His picture looked somewhat similar to the Great Spangled Fritillary, Speyeria cybele, but that is an eastern species. With my half-vast knowledge of lepidoptera (and a high-speed internet connection) I identified this western species as what I think is a Mormon Fritillary, Speyeria mormonia.
|Great Spangled Fritillary|
|Mormon Fritillary - BoMoNA|
It isn't usually this easy, but it does serve to illustrate that there are a lot of tools available to us amateur naturalists, even of those of us who lack Joe's gift for photography.