1a mine full depth, transparent, small (but sometimes many together); larva with thoracic feet and a sclerotised head; older larvae only with head and thorax inserted in the mine, or entirely free => 2

1b mine upper- or lower-surface, greenish in transparency, larger, corridor or blotch; larva a maggot => 5

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

2a many mines together in axils of the major veins: Epermenia chaerophyllella

2b mines single => 3

3a larva: pinacula colourless (only the bases of the setae black): Cnephasia incertana

3b pinacula black => 4

4a larva: segment 10 with an anal comb: Cnephasia asseclana

4b no anal comb: Cnephasia stephensiana

5ablotch, usually containing several larvae (rare on this host plant) => 6

5bcorridor, may be considerably widened in the end => 8

6alarva big, coarse; cephalic skeleton with an anteriorly directed projection; rear spiraculum with 3 papillae: Euleia heraclei (common species) or Cryptaciura rotundventris (rare species)

6blarva small, tender; cephalic skeleton without such a projection; rear spiraculum with ca. 20 papillae => 7

7alarva: above the entrance to the buccal cavity a dark band with fine warts (species from N and C Europe): Phytomyza aegopodii

7bno such band: Phytomyza chaerophylli

8amine starts with a quite faint lower-surface corridor (rare on this host plant): Phytomyza angelicastri

8bmine upper-surface throughout => 9

9a corridor following the leaf margin for long ends; frass grains big, very numerous, blackish green, often in pearl strings: Phytomyza obscurella

9bcorridor not associated with leaf margin; frass grains smaller, less numerous, not connected => 10

10aspring mine (April – early June): Phytomyza pubicornis

10bsummer mine (after mid June): Phytomyza podagrariae