National Museum of Natural Science

The Western tiger swallowtail is a member of the subgenus Pterourus that began to diverge during the Pliocene. Wingspan is 7-10 cm. The base color of the wings is yellow. There are black bands along the outer margins of the forewings and some short black stripes along the anterior margins, resembling tiger stripes. The outer margins of the hindwings are wavy. The tail extension is short and there are meniscus-shaped yellow markings on the outer margin black bands, with blue markings embedded in the black bands. The larvae feed on birch, poplar, and willow trees. Distribution is in western North America.

Papilio rutulus