The common name 'Argent and Sable' which was given to this species in 1778 refers to the colour of the moth. Argent is a silvery-white colour and sable is black, both terms especially used in heraldry (4). Both the fore- and hindwings are white in colour with variable black markings (3). The caterpillar has a stumpy appearance, and is dark green in colour with a black head and a black line passing along the length of the back (3).