Rhagastis castor
Similar to Rhagastis acuta and Rhagastis velata but larger, forewings and hindwings more elongate, and generally distinguishable by the combination of the dark connection between the marginal band and the basal area on the forewing underside and the well developed abdominal golden stripes. Labial palp segment 1 apical cavity distinct; segment 2 broadest at base, longer than broad.Abdomen with a pair of golden lateral stripes running from segment 3 or 4 to 7, occasionally reduced in some specimens. Outer row of forebasitarsal spines double. Forewing underside marginal area joined to the basal area by a streak posterior to M2 (connection missing in a few specimens); third postmedial line marked by a series of large and conspicuous black vein dots; medial area with a conspicuous red or salmon pink flush. Hindwing underside medial area with a conspicuous red or salmon pink flush.
Male genitalia: Valve with a single row of large stridulatory scales. Harpe short, somewhat twisted. Phallus apical process asymmetrical, the left lobe more proximal and short, the right lobe rather long, broad and multidentate apically.