orgyia, prop. n. [NL., fr. Gr. the length of the outstretched arms. So named because, when at rest, it stretches forward its fore legs like arms.].
A genus of bombycid moths whose caterpillars (esp. those of Orgyia leucostigma) are often very injurious to fruit trees and shade trees. The female is wingless. Called also vaporer moth. [1913 Webster]