Wingspan 18 to 22 mm. This is a distinctive species. It is very variable, and many different forms have been described, but they often have a combination of pale or whitish green ground colour with blackish markings.

An inhabitant of Oak woodland.

The moth is on the wing in August and September, and again in April and May, having overwintered as an adult.

Locally distributed, mainly in the southern half of Britain. In the Butterfly Conservation’s Microlepidoptera Report 2011 this species was classified as local.

Occasional in Leicestershire and Rutland.