The thorax is the segments of an insect that comes after the head and before the abdomen. It consists of a series of  upper and  lower  plates known as the notum and  pleuron. The thorax is divided into three segments called  the prothorax  the mesothorax and the metathorax.  Conected to each segment of the thorax is a pair of segmented legs. In pterygotes or winged insects, the fist two thoractic segments ontain wings. Members of the insect order Diptera have only one pair of wings  on the protharax, while the mesothorax contains nub-like balances called halteres.