Theretra lucasii & latreillii.

T. lucasii was formerly treated as a subspecies of T. latreillii.

T. lucasii is oriental while T. latreillii is Australasian.

T. lucasii. Wings triangular with straight margins, like a jet fighter.
FW with extra submarginal lines beyond the dotted postmedial visible.
https://tpittaway.tripod.com/china/t_luc.htm

T. latreillii.
FW margin more convex & submarginal lines not visible.
http://lepidoptera.butterflyhouse.co...atreillii.html