Key to species of Chinese Ptecticus (partly based on Rozkošný & Hauser, 2009)
1 Median occipital (post vertical) sclerite yellow............................................................... 2
- Median occipital sclerite black........................................................................... 7
2 Wing bicoloured or more or less darkened.................................................................. 3
- Wing hyaline......................................................................................... 5
3 Male cerci slender, gonostyli shifted to middle, slender and narrow............................... P. kerteszi de Meijere
- Male cerci broad, nearly triangular, gonostyli broader and in normal position...................................... 4
4 Darkening of wing apex reaching discal cell or nearly so; basal 1–4 abdominal segments usually ochre yellow, rest of abdomen wholly black........................................................................ P. melanurus (Walker)
- Darkening of wing apex reaching usually only middle or slightly more of distance between discal cell and wing margin; abdominal segments 3–5 usually with extensive dark spots...................................... P. aurifer (Walker)
5 Legs mostly black, tarsi yellowish brown, but basitarsus of hind tarsus black with yellowish brown apex...................................................................................................... P. brunescens Ôuchi
- Legs predominantly yellow.............................................................................. 6
6 Legs mostly yellow, but hind tibia black, hind tarsus white but basitarsus with black base; aedeagal complex thick............................................................................................ P. sinchangensis Ôuchi
- Legs mostly yellow, but tarsomeres 4 and 5th tarsomeres of fore and mid legs black; aedeagal complex slender with pointed apex............................................................................. .. P. elongates Yang et al.
7 R2+3 very short, mostly indistinct.......................................................... P. shirakii Nagatomi
- R2+3 long, distinctly visible............................................................................... 8
8 Hind legs completely black; male cerci unusually long...................................... P. japonicus (Thunberg)
- Hind legs at least partly yellow; male cerci not unusually long.................................................. 9
9 Postcubitus vein distinct............................................................................... 10
- Postcubitus vein not pigmented......................................................................... 12
10 Scutum mostly black or at least partly black................................................................ 11
- Scutum wholly brownish yellow; abdomen brownish yellow with black transverse spots.............. P. cingulatus Loew
11 Scutum with 3 broad black strips............................................................. P. tricolor Wulp
- Scutum wholly black................................................................... P. bicolor Yang et al.
12 Scutellum dark to black with yellow to brown margin........................................................ 13
- Scutellum yellow to brownish yellow.....................................................................15
13 Pleura wholly pale yellow, without any spots; hind basitarsus snow white but its outer side with black basal part.............................................................................................. P. brevispinus sp. nov.
- Pleura yellow, with large brownish to bluish-black spots; hind basitarsus snow white, darkened at most basally.......... 14
14 Genital capsule without posterolateral proceses................................... P. longispinus Rozkošný & Kovac
- Genital capsule with long posterolateral process on each side............................. P. longipennis (Wiedemann)
15 Lower half of frontal callus markedly darkened............................................ P. vulpianus (Enderlein)
- Frontal callus wholly yellow............................................................................ 16
16 Aedeagal complex reduced, ring-shaped proximally.......................................... .. P. australis Schiner
- Aedeagal complex of another shape...................................................................... 17
17 Genital capsule with broad bipartite medial process distally, gonostylus slender (Rozkošný & Hauser, 2001: Figs 6–7)................................................................................ .. P. srilankai Rozkošný & Hauser
- Medial process of genital capsule consisting of two slender structures, gonostylus stout, abruptly tapered before apical tip....................................................................................................... 18
18 Genital capsule transverse, broader than long, aedeagal complex only little sclerotised, flat, short and bifid apically, not swol- len proximally (Rozkošný & Hauser, 2009: Figs 9, 10)............................. P. fukienensis Rozkošný & Hauser
- Genital capsule longer than wide, aedeagal complex well sclerotised, bipartite and both parts gradually tapered and pointed apically, base of aedeagal complex swollen, almost round (Figs 10–12)......................... P. guangxiensis sp.nov.