1a corridor < 1 cm long, full depth; larva with feet and chitinised head => 2

1b mine longer, upper-surface, larva a maggot => 3

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

2a larvae laterally with a bright yellow length line: Depressaria daucella

2b larvae more or less uniformly coloured: Epermenia chaerophyllella

3a corridor mine => 4

3b blotch mine, may start with a short and wide corridor => 6

4a corridor short, initial ppart lower-surface, later upper-surface; exit slit in upper epidermis: Phytomyza cicutae

4b corridor several cm long, fully upper-surface; exit slit in lower epidermis => 5

5a corridor follows the leaf margin; frass partly in pearl chains: Phytomyza virosae

5b corridor free in the leaf; frass usually in isolated grains: Phytomyza pastinacae

6a large blotch with conspicuous primary and secondary feeding lines; larva: rear spiracula with 3 papilla: Euleia heraclei

6b small blotch without apparent feeding lines; rear spiracula with >3 papillae => 7

7a mine small, upper-surface throughout, usually in the tip of a leaf segment; frass in black lumps: Phytomyza cicutivora

7b mine larger. usually with some full depth patches; frass in grains, locally pearl chains: Phytomyza mylini