1a short gallery, that either ends of begins on the midrib or a thick side vein => 2

1b mine different => 3

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

2a larva a maggot; the corridor begins on the leaf; then the larva enters a side vein, from there goes into the midrib: Phytomyza rufipes

2b larva with well recognisable head; the larva bores in the midrib, from there enters the stem. Occasionally short excursion are made from the midrib into the blade: Ceutorhynchus pallidactylus

3a larva a maggot => 4

3b larva with well recognisable head => 7

4a mine a gallery from start to end => 5

4b mine eventually a large irregular blotch => 6

5a gallery pinnately branched, lying on top of the midrib and side veins; pupation external: Liriomyza strigata

5b gallery not pinnate, not associated with the venation; pupation internal, in a, generally lower-surface, pupal chamber: Chromatomyia horticola

6a frass in black strings: Liriomyza xanthocera

6b frass powdery, in green “clouds”, often visible only after opening the mine: Scaptomyza flava

7a larvae with prolegs; they mine only briefly, then continue living free under the leaf: Plutella xylostella

7b the larvae, without prolegs, mine all their life => 8

8a larva with thoracic legs: Phyllotreta nemorum

8b no thoracic legs: Ceutorhynchus minutus