1a mine in the petiole or in te lower part of the midrib => 2

1b mine in the leaf or in the tip of the midrib => 4

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

2a mine in the top section of the midrib, causing the upper part of the leaf wither and become necrotic: Chirosia nigripes

2b mine in the lowest part of the midrib and/or the petiole => 3

3amine extending from the lower branches of the leaf down to ground level; larva: upper of two backward pointing processes of the cephalic skeleton bifid: Chirosia albitarsis

3b mine only in the lower part of the petiole; upper of two backward pointing processes simple: Chirosia crassiseta

4a mine in the midrib and blade of the leaf tip, causing the leaf to curl backwards: Chirosia grossicauda

4b mine not exclusively in the leaf tip, not causing deformation => 5

5a at the start of the mine, at the leaf underside along the midrib an elliptic egg shell; blotch, extending over several leaf segments: Chirosia cinerosa, histricina

5b no egg shell visible; corridor or secondary blotch => 6

6a frass fine-grained, locally absent; larva with chitinised head: Psychoides verhuella

6b frass in lumps and strings, nowhere absent; larva a maggot: Phytoliriomyza hilarella and pteridii