1a mine small, irregular, full depth; the larva, with clear head and feet, later lives free among spun leaves: Cnephasia incertana

1b mine not unusually small or irregular; the larva, a maggot, mines all its life => 2

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

2a corridor from start to end, nowhere strongly widened; mountain species: Phytomyza aconitella

2b blotch, or a corridor that at least locally is strongly widened => 3

3a blotch without a trace of a preceding corridor; frass irregularly scattered, often cloudy; also in gardens: Phytomyza aconiti

3b mine begins with a distinct corridor (may be overrun by the later blotch, then recognisable only by the frass line) => 4

4a corridor, locally strongly widened; frass scattered through the mine, in coarse lumps; Mediterranean species, on Delphinium staphisagria: Ophiomyia delphinii

4b short corridor, continued in, and often overrun by, a blotch; most frass in the apical part of the mine, in short strings; also in gardens: Phytomyza aconitophila