Wingspan c.24 mm.
A rare migrant species that has in the past become a transitory resident, although not since 1869. Nowadays it is just a very occasional visitor, usually to south or south-eastern coastal localities.
The species occurs in Europe, where it inhabits damp marshy habitats, and flies in two generations - June/July and August/September.
The larval foodplants abroad are mint (Mentha) and gypsywort (Lycopus).