Wingspan 26 to 34 mm. The males of this species have distinctively long and narrow forewings, the females being more normally proportioned.

Can be confused with the much more common Mother of Pearl.

Records must be supported by detailed photographs.

The moth inhabits woodland and marshy fenland.

Flies at night in June and July.

The larvae feed mainly on hemp agrimony (Eupatorium), but also other plants.

It occurs in the southern half of England and in Wales. In the Butterfly Conservation's Microlepidoptera Report 2011 this species was classified as common.

Uncommon in Leicestershire and Rutland which is nearing the northern edge of its range.