1a mine associated with a silken tube at the outside; larva with thoracic feet and a recognisable head => 2

1b mine without a silken tube; larva a maggot => 3

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

2a tube on the ground, covered with dirt: Scrobipalpula psilella

2b tube higher in the vegetation: Scrobipalpula diffluella

3a clear corridor, without conspicuous feeding lines: Phytomyza homogyneae

3b corridor, but large sections widened to a blotch; feeding lines very conspicuous: Acidia cognata