Wingspan c. 10mm
Until the early 1990s, this species had been overlooked in the British Isles. In that year, specimens from Herefordshire previously thought to be Mompha divisella were correctly identified and subsequent investigations revealed other overlooked records.
It is now found regularly in the south Midlands and southern central England, although dissection is usually required to be sure of identification.
The larvae feed on great willowherb (Epilobium hirstutum), creating one or more galls on the stem or a shoot.
Adults emerge between July and September, after which they hibernate for the winter, appearing again in the spring.