Asperugo madwort
Dichotomous table for leafminers
1a corridor from start to end: Chromatomyia horticola
1b eventually a large blotch => 2
1c galls, etc => Tables for all parasites per species
2a mine flat; larva a maggot: Agromyza abiens
2b mine strongly puckered; larva with thoracic feet and a distinct head: Cnephasia lineata