1a mine small, full depth; larva with feet and sclerotised head =>2

1b mine larger, upper- or lower-surface, greenish in transparancy; larva a maggot => 3

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

2a larva: pinacula colourless (only the base of the setae black): Cnephasia incertana

2b pinacula black: Cnephasia asseclana

3a primary blotch; may be preceded by a corridor => 4

3b corridor till the end, may form an incomplete secondary blotch => 5

4a no preciding corridor: Hydrellia griseola

4b mine preceded by a corridor, with frass in two rows (the corridor may have been overrun by the later blotch, but will remain recognisable in the frass pattern); unusual on this hostplant: Amauromyza labiatarum

5a pupaption within the mine, in a, generally lower-surface, pupal chamber; frass in discrete grains: Chromatomyia horticola

5b pupation outside the mine; frass at least partly in strings or pearl chains => 6

6a corridor pinnately branched, main branch overlying the midrib; never a secondary blotch: Liriomyza strigata

6b corridor little branched, independent of the leaf venation; often een secondary blotch: Liriomyza bryoniae