A worldwide community photographing and learning about wildlife
Bugguide says there are 10 species of Orgyia in North America (http://www.nearctica.com/nomina/lepid/le...). It lists Orgyia antiqua, cana, definita, detrita, falcata, leucostigma, leuschneri, magna, pseudotsugata, vetusta. Now, I've dealt with leucostigma before, and this one definitely isn't leucostigma. So you've got it narrowed to 9 species now. Good luck!