Dogface Butterfly, one of the sulphurs. A view of the wing topsides makes the ID easier, they have a very bold pattern.

Thanks for the quick ID! Always known them (Sulphurs) only as "yellow" butterflies and am just starting to appreciate the number of subtle variations.

Surprised I didn't learn the Dogface Butterfly is the state insect of California while I lived there; an odd name a young kid would not likely have forgotten if someone had mentioned it.

This post was edited by bostedo on Mon, Nov 18, 13 at 14:54

The California Dogface butterfly is yet another subtle variation, and a different species, from yours.