Britannica
Sources used in this answer
How many functional wings do insects in the order Diptera have?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
Diptera
An adult housefly (Musca domestica) on a doughnut
Insects in the order Diptera possess only one pair of functional wings, which are the forewings.12
The second pair of wings is reduced to small, knob-like structures known as halteres. These organs do not function for flight but instead serve as essential balancing mechanisms for the insect. This unique wing structure is a primary characteristic that distinguishes "true" flies from other insects that may also be referred to as flies, such as dragonflies, caddisflies, and mayflies.12