Wingspan 11 to 15 mm.

Please provide a photograph and retain specimen determination by genitalia examination (gen. det.) may be required.

Fens, marshes and on river-banks, especially in areas where Common Reed is present.

There is a single generation, flying in June and July, when the species will come to light.

It is believed to feed on Common Reed, probably internally in the stems.

A local species, occurring mainly in the fens and marshes of East Anglia and south-eastern England. In the Butterfly Conservation's Microlepidoptera Report 2011 this species was classified as Nationally Scarce A.

Rare in Leicestershire and Rutland, the specimen recorded at Rutland Water on 1st July 2017 was the first record for VC55.