Wingspan 7- 8 mm. This can be a difficult group to distinguish.

The larva feeds on Hazel, causing a lower surface tentifrom mine; the upper surface is usually netted brown, with a green patch on top. The larva is pale yellow/greyish (due to a speckling of minute black warts) with dark markings on head

leafmine can be similar to Parornix devoniella

Adult Leafmine

Photograph the mine and note host species; if in doubt check larva.  

Found in various habitats.

Moth has two generations and may be found flying in May and August.

Larva forms a long mine between the veins of a Hazel (Corylus) leaf and is strongly arched. The leaf mines may be found in July and then September to October. Larva overwinters as a pupa in a cocoon.

This moth is common and found throughout Britain. In the Butterfly Conservation’s Microlepidoptera Report 2011 this species was classified as common.

Fairly frequent in Leicestershire and Rutland, but may be under recorded.

http://www.leafmines.co.uk/html/Lepidoptera/P.nicellii.htm

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/lepidoptera/ditrysia/gracillarioidea/gracillariidae/lithocolletinae/phyllonorycter/phyllonorycter-nicellii/