I think Ian got it right. The main fw transverse mark goes right across from the costa to the inner margin, even being strongest at the inner margin, on E. postvittana (for one of the main pattern variations), whereas on M. laganodes it spreads out and stops part way across from the costa. Also, only (some of) E. postvittana has the double dark spots on the thorax and the dark marks towards the base of the inner margin of the fw that form the prominent single dot in a settled moth. The different colour forms of E. postvittanan are very different.