Adult males are grayish brown moths with mottled light and dark markings.

Larvae (caterpillars) are 20–26 mm (0.79–1.02 in) and colorful with red spots, white spines, conspicuous red-tipped white tufts or "tussocks", and dense bunches of long, black hairs projecting to the front and behind.

[2][3][4][5] The Douglas-fir tussock moth is native to forests of western North America and outbreaks have been identified in British Columbia, Idaho, Washington, Oregon, Nevada, California, Arizona, and New Mexico.

[5][7] Eggs hatch in spring (May to June) and the young larvae begin feeding on new foliage (the current season’s growth of needles).

[8][9][10] Outbreaks subside on their own, but silvicultural techniques for managing affected timber can be employed,[4] or the chemical carbaryl can be sprayed aerially.