A large (6.5-9.0 cm. wingspan) long-winged and heavy-bodied moth. The forewing is black, with a wide cream-yellow stripe running the length of it and a wide, blue-grey terminal band, all rather sharply separated. The hindwing is black with a wide rose-pink median band and a narrower terminal one, and with a white spot in the anal angle. The similar H. euphorbiae has a mainly light brown forewing freckled with dark spots, and with the black costa replaced by two dark brown spots. H. lineata has the forewing veins outlined in white scales.