Another common lady butterfly but is a little more restricted in its range being found west of the Rocky Mountains.  It flies from spring to fall with multiple broods and has the same habits as the other ladies, the Painted Lady, (Vanessa cardui) and the American Lady, (Vanessa virginiensis).  For a more detailed description on how to tell the ladies apart, I refer you to the excellent Kaufman Field Guide to Butterflies of North America.