Identifying features
Wingspan 44–54 mm. The male is yellow or pale yellow, with a broad, brown-grey outer edge band on the forewing and the front part of the hindwing. The female is greenish-white, with a corresponding edge band. Both sexes have an oval disc spot on the forewing, a yellow or white central spot on the hindwing, and a narrow, red fringe on both wing pairs.
Similar species
Can be confused with pale Arctic clouded yellow and pale clouded yellow, but differs in having a single marginal band. The male can resemble the yellow form of Hecla sulphur, which is considerably smaller.
Distribution
Quite common in the interior parts of Øst- og Southern Norway, and locally common in Northern Norway. Seems to be lacking in coastal areas of Southern Norway and in the outer areas of Vestlandet. In Trøndelag, the species has declined in recent years. In the mountains of Southern Norway, some specimens have been found up to 1200 m.
Biology
The eggs are laid on the leaves of bog bilberry. The larva is green with small black spots and a yellow lateral line, and it lives on bog bilberry and bilberry; it grows to approximately 35 mm. Overwintering occurs in the larval stage, and pupation takes place in the spring.