mesophragma
/ˌmɛsə(ʊ)ˈfraɡmə/Entomology
noun
In certain insects: an inward extension of the exoskeleton which forms a transverse partition separating the mesothorax from the metathorax.
Origin
Early 19th century; earliest use found in William Kirby (1759–1850), entomologist and naturalist. From meso- + phragma. Compare mesophragm.