1a fleck minel arva in a helicoidal case: Apterona helicoidella

1b corridor or blotch => 2

1c galls, etc => Tables for all parasites per species

2a mine small, irregular => 3

2b mine > 1 cm, a definite corridor or blotch => 4

3a last abdominal segment with a black anal comb: Cnephasia asseclana

3b no anal comb present: Cnephasia stephensiana

4a Oviposition site covered by a shining black drop of dried secretion: Trachys troglodytiformis

4b no such drop => 2

5a corridor, sometimes quite broad, overlying midrib and side veins => 6

5b long, narrow corridor, closely following midrib and/or side veins: Bucculatrix lavaterella

5c mine not associated with leaf venation => 7

6a corridor rather narrow, not varying in depth and width: Liriomyza strigata

6b corridor strongly varying in width and depth; especially on top of the midrib sometimes almost blotch: Liriomyza xanthocera

7a gallery from start to end (perhaps a secondary blotch) => 8

7b blotch, possibly preceded by a gallery part => 9

8a frass in isolated grains; pupation within the mine, in a, generally lower-surface, pupal chamber: Chromatomyia horticola

8b frass in short strings; pupation external: Lyriomyza bryoniae

9a blotch preceded by an intestine-like zigzagging gallery: Agromyza brunnicosa

9b blotch preceded by a short simple gallery, the usually is overrun by the later blotch: Dialectica hedemanni