Species: Mahathala ameria burmana (Talbot, 1942)
Common name(s): The Falcate Oakblue
Photography location: Hanoi (Mt Ham Lon)
Monastyrskii & Devyatkin (2016) listed 2 Mahathala species in Vietnam viz. ameria and ariadeva - the former widespread, the latter only recorded in the South (Dong Nai Prov.).
ID credit: Alexander MonastyrskiiNot the best shot in the world but enough for a positive ID. Underwing pattern very similar to that of Arhopala species but note the HW deeply excavated at apex. Photo taken on June 24, 2016