Thoas Swallowtail (Papilio thoas Swainson)
Wing span: 4 1/8 - 5 inches (10.5 - 12.8 cm).
Identification: Upperside of forewing has diagonal yellow band of square spots in a neat row.
Life history: Caterpillars resemble bird droppings and rest exposed on leaves.
Flight: Year-round in the tropics, April-July in south Texas.
Caterpillar hosts: Plants in the citrus family (Rutaceae) including Citrus spp., prickly ash (Zanthoxylum americanum), hop tree (Ptelea trifoliata); six species in the Piperaceae family.
Adult food: Flower nectar, including lantana, cesalpina, and bougainvilla.
Habitat: Mid-elevation tropical forests and lowland edges.
Range: South Texas south to Brazil. Very rare stray into Kansas and Oklahoma.
Conservation: Not needed in the United States.
Management needs: None in the United States.
The Nature Conservancy Global Rank: G5 - Demonstrably secure globally, though it may be quite rare in parts of its range, especially at the periphery.
Opler, P. A. and V. Malikul. 1992. A field guide to eastern butterflies. Peterson field guide #4. Houghton-Mifflin Co., Boston. 396 pages, 48 color plates. Scott, J. A. 1986. The butterflies of North America. Stanford University Press, Stanford, Calif. 583 pages, 64 color plates.
Author: Jane M. Struttmann
State and Regional References:
Opler, Paul A. 1999. Peterson Field Guide to Western Butterflies, revised edition. Houghton Mifflin Co., Boston, Mass. Stanford, R.E. and P.A. Opler. 1993. Atlas of Western USA Butterflies. Privately published, Denver, Colo.