Wingspan c.10 mm.
A rare species in Britain, occurring coastally on sand-dunes, and known until recently from only a few localities on the south coast, although it has now been found on two occasions in Carmarthenshire.
The adult moth resembles Caryocolum blandella but is generally smaller, and doesn't have a row of dark spots close to the wing apex like that species. However, genitalia examination is recommended to be certain.
Flight time is July and August, and the adults are attracted to light.
Little is known of the early stages, but the species is known to feed on mouse-ear (Cerastium), especially little mouse-ear (C. semidecandrum).