This study focused on the wing dimorphism of Eobiana engelhardti engelhardti (Uvarov 1926). To examine acoustic differences between macropters and brachypters, we recorded and analyzed the calling songs of the 2 forms. Moreover, the vocal organs of E. e. engelhardti were also observed under optical and scanning electric microscopy. As a result, there were 3 ”dynamic” song traits which had significant differences between the 2 forms, but no obvious differences were observed in vocal organs. For macropters, we assumed that differentiation of these calling songs showed compensation for a reproductive disadvantage. Finally, some molecular biology experiments were conducted to examine differences between the 2 forms at the molecular biology level; as a result, brachypterous insects were grouped in a clade, while macropterous insects were grouped into another, which indicates that these molecular differences had already occurred before these macropters migrated.