of your photo, and can't find any distinguishing characteristics for P. indra that fit. However, it is indeed a good match for a dark form caterpillar of P. polyxenes coloro.

Moved from Papilio.

Moved from Butterflies and Moths.

Perhaps more likely to be a desert species such as P. polyxenes coloro. Black form larvae are pretty common in that species. I didn't directly compare the photo with P. indra larvae, but they can look rather similar to this as well. If the leaf behind is of the food plant, I'd tend to lean toward the later. Maybe somebody will look in who knows these larvae much better.

This looks like an Anise Swallowtail, Papilio zelicaon, but this particular one looks faded.

I don't know what species you have there, but maybe one of our west coast contributors will comment.