Wingspan 9 - 10mm, one of the smaller Monochroa species. Elongate and ochreous brown with four pale spots along the costal cilia. 

Similar to Monochroa moyses, and a dark form of Monochroa suffusella is known from Wicken Fen.

Dissection is required for all new-site records, and otherwise for all but the most pristine specimens. Ensure good photographs obtained and retain the specimen pending advice from the CMR.

Reed-swamps, riverbanks, edges of pools and lakes, fens, marshes and small, wet ditches.

Single-brooded, with adults on the wing during June and July.

The larvae mine the leaves of Carex riparia (Greater Pond-sedge), and to a lesser extent Carex acutiformis (Lesser Pond-sedge).

Scarce, although possibly under-recorded. Generally in the south and south-east England. In Butterfly Conservation's Microlepidoptera Report S12-02 (Jan 2012) this species was classified as pRBD1.

Rare in Leicestershire and Rutland; the Whetstone record of 13th June 2025 is the first for VC55.

Monochroa arundinetella | Gelechiid Recording Scheme