1a larva with thoracic feet and a distinct head => 2

1b larva a maggot => 6

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

2a mine in the end a large blotch; larvae mine all their life => 3

2b mine small, very irregular; older larvae live free, among spun leaves => 4

3a mine contains no frass: Micrurapteryx kollariella

3b mine contains much frass: green at first, then black, in concentric arcs: Leucoptera laburnella

4a larva: pinacula colourless (but the base of the setae themselves black): Cnephsia incertana

4b pinacula black => 5

5a larva: below/behind the anus a chitinous comb: Cnephasia asseclana

5b no anal comb present: Cnephasia stephensiana

6a corridor that more or less closely follows the leaf margin until the leaf tip, then suddenly widens into a blotch (unusual species on this hostplant) => 7

6b mine not hook-like => 8

7a corridor very closely following the leaf margin; secondary feeding lines conspicuous: Agromyza demeijerei

7b corridor loosely following the leaf margin; no secondary feeding lines apparent: Agromyza johannae

8a corridor from start to end => 9

8b corridor, widening into a blotch => 12

9a puparium in the mine, in a, usually lower-surface, pupal chamber: Chromatomyia horticola

9b larva leaves the mine before pupation through a semicircular exit slit => 10

10a corridor pinnately branched, main branch overlying the midrib: Liriomyza strigata

10b corridor little branched, not associated with the midrib => 11

11a frass in two rows of grains or strings: Lyriomyza bryoniae

11b frass in a broad green central band: Liriomyza congesta

12a frass powdery, in green clouds along the margins of the mine: Scaptomyza graminum

12b frass in big black grains, partly hanging together in pearl chains: Liriomyza xanthocera