The present taxon is characterized here for the first time. In erecting this new taxon, I will be able to describe the large amount of characters shared by each genus within this taxon and to avoid unnecessary repetitions. I hope the classification of Agromyzidae will become more comprehensible.
The Ophiomyiini constitutes a clearly monophyletic group containing the genera Ophiomyia, Hexomyza, Tropicomyia, Kleinschmidtimyia and Melanagromyza. Their sister group certainly is the genus Japanagromyza. It can be characterized by many apomorphies in both adults and immature stages.
Among these are the strange shape of the distiphallus, the gonites, the divided puparial cap and some characters of the cephalopharyngeal skeleton. Further details and illustrations are given below.
Adults, external
Halteres entirely black, body either greenish or bluish shining or not.
The adults are similar to the related genus Japanagromyza. They share the following characters: Ocellar triangle large and well separated from frons, body surface black, often bluish or greenish shining. Only two pairs of dorsocentral bristles present on mesonotum.
Unlike Japanagromyza and Agromyza the halteres are always black.
Male genitalia
Epandrium short in lateral view, surstyli not articulated, situated at the lower part of epandrium. The insides of the two epandrium-apices are long and broad, fused with each other near the base of cerci.
Gonites reduced, not closely connected with the aedeagus as in Agromyza. Apical parts of gonites developed as inner layers within epandrium (Oph pinguis hypandrium.pct).
Hypandrium mainly with broad frame and frequently with conspicuous hypandrial apodeme.
In ventral view of the male postabdomen, the whole aedeagus somewhat directed to the right side (Hex simplex genitalia.pct). Basiphallus often weakly sclerotized; bridge between lateral sclerites of basiphallus present, often in oblique position to the side sclerites. In many cases the bridge and some apical vestiges of the side sclerites are the only visible parts of the basiphallus.
Distiphallus shows a complex unique shape never found in other agromyzids. Some structures are not yet fully understood. Basal vesica usually small, terminal tubules bifid, apically normally very tiny. Next to the small basal vesica an additional pair of vesicae (subbasal vesicae) are situated (Tr flacourtiae genitalia.pct, Mel sojae aedeagus.pct). Their position is on the ventral side of the aedeagus. That means that in retracted position of the male genitalia, the subbasal vesicae are between the basal vesica and the abdominal tergites. Since they are arranged in a pair, they are certainly derived from parts of the terminal tubules of the distiphallus.
However, in certain cases the general shape can be considerably different and not easy to understand. In many Ophiomyia and Tropicomyia the subbasal vesicae are in distinctly more apical position than the basal vesica whereas in most Melanagromyza both kinds of vesica nearly completely overlap.
The visible structures of the distiphallus are often covered with a translucent membrane especially in Melanagromyza.
Immature stages
Within this taxon the upper puparial cap is further divided by a preformed longitudinal suture puparia Tropicomyia/phytomy.pct. Most probably, the additional slit improves the ability of the emerging adult to escape from the puparium which is always happening within the host plant.
The dorsal bridge of the larval cephalopharyngeal skeleton is either strongly reduced or missing. Compare a species not belonging to Ophiomyiini (e.g. agrom ceph aabiens.pct Japanag. Larvae.pct), and OphiomyiiniOphiomyia gr. ceph.pct.
Bionomics
Within this genus all major feeding habits from leaf and stem mining to gall inducing occur. The fully-grown larvae pupate within the mine or gall, normally just below the surface.