The mysterious case of the Appalachian Rusty-patched Bumble Bee (Bombus affinis) holdouts. There are no more RPBB's in most of North American, people have looked, it's not really a question of overlooking them any longer, they are just all gone. Fingers point to a set of introduced European bumble bee pathogens. And, ignoring the more famous residual population in the WI/MN/IA/IL area they still persist in the highland area between WV and VA. As proof. Here is a picture of a Bombus affinis inadvertently collected by Mark Hepner recently in West Virginia.