Wingspan 11-14 mm.
The eggs of this species are laid on the florets of Jointed Rush.
The larva forms a case from silk and the remains if the seed capsule, 6-7mm in length. The larvae overwinter, away from the feeding places, and pupation occurs in May and June, with the adults emerging from mid-June to August.
The moth is found in damp locations throughout the British Isles.