Photographed in a montane coniferous forest opening, where by happenstance it chose to land on a net being held at rest during a conversation. That would seem a mal-adaptive behavior in terms of natural selection...but in this case the impact was neutral, as the holder of the net was interested in Timema, not butterflies :-)

Butterflies of many types were out, and I wished I had brought my copy of Shapiro(1)(2007). Fortunately, viewers of this post can read some of Art Shapiro's very interesting & informative ecological insights at this link. Much of that commentary was nicely borne out here, directly or indirectly. (For instance, that plants of the genus Ceanothus are larval hosts for this species...C. cordulatus was abundant and in glorious flower throughout the montane elevations here.) Below are images of eggs and the caterpillar...both on Ceanothus:

     

Upper wing pattern of other Sierran individuals appear below:

       

Another of nice reference (for diagnostic photos & taxomomic data) is here.