Papilio multicaudata
Two-Tailed Swallowtail

Family: Papilionidae
Family Description:
Alternate Common Name: Two-Tailed Tiger Swallowtail.
Note: Some sources refer to this species with an alternate genus name, Pterourus. Occasionally, the older genus name, Euphoeades, may be used.
Caterpillar: The caterpillar is light green and marked near the head with four yellow dots and two yellowish eyespots with blue centers. The "neck" is banded with black and yellow, and the body has several rows of tiny blue dots. The caterpillar turns brownish or reddish in the last stage prior to pupation.
Adult: The butterfly is large, with a wingspan of 3 to 5 inches. The upperside is yellow to orangish yellow and edged thickly with black. Each side of the butterfly has four narrow, diagonal, nearly parallel stripes; the innermost stripe is the longest, while the outermost two may simply be bars. The hindwing has a curved row of blue patches; below the blue are several bars or spots of orange. There are two tails extending from the rear of the hindwing, with the innermost tail considerably shorter. The underside is marked similarly. The underside of the hindwing is edged with black, then blue, then yellow bars.

This species ranges from southern British Columbia and Alberta south through the western half of the U.S. to western Texas and into Mexico. The range extends east as far as the western edge of the Dakotas, central Nebraska, and Oklahoma’s panhandle. In Idaho, it occurs throughout much of the state.

It uses a variety of habitats, including canyonlands, foothills, valleys, woodlands, and gardens.

Caterpillars feed on the leaves of a variety of trees and shrubs, including ash (Fraxinus spp.) and cherry (Prunus spp.).

Adult: Butterflies drink flower nectar.

Caterpillars construct small feeding structures from folded leaves tied and lined with silk. The number of generations of caterpillars produced each year varies with location, with only one in the north, several in the south, and many in Texas. Pupae present at the end of the growing season overwinter in a physiological state called diapause, although occasionally some finish pupating and emerge as adults that same autumn. Adults generally fly from April to October in the northern part of its range, and fly most of the year in the southern part of its range.

Males actively patrol in search of receptive females. Females lay eggs singly on host plant leaves.

Idaho Status: Unprotected nongame species.
Global Rank:

G5; populations are widespread, abundant, and secure.

Ferris, C. D. and F. M. Brown. (eds.) 1981. Butterflies of the Rocky Mountain States. Univ. of Oklahoma Press, Norman, Oklahoma, USA, 442 pp.

Opler, P. A., H. Pavulaan, and R. E. Stanford. 1995. Butterflies of North America. Jamestown, North Dakota, USA: Northern Prairie Wildlife Research Center Home Page. (Version 05Nov98).

Opler, P. A. and A. B.Wright. 1999. A Field Guide to the Western Butterflies.   Second Edition.  Peterson Field Guide Series. Houghton Mifflin Company, New York, New York, USA, 540 pp.

Pyle, R. M. 1981. National Audubon Society Field Guide to North American Butterflies. Alfred A. Knopf, Inc., New York, New York, USA, 924 pp.

Scott, J. A. 1986. The Butterflies of North America. Stanford University Press, Stanford, California, USA, 583 pp.

Stanford, R. E. and P. A. Opler. 1993. Atlas of Western U.S.A. Butterflies (Including Adjacent Parts of Canada and Mexico). Published by authors, Denver, Colorado, USA, 275 pp.