What is "orgyia leucostigma"

Orgyia \Or*gy"i*a\, 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.] (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.

The white-marked tussock moth (Orgyia leucostigma) is a moth in the family Lymantriidae. The caterpillar is very common especially in late summer in eastern North America, extending as far west as Texas, Colorado, and Alberta. Also found in Southern England Europe.