Bucculatrix bechsteinella is a small moth with a wingspan of 7 to 9 mm. It is pale buff with brown markings. The leafmine produced by the larva is usually on Hawthorn, and is small and in a vein axil, with blackish frass.  The exit gallery is clear, and angular in shape. 

Leafmines can resemble early mines of Stigmella species, or Paraswammerdamia nebulella (ref.: British leafminers)

Adult leaf mine

Clear backlit photos of mine, including exit gallery

The moth occurs in well wooded areas.

The adults emerge in May and early June.

The larvae of this species feed in July and August, initially mining the leaves of Crataegus, Pyrus, Malus or Sorbus species, in a short, contorted gallery. As the larva develops it leaves the mine to feed externally, creating windows on the upperside of the leaves. Pupation occurs in a ribbed white cocoon spun on debris. The winter is passed in this stage.

Found locally throughout England and southern Scotland. 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/B.bechsteinella.htm

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/lepidoptera/ditrysia/gracillarioidea/bucculatricidae/bucculatrix/bucculatrix-bechsteinella/