What are the differences between flies and wasps?

Sometimes it is hard to tell the difference between flies and wasps at first glance. Both flies and wasps are winged, they both tend to 'buzz' around in the garden, and sometimes in the house, and some species can cause irritation by biting or stinging. Some fly species have evolved into mimics of wasps, which can make it even harder to identify them.

However, there are some key features that will help you to work it out.

Head/Eyes

  • Flies: Large, moveable head with large to very large eyes.
  • Wasps: Head not so large in proportion to body and eyes usually large.

Mouthparts

  • Flies: Sucking or piercing and sucking.
  • Wasps: Chewing (sometimes modified).

Antennae

  • Flies: Short to very short antennae (except in some species such as crane flies).
  • Wasps: Variable antennae - can be long and/or curled or relatively short.

Wings

This is the most obvious difference between flies and wasps, but wings can be hard to see when they are moving.

  • Flies: One pair of forewings, which are the only functional wings. The hindwings are reduced to club-like halteres.
  • Wasps: Two pairs of wings, with the hindwings smaller.

Thorax (mid-body section)

  • Flies: Middle segment of thorax (mesothorax) enlarged.
  • Wasps: Thorax not enlarged.

Waist

  • Flies: No distinct waist (except in some wasp/bee mimics).
  • Wasps: Distinct waist (except in sawflies).

Colour/markings

Colour and markings are not always reliable identification tools, but can be used in combination with other features.

  • Flies: Variable, black, brown, metallic blue or green. Wasp mimics can be striped black/yellow.
  • Wasps: Often have warning colours of striped black/yellow or brown/orange, but some species can be metallic blue/green.

Bite or Sting

  • Flies: No sting, but some species can have a painful bite.
  • Wasps: Most species have a sting.

Scientific Classification

  • Flies: Order Diptera, divided into two suborders: Nematocera and Brachycera.
  • Wasps: Order Hymenoptera, Suborder Apocrita.


Dr David Britton , Acting Head, Natural Sciences & Biodiversity Conservation
Last Updated:

Tags diptera, hymenoptera, fly, hornet, arthropods, arthropoda, insects,