1a mine full depth; larva with chitinised head => 2

1b mine upper- or lower-surface (small patches sometimes full depth); larva a maggot => 4

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

2a smll blotch, < 1 cm; older larvae live free: Plutella xylostella

2b mine > 1 cm, corridor or blotch; larva remains in the mine until pupation => 3

3a larva without feet; mine an untidy corridor: Ceutorhynchus minutus

3b larva with thoracic feet; a corridor that in the ends widens to a blotch: Phyllotreta nemorum

4a corridor from start to end => 5

4b irregular blotch, preceded buy a narrow corridor (may be overrun by the blotch) => 7

5a broad, pinnately branched corridor, its main branch overlying the midrib: Liriomyza strigata

5b corridor litle branched, not pinnate, not associated with the midrib => 6

6a puparium in the mine, in a, usually lower-surface, pupal chamber; frass in discrete grains: Chromatomyia horticola

6b prior to pupation the mine is vacated through a semicircular exit slit; frass in thread fragments: Liriomyza brassicae

7a frass in thread fragments; mine in May-June: Liriomyza xanthocera

7b frass powdery, in blackish-green clouds; mine in May-October: Scaptomyza flava