Pterygota

The Pterygota are a subclass of insects that includes all winged insects, as well as those that have become secondarily wingless. This group is distinguished by the presence of wings, which develop as outgrowths of the thorax and are supported by veins. The consistent pattern of these veins, known as venation, is crucial for classifying different insect groups and suggests that wings evolved only once in insects, with all Pterygota descending from a single ancestral lineage.12

While the exact evolutionary path of wings is debated, one hypothesis suggests they began as gliding planes that later developed musculature for flapping flight. Another theory proposes wings may have originated from thoracic tracheal gills. The Pterygota are further divided into Paleoptera, whose wings remain extended or held aloft, and Neoptera, which possess a mechanism to fold their wings back over their abdomen. Many Pterygota species have evolved to be secondarily wingless.2