True Flies, Order Diptera

Habits and Traits of True Flies

Close-up of a fly.

Martin Deja/Getty Images

Insects of the order Diptera, the true flies, are a large and diverse group that includes midges, no-see-ums, gnats, mosquitoes, and all manner of flies. Diptera literally means "two wings," the unifying characteristic of this group.


As the name, Diptera indicates, most true flies have just one pair of functional wings. A pair of modified wings called halteres replace the hindwings. The halteres connect to a nerve-filled socket and work much like a gyroscope to keep the fly on the course and stabilize its flight.

Most Dipterans use sponging mouthparts to lap juices from fruits, nectar, or fluids exuded from animals. If you've ever encountered a horse or deer fly, you probably know that other flies have piercing, biting mouthparts to feed on the blood of vertebrate hosts. Flies have large compound eyes.

Flies undergo complete metamorphosis. The larvae lack legs and look like small grubs. Fly larvae are called maggots.

Most insect taxonomists divide the order Diptera into two suborders: Nematocera, flies with long antennae like mosquitoes, and Brachycera, flies with short antennae like house flies.

Habitat and Distribution

True flies live in abundance worldwide, though their larvae generally require a moist environment of some kind. Scientists describe over 120,000 species in this order.

Major Families in the Order

  • Culicidae - mosquitoes
  • Tipulidae – crane flies
  • Simuliidae – black flies
  • Muscidae – house flies
  • Cecidomyiidae – gall midges
  • Calliphoridae – blowflies
  • Drosophilidae – pomace flies

Dipterans of Interest

  • Mormotomyia hirsute is only known to live in a large crack at the top of Kenya's Ukazzi Hill. Its larvae feed on bat dung.
  • Humans share over 20 percent of our DNA with Drosophila melanogaster, the fruit fly commonly used to teach genetics in high school science labs.
  • Flower flies in the family Syrphidae mimic ants, bees, and wasps; despite their convincing costumes, flies cannot sting.
  • Blowfly larvae feeding on dead bodies can help forensic scientists determine the time of the death of the victim.


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Your Citation
Hadley, Debbie. "True Flies, Order Diptera." ThoughtCo, Aug. 26, 2020, Hadley, Debbie. (2020, August 26). True Flies, Order Diptera. Retrieved from Hadley, Debbie. "True Flies, Order Diptera." ThoughtCo. (accessed May 28, 2023).