Key to Cycloneuroterus species

1 Lower face, frons vertex, occiput coriaceous, matt, never shiny; females with inner margins of compound eyes parallel (Figs 56)......................................................................................... fortuitusus

- Lower face alutaceous, only median elevated area delicately coriaceous; frons, vertex, occiput smooth or very delicately alutaceous, shiny; females with inner margins of compound eyes converging ventrally (Figs 1, 18, 36, 72)................... 2

2 Mesoscutellum with parallel sides; females with POL 0.9 times as long as OOL and OOL 3.3 times as long as LOL; males F13 shorter than F12....................................................................................... 3

- Mesoscutellum trapezoid, broadest in posterior 1/4-1/5; females with POL 1.3 times as long as OOL and OOL 1.7 times as long as LOL; males F13 length variable.................................................................... 4

3 Radial cell of forewing short, 3.6-4.0 times as long as broad; mesosoma brown to black; males F1 2.6 times as long as pedicel (Figs 79–80)................................................................................. formosanus

- Radial cell of forewing longer, 5.0 times as long as broad; mesosoma amber; males F1 1.5-1.8 times as long as pedicel (Fig. 25)......................................................................................... longinuxus

4 Radial cell of forewing long, 4.5 times as long as broad; mMesosoma brown to black; males F13 nearly equal F12... lilungi

- Radial cell of forewing shorter, 3.8 times as long as broad; mesosoma amber; males F13 shorter than F12...... lirongchiuea