Normally in the past I would consider this a typical female Pantoporia hordonia.
But over the years I have not seen anyone shot a male Pantoporia hordonia.
The last male seem to be this pic of yours.
https://1.bp.blogspot.com/-eHnx5jNOl...ascar-KSK5.jpg
Compare male hordonia from P. Malaysia.
https://inaturalist-open-data.s3.ama...8206/large.jpg
http://4.bp.blogspot.com/-6TIVtGI_ok...0/DSC_0229.JPG
https://inaturalist-open-data.s3.ama...070/large.jpeg
Also female hordonia from P. Malaysia.
The FW orange submarginal band fades off at the apex or is itself rather obscure.
https://inaturalist-open-data.s3.ama...5450/large.JPG
https://2.bp.blogspot.com/-UsULpFSI_...0/DSC_2572.JPG
https://inaturalist-open-data.s3.ama...4148/large.jpg
Other similar pix taken in inaturalist are all females.
https://static.inaturalist.org/photo...636/large.jpeg
https://static.inaturalist.org/photo...381/large.jpeg
https://inaturalist-open-data.s3.ama...6740/large.jpg
Without a single shot of a male hordonia over the years, all these have to be female sandaka.
TL Seow: Cheers.
PS.
Shots of the male P. sandaka from inaturalist are many.
https://inaturalist-open-data.s3.ama...423/large.jpeg
https://inaturalist-open-data.s3.ama...0835/large.jpg
https://inaturalist-open-data.s3.ama...7414/large.jpg