1a mine shallow, greenish when lighted from behind; larva a maggot: Agromyza idaeiana

1b mine full depth, not greenish in transparency; larva with chitinised head => 2

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

2a corridor till the end: Stigmella aurella

2b corridor widens into definite blotch => 3

3a mine begins at a shining egg shell; then a contorted corridor, that finally widens into a blotch; larva without feet: Ectoedemia agrimoniae

3b no egg shell to be seen; the mine widens almost immediately to a blotch; larva with well-developed thoracic legs: Fenella nigrita