Nacaduba berenice?

[Psyche]

It is Prosotas, probably Prosotas nora.

Prosotas (except P. aluta) lacks the costal spot above the cellend bar. ( Sometimes a vestigial dot is present.) Also lowest spot of the FW postdiscal band is usually shifted in ; peripheral spots not marked in white (except P. aluta.).


However there is a very strong suggestion this is Prosotas pia pia.

Typical P. nora have the submarginal & marginal marks or spots equally dark or at least the submarginal spots are darker.Best compare on the HW.
There are very good examples of this species in Singapore.
Males.
http://www.butterflycircle.com/check...imon%20Sng.jpg
https://www.singapore.biodiversity.o...b8b1072e29.jpg
http://www.butterflycircle.com/check...imon%20Sng.jpg
http://www.butterflycircle.com/check...2%20080309.jpg
http://www.butterflycircle.com/check...-Blue---JZ.jpg
https://1.bp.blogspot.com/-GdZarvZ5T...lue-LemonT.jpg

Male India.
https://www.flickr.com/photos/ivijay...n/photostream/
https://www.flickr.com/photos/ivijay...n/photostream/

The female is more orangey. Singapore.
http://1.bp.blogspot.com/_0EK80AsaR7...ine%2BBlue.jpg



Prosotas pia pia. Commoner in the hills in P. Malaysia.
Male upperside more slate blue vs. purple in P. nora male.
Submarginal spots faded out especially on the HW.
Males.
India.
https://www.flickr.com/photos/maanay/37566391576
Thailand
http://4.bp.blogspot.com/-XDY_8ktvVv...+marginata.jpg
https://1.bp.blogspot.com/-Eds5-L78I...-marginata.jpg
Sulawesi.
https://en.wikipedia.org/wiki/Prosot...tiMUpUnAC1.jpg

Brunei. Male P. pia pia.
https://species.wikimedia.org/wiki/P...iaMUpUnAC1.jpg


Females.Thailand.
http://www.samuibutterflies.com/inse...spiamarginata/
https://encrypted-tbn0.gstatic.com/i...0rlMA&usqp=CAU


This male does not look the same as the typical males nora from Singapore.

Furthermore, a mating pair taken years ago in Singapore have the orange female with the HW submarginal spots faded off much as in the female P. pia.
https://farm6.staticflickr.com/5089/...2cf711da_z.jpg



TL Seow: Cheers.
PS. Nacaduba berenice icena males for comparison.
Note FW postdiscal band's lowest spot not shifted in; marginal & submarginal spots strongly defined by white striae ; three costal spots.
https://2.bp.blogspot.com/-ceLml99O5...u/DSC_0187.JPG
http://www.butterflycircle.com/check...obby%20Mun.jpg
http://1.bp.blogspot.com/-xFQx2YUBf8...nice+icena.jpg

Prosotas aluta.
https://2.bp.blogspot.com/-L8WI9UKft...aluta-KSK4.jpg

[Psyche]

It is highly probable that Prosotas pia pia occur in Singapore.


Here is another male from Singapore.
On the HW the dark marginal line angled out in a 'V' at vein 2 (just below the black spot) indicating where the tail is broken off.
The submarginal & marginal spots are much faded.
https://inaturalist-open-data.s3.ama...jpg?1631959024


Both your male & this male have the black markings much reduced, so this is not a one off aberration.
Both are very similar to this male from Brunei.
https://species.wikimedia.org/wiki/P...iaMUpUnAC1.jpg


In contrast P. nora male have the black markings strongly developed giving it a different look.
http://www.butterflycircle.com/check...erry%20Ong.jpg


Probable female Prosotas pia, Singapore.
https://inaturalist-open-data.s3.ama...jpg?1613368451

TL Seow: Cheers.