1a mine full depth; larva with chitinised head => 2

1b mine upper- or lower-surface; larva a maggot => 5

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

2a mine very small; older larvae live free among spun leaves => 3

2b mine of normal size; older larve either in a leaf roll, or mining all its life => 4

3a pinacula colourless (but the bases of the setae are black): Cnephasia incertana

3b pinacula black: Cnephasia asseclana

4a elongated blotch; only in spring, on Campanula persicifolia: Orophia ferrugella

4b mine, at least its first part, a definite corridor: Orthochaetes insignis

5a narrow corridor, descending to the petiole, then to the bark of the stem: Ophiomyia eucodonus

5b mine larger, not leaving the lea => 6

6a pupation in the mine in a, usually lower-surface, pupal chamber: Chromatomyia horticola

6b pupation outside the mine => 7

7a branching corridor, positioned over the midrib and the more heavy lateral veins: Liriomyza strigata

7b no association with the leaf venation => 8

8a upper surface blotch, preceded by a short, narrow corridor; larvae usually communal: Amauromyza gyrans

8b corridor; larva solitary => 9

9a corridor shallow, whitish; frass in discrete grains: Phytomyza campanulae

9b corridor deeper, greenish; frass in the first section of the mine in pearl chains: Phytomyza rapunculi