Many Stigmella species are almost impossible to identify as adults, but are easier to record from the leafmines created by their larvae.

The larvae of Stigmella incognitella mine the leaves of Apple. The mines are found between veins. The initial gallery is narrow and then forms an orange-brown blotch.   

Stigmella malella, also on Apple

Adult Leafmine

Records of the leafmine should include a backlit image of the mine showing the frass pattern as well as a picture of the leaf.  The record should also include a note of the host plant on which the leafmine was found.

Where Apple is found.

Leafmine: June-July, October-November.

Status in Britain is difficult to determine due to lack of records, but the records we have suggest this species may be widespread, if local in the southern half of Britain at least.  In the Butterfly Conservation's Microlepidoptera Report 2011 this species was classified as local.

Rarely recorded in Leicestershire and Rutland.

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

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