18.https://www.inaturalist.org/observations/233627479
Male Horaga syrinx.

Four species have a very similar appearance.
The two larger species H. onyx & syrinx have the fore-tibiae banded black.
The two much smaller spp. H. albimacula & chacedonyx have the fore-tibiae largely white.

H. onyx .
UnF white spot broad with a distinct notch.
HW postdiscal band/line extend across vein 11a to the margin.
https://www.gbif.org/occurrence/2847199899
https://www.gbif.org/occurrence/2847199900
https://www.butterflycircle.com/chec...a_sp_adult.jpg

H. syrinx.
FW spot narrower ,less notched.
HW postdiscal line falls short of crossing vein 1a.
https://www.gbif.org/occurrence/2847199957
https://www.gbif.org/occurrence/2847199929
https://www.butterflycircle.com/chec...20-%20Khew.jpg
https://www.butterflycircle.com/chec...wbutterfly/169

The two small species have the foretibiae partially white.
H. albimacula.
https://www.butterflycircle.com/chec...raga_sp_01.jpg
H. chacedonyx.
https://www.butterflycircle.com/chec...nyx_HTan01.jpg