This source should be used with caution. It contains several errors.

The three Trichopoda species at the UC Berkeley museum are pennipes, lanipes, and plumipes. T. lanipes is very large and dark (not what I photographed). The other two species have lots of variation and it seems my fly could be either one of them, but I don't know enough about these flies to know what the defining characters are to bring them to species ID. T. subdivisa is not in the collection, but that doesn't mean it doesn't occur in California.

It doesn't have the orange abdomen of T. pennipes nor the black one with pairs of rectangular yellow spots of plumipes, that is why I was hoping for something else. I guess that we still need the help of somebody that really knows this.

some of the T. plumipes specimens at the museum had exactly the same abdominal pattern as the fly in my photos. I neglected to record who determined the species for those specimens, or when. It's possible the identification is not correct.

I noticed in a couple of Gary Steck's comments he refers to T. plumipes as an eastern US species. All of the specimens labeled T. plumipes in the Essig collection are from California.

Maybe we'll solve the mystery some day.

I felt lucky to find one of these, and especially lucky to have it hold still through numerous photos.