The moth can be found across the Palearctic realm (northern and central Europe, Russia, eastern Siberia, Russian Far East, Amur).

The imago can be easily confused with Pheosia tremula but P. gnoma is usually smaller, and the ground colour has usually less brown in it.

The chief character by which it may be distinguished is the broader and clearer white wedge-shaped mark between veins 1 and 2 on the forewings of P. gnoma.

— Throughout Central Europe, northward to Lapland, southward to Southern France, Northern Italy, Croatia, and the Bukovina; East Asia (Amurland).

Larva dark brown-red or bright light green, glossy, with blackish transverse bar on the tubercle and broad orange-yellow lateral line, at the upper edge of which the white-edged black stigmata are placed; on the underside a similar yellow longitudinal stripe.