi/pt?id=coo.31924018313555&view=1up&seq=89