1a fleck mine; larva mines from a case => 2

1b corrdor or blotch, containing frass; larva not in a case =>3

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

2a hole in the mine not neatly round, margin simple; larva in a helicoidal case, covered with grains of sand: Apterona helicoidella

2b hole exactly round, margin with a fine fringe of stubbles of bitten silk; case not helicoidal, covered with leaf fragments: Coleophora colutella

3a larva with sclerotised head; older larva lives free among spun leaves: Aproaema anthyllidella

3b larva, a maggot, spends its entire life in the mine => 4

4a pupation within the mine, in a, generally lowe-surface, pupal chamber; frass in isolated grains: Chromatomyia horticola

4b pupation outside the mine; frass in strings or pearl chains, or in a broad green band => 5

5a a corridor, its largest part following the leaf margin, followed by a large primary blotch: Phytoliriomyza variegata

5b a corridor till the end, not associated with the leaf margin, may terminate in an indistinct secondary blotch => 6

6a frass in strings: Liriomyza bryoniae

6b frass in a broad green band: Liriomyza congesta