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

1b larva a maggot; mine upper- or lower-surface, greenish when lighted from behind => 5

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

2a larva with prolegs; older larvae live free; mine small => 3

2b no prolegs; larve mines livelong; mine not that small, a corridor => 4

3a mine roundish; older, free living, larvae under the leaf: Plutella xylostella

3b mine of undefinite shape; free living larvae among spun leaves: Cnephasia incertana

4a larva witthout feet: Ceutorhynchus minutus

4b larva with thoracic feet: Phyllotreta nemorum

5a mine a corridor, in the end widening into an irregular blotch => 6

5b a corridor from start to end => 7

6a frass powdery, in green clouds in remote corners of the mine: Scaptomyza flava

6b frass black, in grains or strings: Liriomyza xanthocera

7a corridor pinnately branched, its main and side branches on top of the midrib and lateral veins: Liriomyza strigata

7b several short corridors, starting from the midrib: Ophiomyia beckeri

7c corridor independent of the leaf veins => 8

8a pupaption within the mine, in a, generally lower-surface, pupal chamber: Chromatomyia horticola

8b pupation external => 9

9a larva: rear spiraculum with 7-12 papillae: Liriomyza bryoniae

9b rear spiraculum with 3 papillae: Liriomyza brassicae