1a fleck mine, the larva mines from a transportable case => 2

1b gallery or blotch mine; the larva mines from within => 3

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

2a brownish black sheath case: Coleophora albitarsella

2b composite leaf case (occurence on this host plant not quite certain): Coleophora pennella

3a mines tiny, usually several on a leaf, of undefinite shape; larvae with chitinised head => 4

3b mines not remarkably small, one per leaf, a gallery or blotch; larva a (seemingly) headless maggot => 6

4a larvae colourless, without feet; older larvae live free and cause window feeding: Phytosciara halterata

4b larvae dark in colour, with thoracic feet; older larvae live free among spun leaves => 5

5a larva: pinacula colourless (the bases of the setae themselves are black) : Cnephasia incertana

5b pinacula black: Cnephasia stephensiana

6a long, hardly widening corridor, abruptly widening into (and later overrun by) a large blotch: Amauromyza labiatarum

6b corridor from start to end, or becoming a secondary blotch => 7

7a corridor not contorted: Chromatomyia horticola

7b corridor strongly contorted, often a secondary blotch: Phytomyza lycopi