tegumen

The tegumen is a term used in biology, particularly in entomology, to refer to the dorsal or upper part of the abdomen in insects. It is essentially the hardened upper shell of the abdominal segments. The tegumen is derived from the tergites, which are the dorsal plates of the exoskeleton. In many insect species, the tegumen is a prominent feature and plays a role in protecting the internal organs of the abdomen. Its appearance and structure can vary significantly between different insect groups, often providing important diagnostic characteristics for identification. For example, the shape, texture, and ornamentation of the tegumen can be unique to a particular genus or species. In some insects, the tegumen may be fused or modified to form specialized structures. The term is also sometimes used in a broader sense to refer to any dorsal covering or shell.