Moved from Andricus laniger.
Current name is Andricus quercuslanigera, per Kathy Schick.

I had a lot of adults emerge from the galls from these oaks earlier this year ... just got around to posting a photo of one of them here:

Moved from Gall Wasps.

Following up on the discussion on this page, these galls are likely caused by the cynipid wasp Andricus laniger, based on Lewis Weld's Cynipid Galls of the Eastern United States (1959). Of the eight leaf galls listed on Quercus virginiana, Andricus laniger is the only one that is as woolly as these are and occurs on the underside midrib vein. The description in Felt's Plant Galls and Gall Makers (1940) agrees with Weld's.

I'm reluctant to move these to a species page yet because of my limited experience with east coast oaks and galls. However, a friend and I are trying to raise some of these larvae to adulthood, and that will help with the ID. Adult cynipids may not emerge until spring.

Meanwhile, I was wrong about these wasp larvae having no parasites here in California. I've had one parasitoid wasp emerge so far from the galls I brought home -- posted here.