We have numerous Quercus agrifolia growing naturally on our property. We also have a few small oaks of other species which I started from acorns, so they are only a few years old and relatively small (under 2m tall): 1 Q. wislizenii, 1 Q. lobata, and 5 Q. kelloggii. I assume that my one small Q. lobata is not likely to attract Andricus quercuscalifornicus when there are no other Q. lobata within many miles. My guess at the ID of this guy is based solely on the ID of this photo . I did retain the specimen, with the intention of sending it to CAS along with several other insects which I have photographed and retained; the object being to link the photos at CalPhotos with specimens at CAS, as I have already done for several of the marine inverts (mostly nudibranchs) which I have already sent to CAS. Since I've not yet sent any insects to CAS, I don't know how likely a solid ID is once CAS has the specimens. I send specimens to CAS because I have a good friend at CASIZ who studies nudibranchs, and another friend who occasionally passes through SF and can drop the specimens off at CAS. I don't know if there is anyone near me (most likely at UCSC) who occasionally visits Essig and would be willing to drop specimens off there, assuming Essig would be interested in obtaining and IDing the specimens, and providing me with accession numbers to link specimens to photos at CalPhotos.
I also do still have a couple of specimens of Epinotia kasloana which Jerry Powell IDed on 10/28/2008 from photos I sent to MPG, and Jerry expressed interest in obtaining specimens. I could also retain specimens of other moth species for Essig/Jerry, as I am putting the black light/MV trap out almost every night to collect moths for BOLD, and many more moths show up than what I collect for BOLD.

I measured the 5 Essig Callirhytis apicalis specimens (not mine), and all except one were about 5mm, the other was 6mm. This would be my first guess for your above wasp given the time of year and the oak species you have around you. (I'll edit the A. quercuscalifornicus page so it no longer says that species is the largest in CA.)

You should look at the base of your Q. agrifolia trees, where the trunks meet the soil, and see if you can find any Callirhytis apicalis galls.

Sadly, most of the adult cynipids at Essig that did not come in with associated galls have been languishing in the collection for decades without any identifications. So I don't think yours would do much better there, and right now there is no collection manager so I would say it's not worth sending the specimen there at this point.

Moth specimens are a different matter since Essig has Jerry. If you want to know where to send the specimens I can ask someone (if you don't get the info from Jerry). May still be better to wait until there is a collection manager.

It seems to be very hard to find anyone to identify cynipids. Peter Bryant has sent specimens to BOLD (see here). BOLD does not have all CA cynipids in their database so it's not straight forward getting IDs there either, as far as I can tell.

In addition, there are quite a few undescribed cynipids in California. So I stay away from trying to identify adults unless I know what gall they came out of and what tree the gall was on -- and even then I've found quite a few galls that I know were created by undescribed cynipids.

I'm doubtful that your wasp here is Andricus quercuscalifornicus. It's too small, I would not expect it to be around in February (but other cynipids are!), and it doesn't sound as if you have a white oak population near you. But with 80+ cynipid species in California I don't know which other one it would be.

I hadn't noticed how many records you entered with CAS numbers into CalPhotos -- that's great! I may be able to set up an automatic link to the records on the CAS web site.