Observation notes: The butterfly was going for nectar at a New Mexico Thistle, cirsium neomexicanum, along the roadside.
Verified by: stevecary
Verified date: May 13, 2021
Coordinator notes: I think you have the correct ID. I have difficulty distinguishing Viereck's from Deva and usually rely on a good dorsal shot. but Glassberg points to the HW fringe as gray in Viereck's and white on Deva. yours clearly has a gray fringe, so I agree with Viereck's.