List of butterflies of North America (Papilionidae)

Swallowtails are the largest butterflies. They range in size from 2.5–6.4 inches (6.5–16.5 cm). There are about 600 species worldwide with about 31 species in North America. All swallowtails have tails on their hindwings (except the parnassians). Their flight is slow and gliding but, when disturbed, their flight can be quite strong and rapid. They like to feed on various flowers, dung, and urine, and males like to puddle on damp ground. Most male swallowtails locate females by patrolling, and some males perch. The eggs are round and usually laid singly on different kinds of host plants. The larvae have a reddish-orange forked gland, called an osmeterium just behind the head. When frightened, the larva thrusts the gland out releasing a foul odor that will sometimes deter a predator. Many young swallowtail larvae resemble bird droppings. The chrysalis of most species is brown or green and looks like a leaf or branch. It is held upright by a silken loop around the middle called a girdle. The swallowtails overwinter as a chrysalis.

Black swallowtail, Papilio polyxenes, chrysalis