The Leopard Lacewing (Cethosia cyane) occurs in Asia, from India to southern China.
The female has the same markings as the male but she is much paler.
Where the male is red, the female is more brown-yellow and where the male is black, the female is more greyish.

1st & 2nd photo: A female. Ben Tre area, Mekong Delta, Vietnam, 23 December 2023
3rd & 4th photo: A male. Ben Tre area, Mekong Delta, Vietnam, 22 December 2023
5th photo: Hoi An area, Vietnam, 29 December 2023