Your ID is probably correct but what in this image eliminates a female Zerene cesonia?

Thanks for asking - since the range for both species overlaps in southern California, both species might be seen in this location. I think this is a female California Dogface because my guide books note a pink ray at the base of the hindwing in eurydice, and that the female eurydice is all yellow (no black border showing through from above). I see a strong pink ray at the base of the hindwing, but can't see black showing through from above on this individual, so I believe it's likely a female eurydice. Of course, I could be mistaken, since I've never seen either one in person. :)

I've lived in the adjacent Orange county for 40 years and seen neither. While getting pretty dusty, Orsak's 1977 The Butterflies of Orange County, California remains the most definitive text for this area. For Z. cesonia, it notes very few sightings - five in 38 years - and says the b'fly can be encountered as a stray anywhere in the county. Less than a page is devoted to this species. No information on habitat or larval foodplant is provided.

OTOH, Z. eurydice garners six pages. Most recorded sightings were in the Santa Ana Mountains at both high and low elevations. Others among the fifty listed sightings ranged throughout the county, including coastal areas. Purple flowers, roadside thistles in particular, were popular feeding spots.