Dr Seow, Aaron, I believe I've shot the males of all our six-line Nacaduba species over the weekend. Are these IDs valid?
1) Nacaduba beroe
Upperside: no white scaling, does not appear powdery.
2) Nacaduba berenice
Upperside, as visible in the first shot as well, powdery blue with white scaling visible.
3) Nacaduba calauria
Upperside: visibly darker than the other Nacaduba species flying around (presumably all N. berenice)