Key to species (males) of Scaphomonus

1. Aedeagus with pair of spine-like apical processes (Fig. 2E–F); style with apophysis longer than section of shank based of lateral lobe (Fig. 2G) (Sarawak, Sabah) .................. S. bispinosus sp. nov.

– Aedeagus without pair of spine-like apical processes; style with apophysis shorter than section of shank based of lateral lobe ................................................................................................................ 2

2. Aedeagus with very long and narrow apically bifid shaft (Fig. 1A); basal apodeme long (Fig. 1B) (India) ............................................................................. S. arcuatus (Viraktamath & Mohan, 1993)

– Aedeagus with shaft and basal apodeme short to long; apex of shaft not bifid ................................ 3

3. Aedeagus with shaft long, curved posteriorly; basal apodeme longer than half length of shaft (Fig. 1D) ........................................................................................... S. vateriae (Viraktamath, 2009)

– Aedeagus with shaft short to moderately long, curved dorsally; basal apodeme half or less that half length of shaft ................................................................................................................................... 4

4. Aedeagal processes directed caudally (Fig. 1E); basal apodeme comprising two diverging basal arms (Fig. 1F) (China) ................................................................................. S. widestyleus (Li, 2011)

– Aedeagal processes directed towards base of aedeagus in lateral view; basal apodeme not comprising two diverging basal arms .................................................................................................................. 5

5. Aedeagus with two pair of apical processes (Fig. 1G–H) (India) ...................................................... .................................................................................... S. quadrifidus (Viraktamath & Mohan, 1993)

– Aedeagus with a single pair of apical processes ............................................................................... 6

6. Pygofer with caudal process absent; connective with stem much longer than arms (India) .............. ........................................................................................... S. freytagi (Viraktamath & Mohan, 1993)

– Pygofer with caudal process present; connective stem shorter to slightly longer than arms ............ 7

7. Pygofer process strongly curved dorsally; connective stem slightly longer than arms (India) .......... .............................................................................................................. S. redundans (Distant, 1918)

– Pygofer process not strongly curved dorsally; connective stem shorter than arms .......................... 8

8. Base of aedeagus broad in lateral (Fig. 1N), processes broad in ventral view (Fig. 1D) (India) ........................................................................ S. malnadicus (Viraktamath & Mohan, 1993)

– Base of aedeagus narrow in lateral view (Fig. 1P), processes narrow in posterior view (Fig. 1O) (India) ........................................................................ S. agumbensis (Viraktamath & Mohan, 1993)