Key to the species of Pyrops in Thailand (adapted from Constant & Pham, 2022)

1. Apex of cephalic process not inflated (Figs 1, 3–13).......................................................... 3

–. Apex of cephalic process strongly inflated (Figs 2, 14A)..................................................... 2

2. Abdomen black ventrally; cephalic process bright yellow; tegmina pale yellow and black with three black spots on costal area before nodal line (Fig. 14; see also Constant & Pham, 2022: Fig. 1B)....................... P. atroalbus (Distant, 1918)

–. Abdomen red ventrally; cephalic process dark brown or black; tegmina with black or pale blue marking on disc (Fig. 2)................................................................................. P. clavatus (Westwood, 1839)

3. Cephalic process entirely green; posterior wings always yellow or orange basally.................................. 4

–. Cephalic process not green; posterior wing yellow, blue or white............................................... 5

4. Tegmina bright green with small yellow spots, posterior wings entirely yellow or orange; anterior and median legs green (Fig. 6B)........................................................................... P. itoi (Satô & Nagai, 1994)

–. Tegmina black with green vein, posterior wings yellow basally with apical third black; anterior and median legs largely black or brown-black (Fig. 13B).................................................... P. viridirostris (Westwood, 1848)

5. Cephalic process black, pale brown or brown-black dorsally (Figs 8D, 11D)...................................... 6

–. Cephalic process red, yellow-red or red-brown dorsally, yellow to dark red ventrally (Figs 1D–E, 5D–E).............. 11

6. Colour of the apex of the cephalic process strongly contrasts with the rest of the process (Fig. 11C–D)................. 7

–. Apex of cephalic process coloured like the rest of the process (Fig. 1C–D)........................................ 8

7. Cephalic process slender and slightly curved, yellowish orange at the apex of process; posterior wings bright yellow (Fig. 8) or milky white (see also Constant & Pham: Fig. 7).......................................... P. lathburii (Kirby, 1818)

–. Cephalic process robust, slightly straightforward, red at the apex of process; posterior wings bright blue, distal portion black extending along the posterior margin (Fig. 11).................................... P. pyrorhynchus (Donovan, 1800)

8. Femora brownish orange or orange (Figs 3B, 12B)........................................................... 9

–. Femora dark brown to black (Figs 4B, 10B)............................................................... 10

9. Tegmina narrower: LTg/BTg> 2.9; spots on basal half of tegmina not fused into bands; cephalic process narrower (LPr/BPrH> 9); posterior wings bright yellow or white basally (Fig. 3).......................... P. condorinus (Lallemand, 1960)

–. Tegmina broader: LTg/BTg <2.9; spots on basal half of tegmina fused into transverse bands; cephalic process broader (LPr/ BPrH <9); posterior wings always bright yellow basally (Fig. 12)....................... P. spinolae (Westwood, 1842)

10. Large size: TL+process = 70.1–72 mm; cephalic process long and strongly curved; tegmina with large yellow spots form as transverse bands on basal half; posterior wings pale blue basally (Fig. 4)................ P. connectens (Atkinson, 1885)

–. Small size: TL+process = 33–33.7 mm; cephalic process short and moderately curved; tegmina with small orange spots; posterior wings can be from yellow to nearly red basally (Fig. 10)............................ P. peguensis (Schmidt, 1911)

11. Tegmina without yellow spots in distal third; cephalic process dark red, orange ventrally and at apex; posterior wings pale blue to white basally; basal half of tegmina whitish with white-margined green spots in transverse rows, sometimes fused in bands (Fig. 5)............................................................................ P. ducalis (Stål, 1863)

–. Tegmina with yellow spots in distal third; cephalic process red or red-brown..................................... 12

12. Hind wings largely white basally; tegmina olive green with small yellowish brown spots circled with white (“ocelli”), forming transverse rows on basal half; cephalic process brownish red dorsally, yellow ventrally (Fig. 9).................................................................................................... P. oculatus (Westwood, 1838)

–. Hind wings blue or bright yellow basally; tegmina with large yellow markings on basal half; cephalic process bright red to yellowish red......................................................................................... 13

13. Hind wings bright yellow basally; tegmina with green veins and veinlets, sometimes yellow markings on the basal half form as X shape; cephalic process bright red (Fig. 1)....................................... P. candelaria (Linnaeus, 1758)

–. Hind wings blue basally; tegmina with yellowish brown veinlets on the membrane, yellow markings on basal half forming transverse, parallel rows; cephalic process red (Fig. 7)................................... P. karenius (Distant, 1891)