1a upper- or lower-surface gallery or blotch; larva a maggot => 2

1b full depth gallery or blotch; larva with chitinised head => 8

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

2a pupation within the mine => 3

2b pupation external => 5

3a corridor pinnately branched, main branch overlying the midrib; mine starts with a very narrow, usually lower-surface, corridor: Liriomyza strigata

3b corridor unbranched, not associated with the midrib, without an lower-surface beginning => 4

4a frass in strings; larva: rear spiraculum with 3 papillae: Liriomyza trifolii

4b frass (partly) in isolated grains; rear spiraculum with 8-11 papillae: Phytomyza erigerophila

5a primary blotch (preceded by a short corridor that usually gets overrun later) => 6

5b corridor, sometimes a secondary blotch => 7

6a frass black, rather coarsely grained, very little in quantity: Calycomyza humeralis

6b frass brown, very finely grained, more abundant: Calycomyza solidaginis

7a frass grains separated by about their own diameter; corridor normal in length and width: Chromatomyia cf. syngenesiae

7b frass grains much further apart; corridor unusually long and narrow, making several loops through the leaf: Ophiomyia maura

8a larva without thoracic feet: Orthochaetes insignis & setiger

8b thoracic feet present => 9

9a mine associated with a silken tube under the leaf => 10

9b no silken tube => 11

10a lowland species: Scrobipalpula psilella

10b species of higher elevations: Gnorimoschema valesiella

11a larve mines all its life (?): Scrobipalpula diffluella

11b older larvae between spun leaves => 12

12a mines are made by larvae that hide between spun leaves: Scrobipalpula ramosella

12b the (young) larvae live within the mine => 13

13a arva: pinacula colourless (the bases of the setae themselves are black): Cnephasia incertana

13b pinacula black: Cnephasia stephensiana