Megacorma
Cannot be confused with any other sphingid; the combination of the labial palp structure, long thorax and wing pattern is unique. Proboscis much longer than body. Labial palp distinctive: segment 2 triangular, much shorter than segment 1; apex of segment 1 with large cavity. Thorax very long, extending far beyond base of forewing. Forecoxa with conspicuous hair pencil. Mid- and hindbasitarsal combs present, conspicuous. Pulvillus with two lobes. Arolium present. Tergite A8 with an apical row of elongate, tawny stridulatory scales, these angled inside but not forming a ribbon (as in Ambulycini and some Smerinthini).
Male genitalia: Uncus resembling that of Agrius convolvuli in dorsal view but more slender in lateral view, gradually tapering to a point. Gnathos with a broadly rounded medial lobe, convex below. Harpe with a broad, upwardly recurved dorsal hook; ventro-apical hook of other Acherontiini replaced by a series of multiple hooks along entire distal margin. Valve with large patch of multidentate stridulatory scales. Phallus broad, lacking terminal processes.
Female genitalia: Antevaginal plate membranous and folded proximally. Anterior margin of ostium bursae formed into a truncate, feebly sinuate lip with prominent angles. Postvaginal plate more strongly sclerotized, smooth, short.