Wingspan c.20mm. This species is named after the group of three diffused dark spots arranged in a triangle; two along the leading edge of the forewing and the larger costal spot below. Other species with similar patterns usually show a white tornal spot, missing in the present species.

Areas where the larval foodplants are present.

The adults fly in June and July.

The larvae feed on the flowers and developing seeds of Wild Angelica and occasionally Hogweed.

It is a fairly local but widespread species, occurring sparsely over England, Wales and parts of Scotland. In a recent survey to determine the status of all macro moths in Britain this species was classified as local.

Scarce in Leicestershire and Rutland, with few confirmed records since the mid 2000s.