1	Notopleuron and postpronotum light yellow to whitish. Apices of femora all distinctly light yellow. Right sclerite of hypophallus, if present, small and dark. Distiphallus as long as mesophallus, very shallowly curved (Figs 527, 528)	C.magnicornis (Loew)
–	Notopleuron and postpronotum brown, sometimes with yellowish tint and/or small yellow spots in posterolateral corners, but never broadly and distinctly pale as above. Apices of mid and hind femora usually much darker than fore femur (some C.morosa with apices of all femora equally pale). Right sclerite of hypophallus faint to absent. Distiphallus longer, more strongly curved	2
2	Abdomen dark brown with tergites 1–4(5) light yellow excluding faded medial spot. Mesophallus with stem strongly swollen medially. Mesophallus stout, stem strongly swollen medially. Paraphallus well-sclerotised, pointed ventrally. Distiphallus not much longer than mesophallus; basal curve nearly as long as distal; tubules diverging on distal 1/2 (Figs 523, 524)	C.maclayi Spencer
–	Abdomen entirely dark brown. Paraphallus clear, lobate, at most with faint patch of pigment. Mesophallus longer and thinner than above. Distiphallus longer than above, basal curve much shorter than distal curve; tubules parallel along length	3
3	Fronto-orbital plate dirty yellowish brown, contrasting rest of body. Apices of mid and hind femora darker than apex of fore femur. Surstylus with three stout tubercle-like setae. Distal curve of distiphallus ca. as long as mesophallus, semi-circular, slightly swollen apically (Figs 517, 518). Left sclerite of basiphallus small, clavate	C.fasciata (Strobl)
–	Fronto-orbital plate brown to dark brown, not paler than centre of frons (Fig. 105). Apices of femora either dark, as above, or all equally pale. Surstylus with two rows of slender tubercle-like setae. Distal curve of distiphallus very large, slightly straightened medially, not swollen apically (Figs 533, 534). Left sclerite of basiphallus large, pointed	C.morosa (Meigen)