Zebra Swallowtail

The zebra swallowtail has a wingspan of 6.4 to 10.4 cm (2.5 to 4.1 in). The triangular wings are white to greenish white with black longitudinal stripes. A pair of swordlike tails extend from the hindwings. The inner margin of the hindwing has two blue spots on the corner and a red spot near the body. A red stripe runs along the middle of the ventral hindwing. P. marcellus has two seasonal forms, one occurring in the spring and the other in the summer. Spring forms are smaller, more white, and have short, black tails with white tips. Summer forms are larger, have broader black stripes, and longer, black tails with white edges.

Males will patrol near host plants in search of females, flying swiftly and directly. They usually fly 0.5 to 1.8 meters (1.6 to 5.9 ft) above the ground. Females will fly slowly when searching for suitable host plants. Both males and females avidly visit flowers, including species from the families Apocynaceae, Brassicaceae, Fabaceae, Lythraceae, Polemoniaceae, and Rosaceae. Males participate in a behavior known as puddling, in which individuals congregate on sand, gravel, or moist soil to obtain salts and amino acids. These nutrients aid the male in reproduction. Other food sources include rotting fruit and urine.