Zerynthia cassandra, commonly known as the Southern Festoon, is a species of butterfly found in southern Europe. It has a wingspan of about 5-6 centimeters and displays a striking pattern of black and yellow markings. The larvae of Zerynthia cassandra feed on Aristolochia plants, which contain toxic compounds that make the caterpillars unpalatable to predators. This species is known for its slow and deliberate flight, often seen gliding gracefully through open meadows and woodland edges.