Adults are about 2.5 mm and may be dark metallic green, bronze, copper, blue or violet.  The larvae mine the leaves of various plants, and are short, yellow, and with a black head.

Adult  Leafmine

Adult and Leafmines: Unless identified by a recognised expert, a photo is required. If the photo doesn't show the key ID features then in the comments box describe the size and identifying characters you have observed.

Various habitats including well wooded areas.

The leafmines appear from spring to early summer.  Adults are usually recorded from March to September.

Overwintering adults are sometimes found in moss and leaf litter.

Widespread and fairly frequent, particularly in the southern half of Britain.

Fairly frequent in Leicestershire and Rutland.