1a mine small; older larva free among spun leaves: Cnephasia incertana

1b mine not unusually small; larva mines all its life => 2

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

2a mine in the end a primary or secondary blotch => 3

2b mine a corridor until the end => 6

3a larva a maggot => 4

3b larva with thoracic feet and a sclerotised head => 5

4a mine very shallow, almost invisible in transparancy; pupation as a rule within the mine: Phytomyza sedicola

4b mine deep, transpatrant; pupation outside the mine: Cheilosia semifasciata

5a leaf strongly disfigured by the mine; larva grey: Cnephasia lineata

5b leaf not disfigured; larva pale yellow: Glyphipterix umbilici

6a corridor very narrow; frass in pearl strings; larva a maggot: Liriomyza umbilici

6b corridor coarser; frass sometimes in a loose central line, sometimes locally absent; larva with chitinised head: Orthochaetes insignis