Quite right. Both males.

Caltoris cormasa .generally redder brown than all other Caltoris.
Male have a greater contrast between FW & HW. The FW being lighter. Pix colour variable.
Two males , two females.
http://4.bp.blogspot.com/-b-kBsIeG7M...altoris-sp.jpg
http://2.bp.blogspot.com/-TjKxWVHrQm...herHern_01.jpg
http://3.bp.blogspot.com/-dg1jseJPJ2...0/DSC_0115.JPG
http://www.natureloveyou.sg/Minibeas...318%20(10).JPG

Potanthus serina. Large species with sharper FWs.
1. FW spot 5 1/2 of spot 4.
2. HW spot6 small at upper inner corner of band.
3 Marginal areas neat with veins dark-dusted.
http://www.butterflycircle.com/check...serina-KSK.jpg

TL Seow : Cheers.