Identifying features
Wingspan 40–56 mm. Both wing pairs are white above, often with a yellow tinge in the female. The forewing tip has a narrow grey patch along the margin; males occur with or without a black dot, while the female has two dots. The hindwing underside is yellow with grey dusting in the first generation and almost pure yellow in later generations.
Similar species
Resembles cabbage butterfly, but is significantly smaller; the dark area on the forewing apex is typically limited to the anterior third of the wing margin. It also resembles green-veined white, but can be distinguished by the fact that the underside of the hindwing does not exhibit prominent grey markings.
Distribution
Appearing irregularly, but fairly common in most years south of Dovre. Rarely further north, but found as far north as Kirkenes.
Biology
The eggs are laid on leaves of cabbage, turnips, and other plants in the cabbage family. The larva is green with a yellow dorsal and lateral line and measures approximately 25 mm. The pupa hangs on brick walls, fence posts, and similar structures.