This link to the Biovision.com page shows eggs and immature forms of B. hilaris. I think yours is a pretty close match to the late instar nymph they show -- we'll see what others think. Also, although the picture is a bit blurry there's another image of some nymphs on this interesting blog post from one of our local bug-watchers in Tustin. Hope that helps!

I returned to the spot where I found these today, and I managed to find a couple of adults and get a few shots in before they scurried off; and though these images aren't exactly good enough for the guide in my opinion, I think its safe to say that this is definately B. hilaris. All the nymph pictures on the internet also seem to match.

I really wasn't expecting to get a species level ID from just a nymph shot, I am quite impressed!

... I definitely would not have recognized this nymph shot as B. hilaris on my own and did not put two-and-two together from your description of the adult. I just followed up on his very astute suggestion. Glad you managed to put all the pieces of the puzzle together -- that can be so satisfying!

I'd call this a team effort. Also, Hartmut deserves credit for getting these critters IDed in the first place.

Yay team!