I suspect you are correct about them both being Mylitta. I looked at Kaufman, and also Shapiro, Glasberg, Stewart and a couple of older guides. But I remain unconvinced about the upper insect, even though the specific habitat (weeds on the side of a canyon) and the geographic location (200 miles south of current known location) mitigate against P.orseis. Interestingly, the pictures in Shapiro's Field Guide to Butterflies of the San Francisco Bay (and likely the best guide for our local butterflies) ... look very different from the ones in Kaufman. In Kaufman's text, he says about Mylitta "There is much individual variation. This would be no problem if the California Crescent (P. orseis) did not exist!"

I'd agree with that statement! The upper one looked a whole lot like the California Crescent in my Kaufman, too.

In my message above, I said "In Kaufman's text..." Meant to say "In Shapiro's text..."