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

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

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

2a mine rather opaque, not limited to the leaves: Psylliodes marcida

2b mine very transparant, limited to the leaves => 3

3a mine small, < 1 cm; frass in discrete grains; larva, with abdominal and thoracic feet, later lives free => 4

3b mine > 1 cm, frass lumpy; larva without feet: Ceutorhynchus minutus

4a the free living larve among spun leaves: Cnephasia incertana

4b the free living larva under the leaves: Plutella xylostella

5a corridor from start to end => 6

5b mine in the end widened, blotch-like => 7

6a pupation within the mine, in a, generally lower-surface, pupal chamber; frass in discrete grains: Chromatomyia horticola

6b pupation outside the mine; frass in strings: Liriomyza brassicae

7a frass in black granules; larva: rear spiraculum with 3 papillae: Liriomyza xanthocera

7b frass powdery, in blackish green clouds; rear spiraculum drawn into a point, virtually a single papilla: Scaptomyza flava