Diagnosis of the Orphninae (based on the adult characters)
Mandibles with 2-4 scissorial teeth and a well developed mola; labrum and mandibles protruding past the clypeus and can be seen from above (except for South American Onorius, which has mandibles feebly or not visible from above).
Antennae 10-segmented with a 3-segmented club.
Scutellum well developed in winged species, reduced but distinct in wingless species.
Wings with a distinct anal area.
Apex of the anterior tibia in males without a spur but normally with a few robust setae.
Anterior coxa with a longitudinal hollow on the anterior surface.
Tarsi of all legs with 2 similar claws.
Middle and hind tibiae with 2 apical spurs.
Second abdominal sternite with a sub-triangular to rounded plectrum on each side.
Dorsal surface of hind coxae with a flat stridulatory file basally.
Parameres symmetrical (except for a few species of Aegidinus).
Bursa copulatrix sacciform, membranous. Accessory vaginal glands developed.
Spermatheca C-shaped, not sclerotized.
Abdomen with 2 sclerotized tergites (VII-VIII) and 6 sternites visible in situ (III-VIII).
Males of most species may have clypeal horn and prothoracic ridges.