Wingspan 22 to 24 mm.This is the largest of the British Trachycera species, and rather dark, being mostly reddish-purple with two indistinct pale cross-lines and a whitish suffusion near the leading edge of the forewing.

In areas containing Blackthorn.

July and August.

Blackthorn is the preferred foodplant, the larvae constructing an untidy silken gallery amongst the leaves.

It is a local species occurring in the southern English counties. In the Butterfly Conservation's Microlepidoptera Report 2011 this species was classified as local.

It appears to be uncommon in Leicestershire and Rutland, where there are few records. L&R Moth Group status = D (rare or rarely recorded).