Caterpillars are Lepidoptera (butterfly) larvae which, from hatching to pupation, go through several stages characterized by successive molts. Like all insects, they consist of three parts (head, thorax and abdomen). The head or cephalic capsule has in particular mouthparts comprising mandibles intended to grind food and palps with a sensory function to which are added a pair of antennae. Each of the three segments of the thorax bears a pair of true legs. Articulated and equipped with a claw, they have a prehensile function when feeding. Some of the ten caterpillar abdomen segments bear prolegs which are not jointed but equipped with hooks. They are used for locomotion and support on branches or leaves.