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

1b mine upper- or lower-surface, greenish when lighted from behind; larva a maggot => 4

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

2a frass in grains; larva with prolegs; older larvae live free: Plutella xylostella

2b frass, at least partly in thread fragments; larvae remain in the mine till just before pupation => 3

3a larva with thoracic feet; corridor mine, widening into a blotch: Phyllotreta nemorum

3b larva without thoracic feet; corridor, often branched, only weakly widened: Ceutorhynchus minutus

4a corridor or (partly) a secondary blotch => 5

4b final section of the mine a primary blotch, more or less oriented on the midrib => 6

5a pupation within the mine in a, generally lower-surface, pupal chamber; frass in dispersed grains; never a secondary blotch: Chromatomyia horticola

5b pupation outside the mine; frass partly in pearl chains; final section of the mine usually a secondary blotch: Liriomyza bryoniae

6a frass in grains and thread fragments; larvae in May-June: Liriomyza xanthocera

6b frass powdery, in green clouds; larvae from May till October: Scaptomyza flava