May to early July. An attractive species well distributed in England, Wales, Ireland and the Channel Islands.

The white wings have blackish clouding in the outer area of the forewing. The extent and intensity of the clouding varies, generally stronger in males, and is usually accompanied by two central forewing spots and an additional mark at the centre of the trailing edge.

The larvae can be seen from late June to late August before they overwinter as pupae on the ground among plant debris. The adults are often seen flying at dusk, especially along hedgerows.