[[ Exallonyx formicarius-group]]

Key to the Chinese species of formicarius-group ^HNS of Exallonyx ^HNS

1. Flagellum with tyloids......................................................... E. laevigatus Fan and He ^HNS

- Flagellum without tyloids..........................................................................................2

2(1). Abdominal petiole contracted at base........................................................................3

- Abdominal petiole not contracted at base..................................................................4

3(2). Second flagellar segment 2.7× as long as wide; abdominal petiole 1.0× as long as deep in lateral view with six diagonal longitudinal ridges.............. E. strictus ^HNS sp. nov.

- Second flagellar segment 3.4× as long as wide; abdominal petiole 2.0× as long as deep in lateral view with four diagonal longitudinal ridges....... E. pingbianensis ^HNS sp. nov.

4(2). First thyridium 1.8-2.0× as wide as long...................................................................5

- First thyridium 2.5-3.5× as wide as long...................................................................6

5(4). Clypeus 3.1× as wide as long; median groove on syntergite reaching 0.5 to space between tyridia, with two lateral grooves 0.67× as long as median groove ............... .............................................................................................. E. ejunicidus He and Fan ^HNS

- Clypeus 2.5× as wide as long; median groove on syntergite reaching 0.7 to space between thyridia, with two lateral grooves 0.2× as long as median groove................ ............................................................................................. E. fujianensis Fan and He ^HNS

6(4). First thyridium 2.5× as wide as long........................... E. chiuae Townes and Townes ^HNS

- First thyridium 3.1-3.5× as wide as long...................................................................7

7(6). Upper margin of pronotum with 2 rows of setae .................... E. fuliginis He and Fan ^HNS

- Upper margin of pronotum with single row of setae ......... E. nigricornis He and Fan ^HNS