In some groups of insects, the mesonotum is hypertrophied, such as in Diptera, Hymenoptera, and Lepidoptera), in which the anterior portion of the mesonotum (called the mesoscutum, or simply "scutum") forms most of the dorsal surface of the thorax.
For example, in Diptera, Hymenoptera, and Lepidoptera, the mesonotum is the most hypertrophied sclerite, and is commonly called the scutum.