The brown-and-yellow insect, which graced a stamp in 1996 to reflect its endangered status, has been hard to locate lately.

Sightings of the Schaus have fluctuated dramatically over the past 20 years, from the hundreds to the dozens. In recent years, habitat loss, drought, and pesticides have contributed to a precipitous drop in sightings, from 41 in 2011 to four in 2012.

Currently, the butterfly is believed to live only in a small patch of forest called tropical hardwood hammock, dense with evergreens and ferns, on Elliot Key in the Florida Keys. The U.S. Fish and Wildlife Service listed the Schaus as endangered in 1984.

Now the butterfly's odds of survival are improving, thanks to researchers from the University of Florida, the National