This is O. indistincta.
I have been discussing this issue with Martin Honey at The Natural History Museum, London, as part of the preparatory work for the Moths of HK book. Moths of Thailand is incorrect: plate 19 no. 3 is an unidentified Ophiusa, 4 & 5 are O. triphaenoides and 6 is O. indistincta. Ophiusa indistincta is much redder than the others and has a much darker suffused basal half of the hindwing. Ophiusa olista has not been recorded from Hong Kong - the f/w subterminal fascia is distinct, being much more "wavy" than in the congeners that occur in HK.