Is this a Ionolyce helicon or a Nacduba?

It is a male Nacaduna berenice icena.
There is a costal spot above the innermost FW band.

Both Ionolyce helicon & Nacaduba beroe lacks this costal spot.

I. helicon.
male.
https://static.inaturalist.org/photo.../original.jpeg
females.
http://3.bp.blogspot.com/-_tCoAYTboN...e+(female).jpg
https://i153.photobucket.com/albums/...s/IMG_8894.jpg

N beroe.
Male above, female below.
https://inaturalist-open-data.s3.ama...4/original.jpg
Female.
https://static.inaturalist.org/photo.../original.jpeg

N. berenice icena.
Almost always have a costal spot above the innermost FW band.
FW band may also looks like I. helicon.
Males.
https://farm4.staticflickr.com/3225/...5c1_z.jpg?zz=1
http://www.butterflycircle.com/check...hee%20Beng.jpg
Females.
https://i22.photobucket.com/albums/b...a/nacuduba.jpg
http://www.butterflycircle.com/check..._female_01.jpg

TL Seow: Cheers.