The most rare U.S. species of bumblebee, last seen in 1956, has turned up once again in the White Mountains of south-central New Mexico. Called “Cockerell’s Bumblebee,” this prized pollinator is known from an area of less than 300 square miles, giving it the most limited range of any bumblebee species in the world. “Most bumblebees in the U.S. are known from dozens to thousands of specimens, but…