Wingspan c. 16-22mm.
This species is an occasional immigrant, mostly to the south-eastern counties, and has established localised colonies in that region.
The adults resemble a large Yponomeuta species, but have a row of black dots along the terminal edge of the forewing. Often there is a greyish area along the dorsum.
The larvae feed on the flowers and developing seeds of viper's bugloss (Echium vulgare).
Moths are on the wing between May and July.