Pterygota plural proper noun - winged insects, a subclass of
Insecta. The group Pterygota comprises the majority of insects, and the ones most often encountered. A specific member of this group is called a
pterygote. Pterygota have veined wings on the second and third thoracic segments. Some members of the Pterygota have secondarily lost wings. This occurs when a lifestyle, such as parasitism, or subterranean life, makes wings, and flight, disadvantageous. There are examples in many groups. In these cases, wingless forms have close relatives with wings. All winged insects are believed to have evolved from a single ancestor, i.e., this is a
monophyletic group.
According to this
Tree of Life article there are three prominent evolutionary lines of living winged insects:
2-
Odonata--dragonflies and damselflies
3-
Neoptera--all other winged insects. These have a sophisticated mechanism for folding the wings over the back.
Sometimes Ephemeroptera and Odonata are placed in a group, the
Paleoptera (old-winged), though others have placed these, in various combinations, with the Neoptera. An important group under the neoptera is
Endopterygota (Holometabola), insects with complete metamorphosis. This includes the neuroptera and subsequent orders in the traditional classification.
Compare the above to the most commonly encountered non-winged insects (
Apterygota), the orders
Zygentoma (Silverfish) and
Microcoryphia (Bristletails).
