Northern Prairie Wildlife Research Center
Females are wingless. The male wingspan is 3.3 cm. Forewing is gray to black with a small subanal spot; hindwing is dark red-brown. This lymantriid is known as the Douglas-fir tussock moth and is considered a forest pest causing severe defoliation of certain conifer species and is widely distributed in western North America. Moths fly in midsummer to fall. Caterpillars feed on the foliage of species of Pinaceae, in particular Douglas-fir (Pseudotsuga menziesii) and true fir (Abies).
Similar species: Orgyia vetusta occurs in the Pacific West while Orgyia cana is widely distributed, both species have wingless females, males with a gray brown forewing and a dark brown hindwing, caterpillars feed on foliage of flowering trees and shrubs.