Key to the species of Naucoridae of China

1. Apex of head folded under and backward, such that the rostrum arises at a point posterior to the anterior margin of the head when viewed laterally or ventrally........................................................................ 2

- Apex of of head not folded under and backward, rostrum arising at anterior margin of head when viewed laterally.................................................................................................... Naucorinae 7

2. Rostrum recessed into a cavity on the underside of the head................................. Cheirochelinae ...... 3

- Rostrum not recessed into a cavity, pointing backward but flush with the underside of the head........ Laccocorinae ..... 8

3. Abdomen longer than wide.............................................................................. 4

- Abdomen wider than long............................................................................... 6

4. Brachypterous forms; forewings membrane degenerated....................................................... 5

- Macropterous forms; forewings membrane fully developed (Fig. 2); parameres elongate, slightly thicker and weakly bifurcate basally, bearing fringe of long setae on outer margins, apices notched to varying degree.. Cheirochela tonkina Polhemus et al.

5. Lateral margin of pronotum strongly concave, forefemur wide and flat (Fig. 1).................... Ch. feana Montandon

- Lateral margin of pronotum slightly concave, forefemur ventral stout (Figs. 3, 4).................... Ch. grossa sp. nov.

6. Brachypterous forms; posterolateral angles of pronotum acute (Figs. 5, 6)........... Gestroiella limnocoroides Montandon

- Macropterous forms; posterolateral angles of pronotum right angle (Figs. 7, 8)............... G. limnocoroides Montandon

7. Body length less than 10 mm; pronotum brown, surface with black spot (Fig.13), parameres asymmetrical.............................................................................................. Thurselinus scutellaris (Stål)

- Body length exceeding 10 mm; pronotum yellowish, surface without black spot (Fig. 18), parameres symmetric............................................................................. Ilyocoris cimicoides cimicoides (Linnaeus)

8. Metaxyphus without acuminate tip........................................................................ 9

- Metaxyphus with acuminate tip..................................................... Ctenipocoris sinicus Zettel

9. Body length less than 9.5 mm........................................................................... 10

- Body length exceeding 10.0 mm......................................................................... 11

10. Head and pronotum almost entirely yellow, without brown maculation......................... Heleocoris jaechi Zettel

- Head and pronotum yellow with obvious brown maculation (Fig. 17)............... H. bengalensis montandoni Lundblad

11. Male left paratergite VI bearing a blunt process laterally; forewings and scutellum black (Figs. 14, 15). H. ovatus Montandon

- Male left paratergite VI lacking a process laterally; forewings and scutellum brown (Figs. 9, 10)..................... 12

12. Posterolateral corner of pronotum arc-shaped............................................ H. breviceps Montandon

- Posterolateral corner of pronotum obtusely angled (Figs. 11, 12)............................... H. strabus Montandon