A fly that is designed to stay above the surface of the water.

An insect imitation representing the fully emerged winged insect sitting on the waters surface as it dries its wings.

any fly fished upon the surface of the water; usually constructed of non-water-absorbent materials; most commonly used to imitate the adult stage of aquatic insects.

Floating insect imitation, often of the adult (image) form; in mayfly imitations, may be tied as a dun or spinner.