Selinum cambridge milk-parsley
incl. Cnidium.
Dichotomous table for leafminers
1a mine with a short lower-surface initial corridor: Phytomyza selini
1b mine entirely upper-surface => 2
1c galls, etc => Tables for all parasites per species
2a mine with one or more elongated full depth patches; larva: rear spiracula with 14-16 papillae: Phytomyza mylini
2b mine of constant depth; rear spiracula with 22 papillae: Phytomyza thysselini
Not included in the key: Phytomyza chaerophylli (occurrence on this plant dubious).