Butterfly in winter

A butterfly from the Popp Butterfly Conservatory in Oneonta, NY. There are feeders all over the place, and the butterflies drift over, have a rest and a feast. It's better than the jungle because there aren't any insect-eating animals here!

I have no idea what species this is and I didn't think to ask the friendly people there before I left. I can only assume they are a tropical insect because I've never seen anything like it in the outdoors here!