The Whole Equals the Sum of Its Parts
Butterflies and their close relatives, the moths, make up the insect order Lepidoptera. Like all insects, butterflies have six jointed legs, three body segments (head, thorax, abdomen), and a pair of antennae. Lepidopterans have specialized wings covered with scales. The scales are what give the butterfly's wings such brilliant colors.
The head of a butterfly bears two antennae, two compound eyes, two palpi, and a coiled proboscis. (See diagram below.) The antennae provide sensory information to the butterfly, primarily in the form of scent. The compound eyes provide a complex form of sight. The palpi (sing. palpus) provide sensory information and serve to protect the proboscis. The proboscis is the sucking mouthpart through which the butterfly takes up nectar and other sources of nutrients.
The thorax is the body segment behind the butterfly's head. It houses the important wing muscles, and is where the wings and the three pairs of legs are attached. The wings come in two pairs, a pair of forewings and a pair of hindwings. The wings are divided into small sections by veins, which provide the structural scaffolding of the wing. Each wing is covered with overlapping scales of several sorts - pigment, refractive, and sex scales.
The abdomen is very much the working end of the butterfly in that it houses the organs necessary for digestion and reproduction. These organs include those necessary for mating and, in females, for laying eggs.