Key to species of Selangomonus gen. nov.

Selangomonus indicus, of uncertain identity (from Myanmar), is omitted from the key and replaced with tentatively identified specimens from elsewhere in Asia. See Remarks under Selangomonus indicus and S. indicus (?) for explanation.

1. Apex of aedeagal shaft compressed and broad in lateral view (Fig. 9G) ......................................... 2

– Apex of aedeagal shaft evenly tapered to acute apex in lateral view (Fig. 5H) ............................... 3

2. Aedeagal shaft abruptly tapered subapically in ventral view (Fig. 4A) (China) ................................ ..................................................................................... S. flataedeagus (Li, 2011) gen. et comb. nov.

– Aedeagal shaft gradually tapered to apex in ventral view (Fig. 9H) (Asia) ....................................... ................................................................................. S. indicus (?) (Distant, 1908) gen. et comb. nov.

3. Aedeagus with preatrium very short about ⅛ length of shaft (Fig. 11H) (China, Thailand) .............. ........................................................................... S. splinterus (Li & Wang, 2005) gen. et comb. nov.

– Aedeagus with preatrium long, ⅓ to ½ length of shaft (Fig. 8G) ..................................................... 4

4. Aedeagal shaft sinuate distally (Fig. 12F) ............................................. S. undulatus gen. et sp. nov.

– Aedeagal shaft evenly curved distally .............................................................................................. 5

5. Pygofer with caudal process; style apophysis longer than rest of style; aedeagus with apex bifid (Fig. 4D) (China) .................................................. S. furcatus (Xing & Li, 2013) gen. et comb. nov.

– Pygofer without caudal process; style apophysis moderately long, length much less than rest of style ................................................................................................................................................... 6

6. Subgenital plate approximately 4 times as long as basal width (Fig. 5K) ........................................ 7

– Subgenital plate less than 4 times as long as basal width ................................................................. 8

7. Anal tube not exceeding pygofer caudal margin (Fig. 8I); aedeagal shaft strongly bent dorsally at midlength (Fig. 8G) (Peninsular Malaysia) .............................................. S. falcatus gen. et sp. nov.

– Anal tube exceeding pygofer caudal margin (Fig. 5J); aedeagal shaft weakly bent dorsally at about distal one-third (Fig. 5G) (Brunei) ...................................................... S. bruneiensis gen. et sp. nov.

8. Aedeagal shaft filamentous, sinuate distally in lateral view (Fig. 4F) (China) .................................. ........................................................................ S. longistyleus (Li & Wang, 2005) gen. et comb. nov.

– Aedeagal shaft robust, evenly curved distally in lateral view (Fig. 4G) (Korea) ............................... ........................................... S. naejangsanus (Dutta, Kwon, Suh & Kwon, 2020) gen. et comb. nov.