The sharply dividing line between the outer & basal zones indicate a female.
Species in which the division is very sharp includes I. subreducta, paraplesius, hemiphaea, manlia & marapok.
These can be viewed here. https://www.mothsofborneo.com/part-1..._i/gallery.php
I. subreducta can be eliminated as it is cofined to Borneo. I. paraplesius have broad submarginal streaks.
In I. manlia, the FW margin is slightly incurved & the apex slightly falcate (hooked) ; FW submarginal darker, may be spot-like, running in deeper from the apex. https://commons.wikimedia.org/wiki/F...678412544).jpg