Euproserpinus phaeton (Phaeton primrose sphinx moth) is a moth of the family Sphingidae. It is found from California south to Baja California Sur and further into Mexico. It has also been reported in south-western Arizona. The length of the forewings is 32–42 mm. The abdomen upperside has creamy white side-tufts and a discontinuous dorsal white band. The forewing upperside has a median area which is mainly lacking transverse lines. The hindwing upperside has a straight marginal black band with some black scales. The hindwing underside is lacking black basally.