Hemelytrous

Hemelytrous is a term used to describe the forewings of certain insects, specifically those belonging to the order Hemiptera, which includes true bugs, aphids, cicadas, and leafhoppers. These forewings are distinct from the hindwings and are typically leathery or parchment-like in texture, at least at the base. The apical or outer portion of the hemelytron is often membranous and may be transparent or patterned. This characteristic wing structure is a defining feature of the order Hemiptera.

The hemelytra are not used for fully powered flight in all hemipterans. Instead, they often serve a protective function, shielding the membranous hindwings when the insect is at rest. During flight, both pairs of wings work together, though the hemelytra may contribute less to the propulsive force compared to the hindwings. The structure and venation of hemelytra can vary significantly between different families and even species within the Hemiptera, and these variations are often used by entomologists for classification and identification. The term itself is derived from Greek words, meaning "half" and "wing," referring to the combination of leathery and membranous parts.