1a frass in discrete grains; puparium formed in a, usually lower-surface, pupal chamber: Chromatomyia cf. syngenesiae

1b frass in strings; pupation after the larva has left the mine, making a semicircular exit slit in the epidermis => 2

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

2a gallery pinnately branched, main and side branch on top of the midrib and lateral veins: Liriomyza strigata

2b gallery and branching independent of the leaf venation paptern => 3

3a larva: rear spiraculum with 7-12 papillae; European species: Liriomyza bryoniae

3b rear spiraculum with 3 papillae; tropical species, accidentally introduced in Europe; in temperate regions mainly in greenhouses: Liriomyza trifolii