<Table> <Tr> <Td> </Td> </Tr> <Tr> <Td> </Td> </Tr> </Table> <Table> <Tr> <Td> </Td> </Tr> <Tr> <Td> </Td> </Tr> </Table> <P> The insect thorax has three segments: the prothorax, mesothorax, and metathorax . The anterior segment, closest to the head, is the prothorax; its major features are the first pair of legs and the pronotum . The middle segment is the mesothorax; its major features are the second pair of legs and the anterior wings, if any . The third, the posterior, thoracic segment, abutting the abdomen, is the metathorax, which bears the third pair of legs and the posterior wings . Each segment is dilineated by an intersegmental suture . Each segment has four basic regions . The dorsal surface is called the tergum (or notum) to distinguish it from the abdominal terga . The two lateral regions are called the pleura (singular: pleuron), and the ventral aspect is called the sternum . In turn, the notum of the prothorax is called the pronotum, the notum for the mesothorax is called the mesonotum and the notum for the metathorax is called the metanotum . Continuing with this logic, there is also the mesopleura and metapleura, as well as the mesosternum and metasternum . </P> <P> The tergal plates of the thorax are simple structures in apterygotes and in many immature insects, but are variously modified in winged adults . The pterothoracic nota each have two main divisions: the anterior, wing - bearing alinotum and the posterior, phragma - bearing postnotum . Phragmata (singular: phragma) are plate - like apodemes that extend inwards below the antecostal sutures, marking the primary intersegmental folds between segments; phragmata provide attachment for the longitudinal flight muscles . Each alinotum (sometimes confusingly referred to as a "notum") may be traversed by sutures that mark the position of internal strengthening ridges, and commonly divides the plate into three areas: the anterior prescutum, the scutum, and the smaller posterior scutellum . The lateral pleural sclerites are believed to be derived from the subcoxal segment of the ancestral insect leg . These sclerites may be separate, as in silverfish, or fused into an almost continuous sclerotic area, as in most winged insects . </P>

Where is the notum found on the insect