Wingspan 13-16 mm.
A scarce species, distributed mainly in the south and south-east of England, also ranging northwards into south Yorkshire and Lancashire.
Flying in July, the adults have bronzy forewings with a central purplish fascia, and the males have long silvery-white antennae, black at the base. The females have shorter, blackish antennae with white at the tips.
The larval foodplant is black horehound (Ballota nigra), the larva feeding at first on the seeds and then later in a case made from fragments of the foodplant.