Rhagastis castor

Rhagastis castor is a moth of the family Sphingidae first described by Francis Walker in 1856.

Distribution
It is known from Nepal, north-eastern India, Thailand, southern China and Vietnam, Sumatra, Java and Taiwan.

Description
The wingspan is 53–84 mm. It is similar to Rhagastis acuta and Rhagastis velata but larger, the forewings and hindwings are more elongate. It is 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. The forewing underside marginal area is joined to the basal area by a streak. The third postmedian line is marked by a series of large and conspicuous black vein dots. The forewing and hindwing median area has a conspicuous red or salmon pink flush.

Biology
Larvae of subspecies R. c. aurifera have been recorded feeding on Amorphophallus and Vitis species in India. The larvae of subspecies R. c. formosana feed on Saurauia species.

Subspecies

 * Rhagastis castor castor (Sumatra and Java)
 * Rhagastis castor aurifera (Butler, 1875) (Nepal, north-eastern India, Thailand, southern China and Vietnam)
 * Rhagastis castor formosana Clark, 1925 (Taiwan)
 * Rhagastis castor jordani Oberthür, 1904 (southern China)