This is a small to medium (wingspan 33–39 mm) species with cryptically coloured forewings, varying from light to dark brown, sometimes with a reddish tinge.

Forewing grey, dark speckled:costa black-spotted: claviform stigma small: orbicular round, pale, sometimes whitish: reniform large, the lower lobe dark grey, all three finely black-edged; veins towards termen finely black; hindwing dull whitish, with abroad border and the veins fuscous.

the forewing is more variegated, light and dark, the larger pale orbicular stigma and a pale patch obliquely below it forming a prominent streak; — indistincta Tutt has a uniform dull appearance, without speckling; — albifusa Walk.

[now subspecies A. t. albifusa (Walker, 1857) Nova Scotia], described originally from a N. American specimen, but probably a rare general aberration, has occurred at Portland, on the chalky South coast of England: it is grey with a yellowish gloss, with a pale band as in farkasii, joined by a second pale oblique band from apex.

- Larva varying from green to brown, thickly dark-dotted; dorsal line fine, pale, subdorsal lines broader, all black-edged; spiracular stripe broad, yellow varied with reddish.