The cylindrical larva, or caterpillar , is soft-bodied. The thorax has one pair of legs on each of its three segments. Prolegs are also present on abdominal segments three through ten. Prolegs often have small hooks, called crochets, which the caterpillar uses to cling to vegetation. Spines, bumps, or hairlike structures may be present on the body.
Coloration ranges from protective camouflage to bright warning.
The larvae of some species, such as swallowtails, can produce a disagreeable odor. Butterflies have threadlike, knob-tipped antennae. Depending on the species, eggs may be laid singly or in clusters on or near the host plant. Eggs hatch into the larval, or caterpillar , stage. The larva may molt several times before it pupates .