Eriocrania unimaculella

Wingspan 10mm. This species has a silvery, rather than golden, tornal spot which can help distinguish it from similar species; however the adults can be very difficult to tell apart and it is best to rear from larvae or to refer to genitalia for identification.

All Eriocraniidae leafmines have spaghetti-like frass, in long threads. The larva when fully developed has a dark brown head capsule.  This is retracted into the transparent prothorax but the dark head shows through as two dark spots o nthe pronotum.  Two short lateral projections on the 1st adbominal segment are sometimes visible.  Immature larvae have dark ventral spots on thorax and 1st abdominal segment. (ref: Bladmineerders.nl, accessed March 4th 2025)

Adult leafmine+larva

The mine can only be recorded if mature larvae are present.  Provide photos of larva outside the mine as well as a blacklit photo of the mine in the leaf; note the host.

Around Birch.

The adults fly in sunshine during March and April.

The larvae feed on Birch, causing a blotch at the edge of the leaf. . Mines can be found during late April to late May.

Well distributed over much of Britain but not particularly common. In the Butterfly Conservation’s Microlepidoptera Report 2011 this species was classified as local.

It appears to be uncommon in Leicestershire and Rutland, where there are few records. L&R Moth Group status = D (rare or rarely recorded).

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

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/lepidoptera/glossata/eriocraniidae/heringocrania/heringocrania-unimaculella/