Introduction  Mouthparts  Development

Insect Orders

Other Arthropods
 Spiders, etc.

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Order Diptera: Flies, mosquitoes, gnats, and midges.

The this group is the true flies. Diptera means 'two winged', and flies have only two wings. The other groups we have discussed have either four wings or no wings at all. Flies have complete metamorphosis. Flies have several types of mouthparts. For example, mosquito adults have piercing-sucking mouthparts, deer flies have biting, and others sponging. Most of the larvae are legless.

Pictured above is a flower fly adult and a larva. Note that this larva is an aphid predator.

Kentucky Examples of the Order Diptera:

This is another example of complete metamorphosis with flies. This is a crane fly larva, referred to as a leatherjacket. Adult crane flies like the one in the corner are sometimes referred to as mosquito hawks. However, they are not pests like mosquitoes, in fact they do not feed in the adult stage.

This is a species of soldier fly. In this photo the two wings can be seen clearly as well as a short knoblike process behind one of the lower wings. This knoblike process is called a haltere and replaces a hind wing for flies. The one on the other side is not clearly visible.

Some flies are beneficial, as is this one. This is a tachinid parasitoid that attacks squash bugs. The female deposits her egg directly on the squash bug, the egg hatches and the fly larva enters and feeds on the squash bug. Parasitoids are parasites that kill their prey.

The black horse fly is the largest of the horse fly species in Kentucky. This horse fly is a blood feeder, slashing the hide of the animal and sponging blood from the wound.

One of the more unpleasant encounters in the landscape is the mosquito. Some of the mosquito females are blood feeders, others feed on pollen and nectar. Larvae are aquatic and filter feeders. Male mosquitoes are not blood feeders. Several species of mosquitoes are of importance as vectors of human diseases.

Flies play important roles in the environment, while some are serious pests, others are predators, parasitoids, scavengers, or pollinators.

Updated November 2005

Photo credits:  R. Bessin, Department of Entomology, University of Kentucky; montage created by P. Dillon, Department of Entomology, University of Kentucky

The teaching modules on this site were created by Ric Bessin;
web functionality was created and is maintained by Pat Dillon
Department of Entomology, University of Kentucky, S-225 Agricultural Science Ctr North, Lexington, KY USA  40546-0091.
Please send questions or suggestions to: rbessin@uky.edu OR pdillon@uky.edu