1a larva with thoracic feet and chitinised head => 2

1b larva a maggot => 3

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

2a mine full depth; larva with prolegs: Pseudodineura parvula

2b mine upper- or lower-surface, greenish when lighted from behind; larva without prolegs: Argopus nigritarsis

3a primary blotch => 4

3b corridor, may form a secondary blotch => 5

4a larva: rear spiraculum with 11-14 papillae: Phytomyza socia

4b rear spiraculum with 16-17 papillae: Phytomyza pulsatillicola

5a puparium almost always formed within the mine: Phytomyza ignota

5b pupation always outside the mine: Phytomyza pulsatillae