Edith's checkerspot caterpillar ~ 04/16/09 ~ Pinnacles

Edith's checkerspot caterpillar feeding on Indian warrior
Euphydryas editha feeding on Pedicularis densiflora
Orobanchaceae (formerly Scrophulariaceae)

Edited 05/24/14 - I originally posted this as variable checkerspot caterpillar (Euphydryas chalcedona).  When we went back 3 weeks later (from the westside on May 8, 2009, not the eastside as shown here), adult variable checkerspots were everywhere on flowers and mud puddles!  

Then, last year I went out with our local Monterey butterfly guy Chris Tenney, and he recalled Paul Johnson had told him Edith's feeds on Indian warrior, whereas variable is actually variable in its host preferences.  I have since confirmed directly with Paul that he has observed this host difference between these two look-alike local checkerspots. He's quite good at distinguishing adult Edith's from variable on the wing.  I changed the ID above from variable to Edith's.  Plus, I've seen first-hand both spp. flying together, so that May 2009 visit may very well have both on the wing.  Thanks, Paul!