Stigmella lapponica

Wingspan 5 to 7 mm. The adults are coarsely-scaled and dull greyish-brown with an indistinct creamy fascia. The larva mine the leaves of Birch. The mine is long, filled with green frass to ¼, and then linear. The larva is a greenish white, head brown.

Stigmella confusella has narrow linea frass throughout mine

Adult Mine

Adult: Unless identified by a recognised expert, a photo is required and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.

Leafmine: When recording the mine, provide backlit photographs and note the host

Associated with Birch.

Adults of this single-generation species are on the wing in May.  Tenanted mines may be encountered from mid-June to early July.

Widespread and fairly frequent in Britain. In the Butterfly Conservation's Microlepidoptera Report 2011 this species was classified as common.

Infrequently recorded in Leicestershire and Rutland.

http://www.leafmines.co.uk/html/Lepidoptera/S.lapponica.htm

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/lepidoptera/monotrysia/nepticuloidea/nepticulidae/stigmella/stigmella-lapponica/