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A medium size moth (approx. 3.5-4.0 cm wingspan). There are two forms, one a light grey with a purple or pink tint, the other dark purple-grey. Markings consist of doubled dentate antemedian and postmedian lines, often faint or difficult to trace except for a black spot or bar where they meet the costa. The large round orbicular and the reniform spot are filled with slightly paler scales. The area in the cell basad to the orbicular and the lower part between the orbicular and reniform is black. The rest of the area between the reniform and orbicular is partially filled with reddish brown scales and the area beyond the postmedian line is also mixed with reddish-brown, although these may not be obvious. Pale forms are quite powdery and contrasting, while dark specimens appear quite even and smooth. Sexes similar, but males with bipectinate antennae, females with simple antennae.

Adults are nocturnal and come to light. There is a single brood, with adults in Alberta from late July through August. The larvae is described and illustrated in color in Duncan (2006) They overwinter as partly grown larvae. They are solitary defoliators of a variety of conifers, in particular Englemann, Black and White spruces Douglas-fir, Balsam fir, Jackpine and Lodgepole pine.

Across the forested parts of southern Canada, from NS west to central BC; south to NC and WI in the east, and the Canada-USA border in the west; also in the Cypress Hills. Widespread in the boreal forest, foothills and mountains of Alberta. They are found in coniferous woodlands.

Although this is a widespread and apparently not uncommon species in the boreal forest, foothills and mountains of Alberta based on the FIDS larval collections (Prentice 1962) adults have rarely been collected. Open dots on the map are unconfirmed records, mainly FIDS larval collections as reported by Prentice. Lafontaine treats the adult color forms, which appear to be associated with different host plant species, as "host races". The pale form female illustrated above is from the Moths of Canada website.