The monophyly of this highly diverse group can be based on the peculiar stick-like shape of the distal part of the gonites of male genitalia (Chr syngenesiae hypandrium.pct, Pseu europaea epandrium.pct), which are fused with the hypandrium.
Adults, external
Only some of the phytomyzine genera contain species of economic importance, therefore some genera are omitted from the present CD-ROM.
Without dissecting genitalia, Phytomyzinae can be easily identified by the wing venation: Unlike Agromyzinae, the R1 is not apically thickened and not coalesced with the subcosta agr-phy-wing.pct. The subcosta can be either well developed, extending to the wing margin, or strongly reduced. The missing thickening of the R1 has to be interpreted as a plesiomorphic (ancient) character state. This feature cannot characterize the taxon but is useful for identification.
Immature instars
The larvae can be recognized by the basal part of the cephalopharyngeal skeleton. The lower part of the dorsal arm is reduced or missing, sometimes long and needle-like agr-phy-larva.pct. Usually the larval mandibles are asymmetrical with the right mandible being larger than the left one Chr nigra Larva SEM1.pct. Some typical cephalopharyngeal skeletons of Phytomyzinae: phytomyzinae larva.pct.
Bionomics
Most species are leaf miner, some of them are specialized to the leaf shaft of grasses or petioles. Some species feed on seeds and stems.