Black Swallowtail (Papilio polyxenes)
The Black swallowtail belonging to the swallowtail family is indigenous to a major part of North America, popular for their magnificent and graceful appearance.
Scientific Classification
- Family: Papilionidae
- Genus: Papilio
- Common names: Eastern Black Swallowtail, Parsnip Swallowtail, American Swallowtail
- Scientific Name: Papilio polyxenes
Description and Identification
Caterpillar

Eastern Black Swallowtail Caterpillar
They are black in color with an orange osmeterium (forked gland), resembling the tongue of a snake helping them to fight against their predator. Since they take in poison from the plants they feed on, the caterpillar of these species may not taste good to the birds they prey upon.
Pupa
The chrysalis or pupa has a green or brown body, while a part of it may transform into a dark green hue as the pupa stage comes to an end.
Adult Butterfly
Sexual Dimorphism: Present
Color and Appearance: When the wings are opened, the upper surface has a black coloration with spots of yellow arranged in two rows. The spots appear big and bright in the male species, while in females they look small and light. The space between the rows is blue in color that is more prominent in females and less prominent in males. In the inner part of the hind wing towards the bottom is located a red spot having a black bulls eye, where as a solitary yellow spot is seen on the frontal edge. When the wings are closed the base is black with white blue and orange spots separated by powdery blue regions.
Average Wingspan: 6.9 – 8.4 cm (2.7 – 3.3 inches); females are larger than their male counterparts
Flight Pattern: Fast
Eggs
The female Black swallowtail lays about 200 to 430 eggs at a rate of 30 to 50 on a daily basis. The pale yellow eggs transform into dark gray prior to hatching. The young larva possesses a black and white body, while the older ones are green with yellow spots and a black band.
Quick Facts |
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Distribution | Throughout America including places like Colorado and California, as well as different parts of Canada such as Saskatchewan and Quebec |
Habitat | Open areas such as parks, marshes, deserts and fields |
Lifespan of Adults | Approximately one week |
Host plants | Mock bishopweed ( Ptilimnium capillaceum); Roughfruit scaleseed, (Spermolepis divaricate); Spotted water hemlock (Cicuta maculata); Water cowbane (Oxypolis filiformis); Wedgeleaf eryngo (Eryngium cuneifolium); Canby’s dropwort (Oxypolis canbyi); Queen Anne’s lace (Daucus carota) Dill (Anthem graveolens) |
Adult Diet | Nectar of plants like thistles, clover, phlox, and milkweed |
Did You Know
- They have a close resemblance with the pipevine swallowtail, a poisonous species, hence putting their predators in confusion.
- The black swallowtail caterpillar may not be poisonous but may taste base to its bird predators since they consume toxin from their host plants.
- The caterpillars are known as parsley worm since they feed on parsley.
- The name Polyxenes is derived from Polyxena, a Greek mythological figure who was the Trojan king Priam’s younger daughter.
- The Black swallowtail is New Jersey and Oklahoma’s state butterfly.
Scientific Classification
- Family: Papilionidae
- Genus: Papilio
- Common names: Eastern Black Swallowtail, Parsnip Swallowtail, American Swallowtail
- Scientific Name: Papilio polyxenes