The metathorax is the posterior of the three segments in the thorax of an insect, and bears the third pair of legs. Its principal sclerites (exoskeletal plates) are the metanotum (dorsal), the metasternum (ventral), and the metapleuron (lateral) on each side. The metathorax is the segment that bears the hindwings in most winged insects, though sometimes these may be reduced or modified, as in Diptera, in which they are reduced to form halteres, or flightless beetles (Coleoptera), in which they may be completely absent even though forewings are still present. All adult insects possess legs on the metathorax. In most groups of insects, the metanotum is reduced relative to the mesonotum. In the suborder Apocrita of the Hymenoptera, the first abdominal segment is fused to the metathorax, and is then called the propodeum. Diagram of a tsetse fly, showing the head, thorax and abdomen The thorax is a division of an animals body that lies between the head and the abdomen. ... Classes & Orders See taxonomy Insects are invertebrate animals of the Class Insecta, the largest and (on land) most widely-distributed taxon within the phylum Arthropoda. ... An insect leg The arthropod leg is a form of jointed appendage of arthropods, usually used for walking. ... Sclerites are hardened body parts. ... An exoskeleton, in contrast to an endoskeleton, is an external anatomical feature that supports and protects an animals body. ... The word dorsal can refer to many different things. ... In zootomy, several terms are used to describe the location of organs and other structures in the body of bilateral animals. ... The term lateral can refer to: an anatomical definition of direction. ... Suborders Nematocera(Eudiptera) Brachycera Green Bottle Fly Flesh Fly Fannia a Lesser House Fly (unidentified species) Dolichopodidae (unidentified species) Diptera (di - two, ptera – wings), or true flies, is the order of insects in which the hind wings are reduced to halteres. ... Halteres, (singular halter or haltere) from the Greek word for dumbbells, are small knobbed structures homologous to wings and flapped to maintain stability when flying. ... Suborders Adephaga Archostemata Myxophaga Polyphaga See subgroups of the order Coleoptera Beetles are one of the most diverse groups of insects. ... For other uses, see Beetle (disambiguation). ... The mesothorax is the middle of the three segments in the thorax of an insect, and bears the second pair of legs. ... Superfamilies Apoidea Ceraphronoidea Chalcidoidea Chrysidoidea Cynipoidea Evanioidea Ichneumonoidea Megalyroidea Proctotrupoidea Sphecoidea Stephanoidea Triganalyoidea Vespoidea Many families, see article Apocrita is a suborder of insects in the order Hymenoptera. ... Suborders Apocrita Symphyta Many families, see article Hymenoptera is one of the larger orders of Insects, comprising the sawflies, wasps, bees, and ants. ... The abdomen is a part of the body. ...