E. thrax. FW 31/37 mm.
FW apex sharper & margin straight. UpF apical margin may be lightly shaded white.
Antennal club 1/2 white in female & 2/3 white in male.
HW patch relatively broad throughout.
Previously the continental population was given as E. acroleuca apex.
Taxon apex type location Luzon is now considered as a ssp or full species & is not aplicable to the mainland population (unless the Philippine & continental forms are considered the same.) http://yutaka.it-n.jp/hes/92340010.html
There does not seem to be any article treating taxon apex as a separate species.
See PDF ,A taxonomic note on Erionota acroleuca. https://www.google.com/search?q=erio...hrome&ie=UTF-8
FW sharp ,margin straight. UpF apical margin shaded white but may be brown.
Antennal club fully white above in the male & 1/2 white in the female.
HW with the pale patch much narrower in the upper half.
Smaller FW 29/31 mm.