Tegmen

The tegmen (plural: tegmina) refers to a modified, hardened forewing found in certain insect orders, most notably Orthoptera (grasshoppers, crickets, and katydids) and Blattodea (cockroaches). Unlike the membranous hindwings used for flight, the tegmen is typically more leathery or parchment-like in texture.

The primary function of the tegmen is to protect the delicate hindwings when the insect is not flying. It serves as a protective covering over the folded hindwings, shielding them from damage from the environment, predators, and physical abrasion. While the tegmen can contribute to flight, its aerodynamic capabilities are generally less significant compared to the hindwings. In some species, the tegmen also contributes to camouflage by blending with the surrounding environment.

In Orthoptera, the tegmen can also be involved in sound production (stridulation). Some species possess specialized structures on the tegmen (often ridges or pegs) that, when rubbed against another body part (like the legs or another part of the tegmen), create the characteristic chirping or buzzing sounds used for mating calls and territorial displays.