Japanagromyza Sasakawa, 1958
This genus is the sister group of the Ophiomyia group (Tribe Ophiomyiini).
The following characters, which are further explained below can be interpreted as apomorphies: surstyli elongated, the shape of aedeagus, cleaning comb, posterior spiracles of larvae.
Adults
Body either subshining or covered with pubescence, the surface below the pubescence normally bluish or greenish shining. Four frontorbital bristles present, of these the distal one inwards directed. Lunule black, often covered with fine silvery pubescence, frons hardly projecting above eyes. As in Ophiomyiini, two, postsutural dorsocentral bristles present; acrostichals numerous, prescutellar bristles normally present.
2-3 bristles on second tibiae present in posteromedian position; first tibia (often/always) with longer posteromedian bristle. Wings rather short and broad with complete venation. A cleaning comb present at inner side of distal end of (hind) tibiae (Tschirnhaus, 1991), second and third femora more or less strongly thickened, often conspicuously hollowed. However, this character may be often not recognizable on dried legs. Wings normally rather broad. Tegulae can be dark or light; squamae have usually light hairs and light margins.
Male terminalia (J inaequalis genitalia.pct)
Cerci conspicuously enlarged and usually very broad (J inaequalis epandrium.pct), probably with clasping function. Apices of epandrium (Surstyli) are not articulated but long and projecting.
Insides of the two epandrium-apices are large and fused with each other at base. At the inner side of epandrium, often if not always, two additional projections with each two spines can be found. Hypandrium long with thin frame, often narrowed at apical part. Hypandrial apodeme often present. Aedeagus hyaline and often extremely elongated and coiled. Basiphallus or basal part of distiphallus normally with long hyaline appendages. Gonites are short and inconspicuous, not fused with aedeagal apodeme but their shape and position resembles the gonites of Agromyza: The thread-like part lies beside the aedeagal apodeme and a wider, flattened outer part is connected with the hypandrium. The tips of gonites are usually located below the epandrium.
Immature stages
Normally more than four mouth hooks on each mandible; left mandible higher than right one but that is hardly visible. The figure Japanag. Larvae.pct shows a selection of typical cephalopharyngeal skeletons.
Posterior spiracles are unique among agromyzids: An external shaft is completely missing. Felt chamber, spiracular glands and ecdysial scars are present but hardly projecting from the surface J parvula Larva SEM.pct. The large felt chamber can show a complex branching pattern and often occupies much space on the last body segment (fig. Sasakawa).
Bionomics
All known species are leaf miners with external pupariation.
Distribution
Japanagromyza species are generally worldwide distributed but missing in Central Europe.