Wingspan 5-6 mm.
A single-generation species with adults flying in June, and the larvae feeding in September and October. It is common throughout much of the British Isles.
The larvae mine the leaves of hawthorn (Crataegus), apple (Malus) and one or two others. The mine is initially narrow with linear frass, but becomes wide with reddish frass in neat arcs. The larva is bright green.
The adults have plain dark forewings with a hint of purple, and an orange head.