1a mine full depth, (almost) without frass, with an opening through which the larva has entered => 2

1b mine full depth, with clear amounts of frass, no recognisable opening: Ceutorhynchus minutus

1c mine lower- or upper-surface, with frass; no opening => 5

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

2a larva mines from a helicoidal case: Apterona gracilis

2b larva does not mine from a case => 3

3a mine < 1 cm; older larvae live free under the lea: Plutella xylostella

3b mine larger; larvae mine facultatively, either life-long, or older larvae among spun leaves => 4

4a mine begins as a broad corridor: Selania leplastriana

4b mine a broad blotch from the start on: Hellula undalis

5a short gallery, that ends or begins on a thick vein; the larva essentially lives as a borer in the veins, petiole, or stem => 6

5b the larva does not mine in (though sometimes upon!) the veins => 7

6a larva a maggot: Phytomyza rufipes

6b larva with chitinised head: Ceutorhynchus pallidactylus

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

7b blotch, or little, not pinnately, branched gallery; mine not determined by the leaf venation => 8

8a gallery from start to end => 9

8b one or more galleries, ending in a common blotch: Scaptomyza flava

9a pupation within the mine, in a, generally lower-surface, pupal chamber; frass in well-spaced grains: Chromatomyia horticola

9b pupation external; frass in strings: Liriomyza brassicae