William Cooper has studied the butterflies of Iguazú Falls, Argentina, for several years. In this lecture he will share his photos and recount his experiences visiting the falls. He will also discuss what he has learned since joining the Entomological Society of Washington and exploring the Smithsonian’s butterfly collection to help identify additional species. Cooper is a former professor of civil and environmental engineering at the University of California, Irvine, and program director of environmental engineering at the National Science Foundation.