The scutellum is the posterior portion of either the mesonotum or the metanotum of an insect thorax; however, it is used almost exclusively in the former context, as the metanotum is rather reduced in most insect groups. In the Hemiptera, and some Coleoptera, the scutellum is a small triangular plate behind the pronotum and between the forewing bases.[1] In Diptera and Hymenoptera the scutellum is nearly always distinct, but much smaller than (and immediately posterior to) the mesoscutum.