Diagnosis. M 1 distally abbreviated, not reaching wing margin (Fig. 3 A, 3 D, 3 G, 3 J).
Description. Male and female: Eyes red to brownish red. Ocellar triangle dark brown to black, with a pair of setae above ocellar setae. Postocellar seta usually small. Frons brown, narrow, nearly parallel, with a few minute setulae medially. All orbital setae large; proclinate and anterior reclinate orbital setae very close together, separated by distance less than 1 / 2 of that between anterior reclinate and posterior reclinate. Pedicel yellow; first flagellomere brownish; arista long plumose. Face mostly yellow; facial carina undeveloped. Clypeus yellow. Palpus brownish yellow, slender in both sexes. Vibrissa prominent; other orals small. Gena and postgena narrow. Mesonotum yellow to brown, not pollinose. Postpronotal lobe with 2–4 long setae and a few of shorter setae. Acrostichal setulae in ca. 12–14 irregular rows. Prescutellar setae large. Katepisternum yellowish, with small setae medially, and 2 large ones anteriorly and posteriorly, respectively. Subscutellum swollen. Basal medial-cubital crossvein absent. Wing costal vein between R 2 + 3 and R 4 + 5 distally with more than 5, 6 peg-like spinules on ventral surface; R 2 + 3 sometimes curved to costa at tip. Halter mostly yellowish white. Legs mostly yellowish. Abdominal tergites variable in the color and pattern. Male terminalia: Epandrium usually with sparse pubescence and several setae around posterodorsal to ventral margins; apodeme usually developed (Figs 5–8 A). Surstylus broad, flat, nearly entirely pubescent, with several setae on outer and inner surface (Figs 5–8 A). Cercus separated from epandrium, with several setae, lacking pubescence (Figs 5–8 A). Hypandrium (gonopod in Bächli et al. 2004) anteriorly fused to aedeagal apodeme, laterally broad, usually with paramedian setae subbasally. Gonopods (dorsal arch in Bächli et al. 2004) fused with each other, forming slightly triangular plate, anterioventrally with curved, median rod. Paramere (outer paraphysis in Bächli et al. 2004) contiguous to arm of aedeagal apodeme basally, lacking pubescence (Figs 5–8 B). Aedeagus glabrous (Figs 5–8 C); basal bridges contiguous to median rod of gonopod; apodeme with a pair of arms each contiguous to base of paramere.
In the following descriptions of each species, only characters that depart from the upper universal characters are provided for brevity.