Giant Swallowtail (Papilio cresphontes) (Cramer 1777)

Diagnosis: The largest butterfly found in Canada (wingspan: 83 to 113 mm), the Giant Swallowtail has broad dark brown wings crossed on the upperside by a diagonal band of bright yellow spots. The underside is yellowish and the tail is broad with a yellow spot in the centre.

Subspecies: The race of the butterfly reaching southern Canada has been referred to as subspecies pennsylvanicus, but it is only weakly differentiated from the nominate subspecies and is not currently recognized.

Range: A common and widespread tropical species, it ranges from Central America northward through the eastern U.S. to the Canadian border. In Canada, it is a resident species in southwestern Ontario, but strays have been taken in Winnipeg, Montreal, and one specimen near Windsor Junction in southern Nova Scotia. In 1992, a stray was recorded in the Ottawa area for the first time following high winds resulting from a hurricane in the southern U.S.

Specimen collection data

Similar Species: None in Canada.

Early Stages: The larva is called the "Orange Dog" in the U.S., where it can be a pest in citrus orchards. It is brown with a light cream saddle in the middle and a large cream patch on the tail, resembling a large bird dropping. It has been recorded on Hop Tree (Ptelea trifoliata) and Northern Prickly-ash (Zanthoxylum americanum) in Ontario. Both plants are common at Point Pelee, where the larvae can be found.

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Abundance: It is considered sporadic and rare in Canada, except in southwestern Ontario, where it can be commonly encountered at Point Pelee, Pelee Island, and a few other locations where the foodplants grow.

Flight Season: Two generations have been recorded at its northern limit, the second being the more common. It flies from late May into July and again from late July into early September. At Point Pelee there is a partial third brood later in September, but cresphontes is most commonly seen in August (Wormington, 1983).

Habits: The Giant Swallowtail flies in open woodlands and nearby fields. It is such a large butterfly that it continually vibrates its wings while feeding at flowers so that it does not tilt the blossom.

© 2002. This material is reproduced with permission from The Butterflies of Canada by Ross A. Layberry, Peter W. Hall, and J. Donald Lafontaine. University of Toronto Press; 1998. Specimen photos courtesy of John T. Fowler.