The mesonotum is the dorsum of the mesothorax, which in flies is well developed and forms most of thorax. The mesonotum includes the scutum, notopleura, scutellum and postnotum. In Tephritidae, the postpronotal lobes are the only dorsally visible parts of the thorax that are not part of the mesonotum. Measure the mesonotum in dorsal view along its midline, from the anterior margin of the scutum to the apex of the scutellum.