1a whitish or mottled, irregular blotch overlying the midrib => 2

1b upper- or lower-surface corridor => 3

1c full depth corridor or blotch (not associated with the leaf venation) => 5

1d gallen etc => Tabellen voor alle parasieten per soort

2a frass powdery, in green “clouds”: Scaptomyza flava

2b frass in back grains or strings: Liriomyza xanthocera

3a pupation within the mine, in a, usually lower-surface, pupal chamber; frass in discrete granules: Chromatomyia horticola

3b pupation outside the mine; frass in strings => 4

4a mine pinnately branched, main branch overlying the midrib: Liriomyza strigata

4b mine not associated with the leaf venation: Liriomyza brassicae

5a miine small (< 1 cm), often irregular; frass in granules; larva, with prolegs, later lives free => 6

5b mijn > 1 cm, frass in strings or lumps; larva, without prolegs, remains in the mine all its life => 7

6a mine contains a little silk; free living larvae among spun leaves: Cnephasia incertana

6b mine contains no silk; free living larvae at the leaf underside: Plutella xylostella

7a frass in thread fragments; mine an untidy corridor; larva without thoracic feet: Ceutorhynchus minutus

7b frass in lumps; mine an irregular blotch; larva with thoracic feet: Phyllotreta nemorum