The hexapoda have the head, thorax, and abdomen differentiated, and are mostly winged. They have three pairs of mouth organs, viz, mandibles, maxillae, and the second maxillae or labial palpi; three pairs of thoracic legs; and abdominal legs, which are present only in some of the lowest forms, and in the larval state of some of the higher ones. Many (the Metabola) undergo a complete metamorphosis, having larvae (known as maggots, grubs, caterpillars) very unlike the adult, and pass through a quiescent pupa state in which no food is taken; others (the Hemimetabola) have larvae much like the adult, expert in lacking wings, and an active pupa, in which rudimentary wings appear. See insecta. The hexapoda are divided into several orders.