Ectoedemia intimella

Wingspan about 6 mm.  The adult is mostly blackish with a slight purple sheen and an obvious white or creamy blotch. The head is orange or yellowish. The larvae mine the leaves of sallow (Salix), especially S. caprea and S cinerea, initially galling the leaf petiole before moving to the the midrib of the leaf. Subsequently it mines into the leaf-blade, forming a distinctive blotch which often contains two lines of frass.   The larva can be found in fallen leaves into December, feeding in 'green islands'.

Adult Leafmine

Adults: Determination by Genitalia Examination (gen. det.) Required.  

Leafmine: Good photograph required preferably backlit to show frass within the mine and larva if present.  Please also state the host species.

Areas where the host willows occur, especially Goat Willow (Salix caprea).

Adults are on the wing in June, in a single generation. Leafmines may be found between July and November.

In the Butterfly Conservation's Microlepidoptera Report 2011 this species was classified as local.

Not frequently recorded in Leicestershire and Rutland, although it may be overlooked.

http://www.leafmines.co.uk/html/Lepidoptera/E.intimella.htm

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/lepidoptera/monotrysia/nepticuloidea/nepticulidae/ectoedemia/ectoedemia-intimella/