\Or*gy"i*a\, n. [NL., fr. Gr. ? the length of the
outstretched arms. So named because, when at rest, it
stretches forward its fore legs like arms.] (Zo["o]l.).
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}.