This is a variable species with strong sexual dimorphism, always conspicuous in the antennae which are combed in the males and plain in the females.

[7][8] The male has upperwings with broad dark brown borders and spots and a background varying from white in the north to deep yellow in southern populations.

The underwings are less dimorphic, orange-brown with darker tips on the forewings and marbled light brown with a whitish lengthwise stripe on the hindwings in both sexes.

[12] It is (under its original scientific name Phalaena piniaria) the type species of its genus Bupalus, as well as the junior objective synonyms Catograpta, Chleuastes and Phaophyga, and the preoccupied Bupala.

[13] Bupalus was raised by the English zoologist William Elford Leach, in 1815 and is the name of a 6th-century BC Greek sculptor.