Acherontia styx (Westwood, 1847)

Individually variable in colour and pattern. Antenna much more slender and obviously longer than in similar-sized Acherontia atropos, the middle segments in the female barely 3x as broad as long. Thorax upperside with skull-like mark narrower than in Acherontia atropos, not constricted in the middle; often black with a pale ochraceous edge, sometimes ochraceous tawny, more uniform in colour than in Acherontia atropos or Acherontia lachesis. Mesothoracic tegula wider anteriorly than in Acherontia atropos, causing the narrowing of the skull-like mark, and not broadened posteriorly. Metanotum always with a bluish white line. Abdomen upperside with tergites having apical bands usually, but not always, more or less dilated laterally, sometimes touching each other at least on proximal segments. Abdomen underside with black marks restricted to small mesial basal spots, not with the broad basal bands of Acherontia atropos. Anterior tibia longer and with fewer spines than in Acherontia atropos, marked with yellow buff, the tarsi ringed with buff, not white as in Acherontia atropos. Midtibia as long as 1st tarsal segment. Hindtibia equal in length to the first 3 tarsal segments together. Forewing upperside subbasal line less curved distad in the cell than in Acherontia atropos; white or buffish basal and discal spaces between the black dentate lines generally less pronounced than in Acherontia atropos; discal spot buffish; degree of tawny russet scaling variable. Forewing underside usually with a blackish cloud in the discal cell along the cubital vein proximal to the middle; discal third of the wing usually with much black scaling; 2 discal bands usually present and the trace of a third, the 1st variable in position, sometimes close to the discal cell, the 2nd often indistinct or occasionally absent. Hindwing upperside differs from Acherontia lachesis in having the basal half entirely yellow, as in Acherontia atropos, lacking a large black mark; discal black band generally more proximal and straighter than in Acherontia atropos, reduced in width and length in many individuals; distal black band usually more deeply incised between the veins on the proximal edge, often separated into vein-streaks connected by diffuse black scaling. Hindwing underside with discal spot occasionally obliterated; in some individuals it is touched by the discal band.

Male genitalia: Harpe with ventral process almost vertical on the plane of the valve, its broader side nearly horizontal; the 2nd process triangular, as in Acherontia atropos, its broader side dorso-ventral (vertical); both processes simple or indistinctly notched.

Female genitalia: Ostium bursae without process, but with a mesial carina running proximad from the rim of the opening.