Wingspan 8 mm to 10 mm. A plain looking micromoth with a pale mottled brown appearance.

The larva feed on Bindweed and related species, initially in an inconspicuous narrow and very contorted gallery.  The egg is oval, not round as with Stigmella species.

Later instars leave the gallery and feed in a transparent blotch mine.   The rear end of the larva sticks out of the undersurface of the leaf, and threads of frass hang beneath the mine, caught in a loose net of silk.   Early instar larvae from the galleries are whitish; later instars have purplish spots and markings.

Other insect species cause feeding 'windows' in bindweed; check for early galleries, larvae and frass caught below mine

Adult leafmines

Backlit photos of mines; note host

Various habitats, especially where the larval foodplant is found.

The adults occur in two generations; in August and October to May, being 'somnolent' in the winter months.

The distinctive larva feeds on bindweeds mining the leaves.

Widespread in southern Britain, but it is subject to huge fluctuations in numbers. In the Butterfly Conservation’s Microlepidoptera Report 2011 this species was classified as local.

It seems to have become more frequent recently in Leicestershire and Rutland although it is often the larval leaf mines that are recorded.

http://www.leafmines.co.uk/html/Lepidoptera/B.somnulentella.htm

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/lepidoptera/ditrysia/yponomeutoidea/bedelliidae/bedellia/bedellia-somnulentella/