Fruit flies are among the smallest members of the Order Diptera and have large, pronounced compound eyes, oval-shaped bodies and a set of four wings, much like larger flies. Fruit flies average approximately 1 millimeter in length, and females are slightly larger than males. They closely resemble many fly species in appearance, sharing the same unique body shape, large wings and bulging eyes, but have several key biological differences.
Fruit flies are separated biologically from their closest relatives by their pectinate aristae, which are tiny hair-like structures that cover their antennae. Fruit flies beat their wings more rapidly and aggressively in flight than their larger cousins, which gives them a distinctive, higher-pitched buzzing sound while flying through the air than most other flies. As with others in the Order Diptera, fruit flies vary in color depending on the species. Some are vibrant and vivid and have bodies and wings colored in bright orange, crimson and gold, while others are dark blue, gray and black. Fruit flies have long antennae, which may be twice the size of their body length. These antennae are equipped with tiny feelers at the end that guide the flies to their food supplies. Fruit flies have oversized compound eyes, like most insects, which essentially give them 3-D vision.