Wingspan 9.5-13 mm.
This moth emerges in a single generation, flying in July and August, sometimes coming to light. The females lay their eggs on the flowers of yarrow or sneezewort.
Early instars of the larvae are spent within the seedhead. Each forms a silken case, initially white, but brown when fully formed and about 5-6mm long. Pupation takes place within the case.
The moth is widespread in Southern England and Wales, and is also found in Central Scotland.