Found on a rocky path near a cedar glade. Saw a few times puddling on some sort of animal dung. I looked up several resources. One:
http://www.naba.org/chapters/nabanj/butterflies/southern_cloudywing.html
Was helpful in particular. The white line curving over the line is interrupted in what I found as it is with Northern Cloudywing. Though hard to see, I couldn't see a a pale patch at bend of antennal tip that is found in Southern. The forewing spots on this butterfly seem smaller than the spots I have seen on photographs of Southern.