Key to the species of Nematopus known from French Guiana

1 Antennal segment IV black with yellow ring near basal third; antennal segments II and III black with basal joint yellow; connexivum shiny orange; abdominal sterna III to VII shiny orange; male genital capsule and female genital plates black (Fig. 7). ................... ................................................................................................ N. indus (Linnaeus, 1758)

– Not with this combination of characters. ....................................................................... 2

2 Fore and middle femora shiny reddish brown; hind femur shiny reddish brown to black; humeral angles barely exposed, rounded (Fig. 8). ............... N. nervosus Laporte, 1832

– Fore and middle femora yellow with pale green sheen; hind femur yellow with pale green sheen, and with or without posterior third brown; humeral angles conspicuosly expanded into medium size spine directed outward, and clearly upward, (Fig. 9). .......... ....................................................................................................... N. persuasus sp. nov.