CEDAR RAPIDS, Iowa (AP) -- A butterfly that was once a common sight in Iowa is a candidate for protection on the endangered species list, but some experts say it may already be too late.

According to The Gazette in Cedar Rapids, the Poweshiek skipper was added to the list this year after its apparent disappearance from Iowa and neighboring states.

Dennis Schlict is a retired high school teacher in Cedar Rapids and author of "The Butterflies of Iowa." He says the U.S. Fish and Wildlife Service waited too long to list the tiny butterfly. He says the butterfly has been disappearing over the past decade.

Expert Frank Olsen surveyed 26 locations for the butterfly in 2007 but only found the butterfly at one of the sites.