Wingspan 22-33 mm. Sexually dimorphic, the males are slightly smaller and darker than the females. Both sexes have bright white hind wings.

In marshes, fens and other wet habitats.

The adults fly in July and August and are attracted to light.

The slender larva mines the leaves, stems and upper rootstock of Bulrush from September to May, pupating there in June and July.

Locally distributed in south and south-east England, with some records as far north as Cheshire and Lancashire. In the Butterfly Conservation’s Microlepidoptera Report 2011 this species was classified as local.

Occasional in Leicestershire and Rutland. L&R Moth Group status = C (very scarce resident or rare migrant)