Eriocrania sparrmannella

Wingspan 10 to 13 mm.  The adult moths are very attractive when viewed closely, having a metallic golden ground colour, intensely speckled with purple and blue. There is also a golden tornal spot.

Like related species, the larva mines a leaf of the foodplant (Birch), starting with a narrow gallery, widening abruptly into a blotch filled with filament-like threads of frass.  The mine begins later than other Eriocrania, in the centre of the leaf.  The larva has two cloudy brown spots visible through the pronotum, but these can be very difficult to see.

Other Eriocrania on Birch.  E salopiella has very similar mines and larvae, but they start earlier in the season.

Adult Leafmine+larva

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.  The specimen should be retained as genitalia determination may be required for adults of this species.

Leafmine: The mine (backlit) and larva must be photographed for this species. Only tenanted mines can be identifed. 

Areas where Birch is found.

Adults fly from late April into May. This is followed by the leafmines on Birch. Eriocrania sparrmannella is the latest of the Betula feeding Eriocraniidae, with larvae feeding from mid-June into August.

The species is locally but well distributed throughout Britain. In the Butterfly Conservation's Microlepidoptera Report 2011 this species was classified as local.

Rare or rarely recorded in Leicestershire and Rutland.

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

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/lepidoptera/glossata/eriocraniidae/eriocrania/eriocrania-sparrmannella/