Twin-spot Carpet

The wingspan is 24–29 mm. The ground colour of the forewings is generally pale or dark grey. There are two dark stains near the apex and the costa of the forewing. The wavy crosslines delimit a darker mid field and a darker marginal field. It is very variable in colour, with the male considerably darker than the female; in some districts the sexual dimorphism is quite striking. This sex is also appreciably smaller and narrower-winged than the male and has a much stouter abdomen. - ab. ochroleucata Auriv. is unicolorous grey yellow or yellow brown without markings except the light subterminal line. - In ab. nigrofasciata Rbl. The ground colour is darkened and the median band narrow, almost black. - ab. nigra Prout has uniform blackish brown wings. In hethlandica Rbl. the male is more or less bright orange brown, the female lighter ochreous brown or fawn colour.

The larva is long and slender and differs so from most species of the genus Perizoma. It is grey-green in colour with short, dark brushes.

It is found in northern and central Europe; further south and east it seems to be confined to the mountains Pyrenees, Alps, Urals.