Nobody knows exactly how insect wings evolved, but winged insects have been flying about for at least 300 million years. Fossil evidence suggests that wings only evolved once in the insect lineage, and develop as paired outgrowths from the thorax, stiffened by ribs, or veins, which are innervated by tracheae.

Insect wings are thought to have evolved from a gill-like thoracic segment present in early insects, which enabled insects to increase the area available for finding food, shelter, and for breeding. While at rest, many insects fold their wings, spread the appendages horizontally, or position them sloped over their backs. A few insects wrap the outstretched wings around their bodies. Insects have either two or four wings, which are used in various ways to coordinate flight, protect the insect, or to attract a mate.

During flight, insects beat their wings rapidly, with houseflies having an average repetition of about 200 beats per second. Flies travel at a top speed of four and a half miles per hour, far slower than the dragonfly, which can speed up to 15 miles per hour. Many insects are easily identified by their distinctive wing shapes, colors, and patterns.