Foeniculum fennel
Dichotomous table for leafminers
1a larva darkly coloured, with well recognisable head; older larvae live free among spun leaf segments: Cnephasia incertana
1b larvae are colourless maggots; they mine until just before pupation: Phytomyza ferulae
1c galls, etc => Tables for all parasites per species
Not included in the key:: Ptochomyza czernyi