Diptera: Flies, Gnats, Midges, Mosquitoes

(from the Greek: di = two + ptera = wings)

All Diptera have sucking mouthparts, and they are the only group of commonly encountered insects which have only 1 pair of wings (instead of 2 pairs). Where the second pair of wings would be located, there is a small structure called a “haltere” which looks like a tiny golf tee and which helps in balance. A few rarely encountered insects in other orders have only 1 pair of wings, such as the Strepsiptera and a few cricket species, but these insects usually have chewing mouthparts. Some rarely encountered flies, such as the sheep ked, are wingless. Fly antennae may be short or long and of various shapes. The eyes are typically very large. In many species, the mouthparts are adapted for piercing plants or animals and sucking sap or blood. In some cases, as with house flies, the mouthparts may be capable of only “sponging” liquid food. House flies are able to feed on solid food only by first dissolving it with excreted saliva.


Flies have complete metamorphosis, and the larvae are usually called maggots. Mosquito larvae are called “wigglers” and their pupae are called “tumblers.” Mosquito tumblers are one of the few kinds of insect pupae are able to move. Many kinds of flies are serious economic pests of plants and animals. Flies are the most important insects in regards to the health of man and animals because of the diseases they spread. Many kinds of flies are beneficial as parasites and predators of pest insects, or as plant pollinators. When writing the common names of true fly species, "fly" is always written as a separate word, such as “house fly,” “deer fly,” or “stable fly.” When "fly" is part of the name of an insect in another order, it is written as a compound word, such as “dragonfly,” “butterfly,” or “caddisfly.”