The wings of these butterflies are white on top and greenish-yellow beneath, and their bodies are black. The forewings have black tips and round black spots. The males and females can be distinguished by the number of spots on their forewings: the males have one per wing, and the females, two. Both sexes have a single black spot on their hindwings. Their wingspan varies from 3 to 5.8 cm.
The caterpillars are green or blue-green and covered with short, fine hairs. They are up to 3.5 cm long.