WASHINGTON, May 28 (UPI) -- Entomologists say a newly identified butterfly in Texas may be the last truly distinctive butterfly species left to be discovered in the United States.
Although specimens of Vicroy's Ministreak were deposited in the Smithsonian entomology collections a century ago, this species was unrecognized because it was confused with a common, similar-looking butterfly, the Gray Ministreak, they said.
Writing in the journal ZooKeys, Jeffrey Glassberg, president of the North American Butterfly Association, and Bob Robbins, the butterfly curator at the Smithsonian, say the new species can be differentiated from the more common Gary Ministreak by eye color -- Vicroy has distinctive olive-green eyes while the Gray has dark brown or black eyes.
The two species differ slightly in wing patterns and have different but overlapping geographic distributions and habitat requirements.
Whether Vicroy's Ministreak turns out to be the last truly distinctive butterfly to be discovered in the United States, the era of new U.S. butterfly species is ending, they said. The search for new butterfly species must move to tropical Central and South America, where hundreds of species await discovery.