Sobarocephala, Czerny, 1903

Lonsdale, Owen & Marshall, Stephen A., 2012, 3370, Zootaxa 3370, pp. 1-307 : 17-18

Key to the Species Groups of Sobarocephala .

1. Frons narrowing towards back of head (Fig. 23). M 1+2 ratio greater than 2.0 and wing usually only infuscated along anterodistal margin; if wing elaborately patterned, then without spot immediately after costal cell. Rectal papillae without minute comblike structures on outer surface (Fig. 47). Usually with either i) ivory-white notopleuron (Fig. 20), or with ii) densely plumose arista (entirely dense, never just at base) (Fig. 23), minute ocellar bristles AND bulging face. New World and (rarely) East Asia................................................................................ S. flaviseta species group

-- Frons usually parallel-sided (Fig. 24); if frons slightly narrowing posteriorly (some S. ruebsaameni group; Fig. 25), then wing elaborately patterned ( Figs 31–39) and M 1+2 ratio less than 2.0. Rectal papillae with minute comb-like structures on outer surface (Figs 48a–c). Notopleuron never white and arista usually sparsely plumose (Fig. 24); if hairs on arista densely plumose (usually only at base), then face flat and ocellar bristles long.................................................... 2

2..First flagellomere with dorsal stripe, arista densely plumose at base, AND paraphallus with thumb short and broad or entirely absent. Old World..................................................................... S. plumicornis group

-- Never with above combination of all three characters, although one or two sometimes present. New World and (rarely) Old World.............................................................................................. 3

3. Wing strongly patterned ( Figs 31–39), usually with dark spot as long as costal cell on costa immediately after cell. M 1+2 ratio usually less than 2.0. Surstylus thickened posterobasally, making it appear bifid when viewed posteriorly (Fig. 256). Abdominal pattern often divided medially (Figs 58–60). Tropical Neotropics........................... S. ruebsaameni group

-- Wing usually clear or with anterodistal infuscation, but if spotted, never with dark spot on costa immediately after costal cell. M 1+2 ratio always greater than 2.0 (often more that 3.0). Surstylus sometimes bifid ( Fig. 378), but never due to posterobasal swelling. Abdominal pattern never divided medially........................................................... 4 4. Scutellum laterally or entirely yellow. Female abdomen sometimes with medial stripe on tergites 2–4 and with tergites 5–7 very dark. Surstylus with several scattered nub-like bristles along outer-posterior margin (Fig. 193) and usually much larger than epandrium (except in S. lobillis and S. pengellyi ). All hypandrial bristles small to minute (Fig. 194). North America, Japan and Costa Rica............................................................................. S. flava group

-- Scutellum variously coloured (sometimes entirely yellow). Female abdomen never as above. Surstylus variable in shape, with small nub-like bristles absent or only present on inner face. At least one pronounced hypandrial bristle present. North America and tropical Neotropics................................................................................. 5

5. Tubercle-like bristles along length of distal and posterior margins of surstylus on inner surface (bristles on inner face sometimes modified into long spines). Male cerci small and rounded ( Fig. 226)......................................... 6

-- Tubercle-like bristles (if present) small, rounded and restricted to apex of surstylus (scattered posteromedial nub-like bristles secondarily recovered in a few species with a distinct posteromedial comb of bristles on the 5 th sternite). Male cerci usually flat, concave or distinctly projecting past distal margin of epandrium............................................. 7

6. Frons and legs often brown, at least in part. Scutum usually dark with one pair of yellow stripes that usually converge anteriorly ( Figs 96, 99, 104). Male wing sometimes widened with R 2+3 bent distally and costa with spines ( Fig. 42). Surstylus with small tubercle-like bristles ( Fig. 226). Neotropical Region....................................... S. latipennis group

-- Frons and legs yellow, sometimes with fore tibia and tarsi brown. Scutum yellow with one or two medial stripes. Male wing never as above (usually as in Fig. 41). Surstylus only with long stout spines on inner face (Fig. 181). Neotropical Region................................................................................. S. archisobarocephala group

7. Male cerci shallow, flat or concave with setae all short (Figs 352, 364, 370). Male often either with i) bifid surstylus ( Fig. 378), or ii) discrete patch(es) of bristles on 5th sternite ( Figs 176–178) and no tubercle-like bristles on surstylus. Nearctic and Neotropical Regions....................................................................... S. interrupta group

-- Male cerci projecting with one pair of longer apical bristles ( Fig. 262). Male 5 th sternite evenly and sparsely setose ( Fig. 179), small rounded bristles always present on surstylus, and surstylus never bifid....................................... 8

8. One pair of lateral scutellar bristles. Ocellar bristles small. Wing width three times length. Epiphallus medial on basiphallus and not angled forwards (Fig. 269). Ecuador.................................................... S. erwini group

-- Usually two pairs of lateral scutellar bristles. Ocellar bristles variable. Wing width less than 2.5 times length ( Fig. 40). Epiphallus distal on basiphallus and usually strongly angled forwards ( Figs 305, 338). Neotropical Region...... S. isla group