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Pale Swallowtail (Papilio eurymedon)

The Pale Swallowtail is a species under the ‘swallowtail’ group of butterflies native to the western regions of North America. They are known for their elegant black-and-white appearance and pointed wings and are often seen puddling in the mud.

Scientific Classification

Family: Papilionidae
Genus: Papilio
Common names: Pallid Swallowtail
Scientific Name: Papilio eurymedon

Description and Identification

Caterpillar

The caterpillars are up to 5 cm in length and are born green, with distinct and weird eye marks to scare of predators. There is also a long mark behind the eye marks to render the appearance of a head. Mature larvae gradually turn tan to reddish before they metamorphose into a pupa.

Pupa

The chrysalis is either pale olive green, or light brown, and hangs from the firm branches of its host plant using its silk threads. They hibernate during winter if the season coincides with this stage.

Adult Butterfly

Sexual Dimorphism: Not present

Color and Appearance: When the wings are open, the dorsal side of the wings displays a creamy or off-white coloration with about four black stripes that run parallel to its body and gradually decreasing by size, ending near the wingtip. While the primary wings are narrow and pointed towards the end, the dorsal wing is much shorter, giving the creature a roughly triangular look. There is a long and twisted tail-like structure at the end of each of the hind wings. Both the wings have thick black borders with white stitch-like marks. At the end of the rear wings, there are a few small orange and cyan markings. When the wings are closed, they show an exact mirror image of the dorsal side, except that, the patterns are somewhat smudged and faded.

Average wingspan: Typically 3.5 to 4.5 inches (8.9 to 11.4 cm)

Flight pattern: Moderate

Eggs

Green, or green with slightly reddish hues, and are laid singly on host plant leaves

Quick Facts
Distribution	In a vast region in the western part of North America, including British Columbia east to Montana, southern parts of New Mexico, California, and Baja California
Habitat	Sunny foothills, shrubby forest areas, open woodlands and streamsides
Host plants	Trees and shrubs in the Betulaceae, Rhamnaceae, and Rosaceae families that includes cherry (Prunus emarginata), coffee-berry (Rhamnus californica), and ash (Fraxinus spp.)
Adult diet	Nectar from flowers including wallflower, California buckeye, and yerba santa

Did You Know?

Scores and dozens of males of the species can be seen flocking in large numbers at puddling parties (where they might also join other species) to suck water from moist soil for obtaining nutrients to help them in mating.