Key to species of the arcuatus -group of Paraclius (males)

1 Antenna wholly dark brown to black (e.g. Figs 1E, 2E, 8E); face gradually narrowing below (funnel-shaped), narrowest point slightly wider than mid ocellus (e.g. Figs 1D, 2C, 7E); clypeus short, about 1/4 as long as face (e.g. Figs 1D, 2C, 8C, 11C); anal lobe barely developed (e.g. Figs 2F, 11F, 8F); tergite 6 either with short or long and strong lateral setae (e.g. Figs 1H, 8D, 9F, 11E); apicoventral epandrial lobe not developed (e.g. Figs 3G, 9E, 12D)................... arcuatus -group of Paraclius 2

- Antenna usually orangish-yellow, with only apical 1/2 to apical 1/3 of postpedicel brown to dark brown; face various, distinctly wider than mid ocellus at narrowest point; clypeus usually 1/2 to 1/3 as long as face; anal lobe normally developed; tergite 6 bare; apicoventral epandrial developed................................................... other Paraclius groups

2 Postpedicel subrectangular, pointed dorsally at apex (Figs 1E, 2E, 11D); femur I wholly yellow (Figs 1A, 2A, 6A, 11A); CuAx ratio: 0.6 or greater (Figs 1I, 2F, 11F)..................................................................... 3

- Postpedicel various, not pointed dorsally at apex (Figs 8E, 15D, F, 19F); femur I mostly brown to dark brown (e.g., Figs 7A, 8A, 14A); CuAx ratio: 0.3–0.5 (e.g., Figs 7A, 8F, 15E)....................................................... 5

3 Scutellum with 1 pair of short apical setae (Fig. 6C); femur II yellow with apical 1/3 to 1/2 brown to dark brown (Figs 2A, 4A, 6A); male tergite 6 bare (Fig. 2D)............... P. arcuatus (Loew) [Widespread in Central America, Cuba and Jamaica]

- Scutellum without pair of apical short setae (Figs 1B, 11B); femur II yellow (Figs 1A, 11A); lateral margins of male tergite 6 with strong setae (Figs 1H, 11E)......................................................................... 4

4 Wing wholly brownish (Fig. 11F); basal apicoventral epandrial seta about 2X longer than apical seta, and both shorter than ventral lobe of surstylus (Fig. 12C, D).................. P. brooksi sp. nov. [Mexico (Chiapas and Oaxaca) and Grenada]

- Wing wholly grayish (Fig. 1I); basal apicoventral epandrial seta as long as apical seta, and both longer than ventral lobe of surstylus (Fig. 1G).............................................................................................. P. angusticauda Van Duzee, 1933 [Guatemala]; P. elongatus Van Duzee, 1930 [Saint Vincent and the Grenadines]

5 IIt 1 wholly dark brown (Figs 7A, 8A); phallus with fringe of spines at apical 1/2, not reaching the apex of phallus (Fig. 9B–D); ventral lobe of surstylus short, gently curved ventrally, about 1/3 as long as basal apicoventral epandrial seta (Fig. 9B, C, H)..................................................... P. angustipennis Van Duzee, 1929 [Guatemala and Mexico]

- IIt 1 yellow on basal 1/2 and brownish on apical 1/2 (Fig. 19A); phallus plain, lacking spines (Figs 16E, 20E); ventral lobe of surstylus long, gently to strongly curved ventrally, about 1/2 as long or slightly shorter than basal apicoventral epandrial seta (Figs 16C–E, 20D).................................................................................... 6

6 Tergite 6 with row of 3–4 strong lateral setae increasing in length towards posterior margin (Fig. 16I); sternite 5 U-shaped anteriorly (Fig. 16A); ventral lobe of surstylus strongly curved ventrally (Fig. 16C–E); dorsal lobe of surstylus weakly sclerotized, short, subrectangular, with 1 slender apicoventral seta, as long as dorsal lobe of surstylus, and 2 strong setae, 1 at apical margin and 1 subapical at dorsal edge (Fig. 16F)............... P. pumilio Loew [Widespread in Mexico and USA]

- Tergite 6 with two rows of 7–8 short lateral setae (Fig. 19E); sternite 5 divided in two narrow hemitergites anteriorly (Fig. 20A); ventral lobe of surstylus gently curved ventrally (Fig. 20C, D); dorsal lobe of surstylus suboval, with dorsal row of short setae at basal 1/2, ending in 1 strong seta at middle and with 1 strong seta at apex (Fig. 20D)........... P. xibun sp. nov. [Belize]