Damselflies are flying insects of the suborder Zygoptera in the order Odonata. They are similar to dragonflies but are usually smaller and have slimmer bodies. Most species fold the wings along the body when at rest, unlike dragonflies which hold the wings flat and away from the body. Damselflies have existed since the Jurassic, and are found on every continent except Antarctica.

The Pterygota are a subclass of insects that includes all winged insects and the orders that are secondarily wingless.