Wingspan 17-21 mm.
Resembling a large and more brightly-coloured Plutella xylostella, this rather scarce species is found locally in scattered locations from northern England to the Highlands of Scotland and parts of Ireland.
The adults emerge in September and remain in this stage until around April, hiding in thick cover over the winter.
The life history is not well known, but in Britain the larva is believed to feed on dame's violet (Hesperis matronalis). The pupa, like other members of the genus, is formed in a network cocoon on a leaf.