Being true flies, midges (in the family Chironomidae) have only one pair of wings. They look a lot like mosquitoes: small and dainty, rather soft-bodied, with long, narrow wings and long, skinny legs; males often have feathery antennae, used for sensing the high-pitched sounds of female wings. Unlike mosquitoes, midges, at rest, tend to hold their first pair of legs forward and upward (while many mosquitoes, at rest, hold their hind legs outward and upward). A midge's up- and outstretched forelegs can resemble antennae, at a glance. The tarsi ("foot" portion) of the forelegs, in many midges, is very long. Midges lack scales on their wings (while mosquitoes' wings do have scales). Fine details of anatomy, including wing venation, are important for identifying midges beyond the most basic groups (tribe, subfamily, or genus).
The larvae of many midges are called bloodworms, for they are red from the hemoglobin molecules within their narrow bodies. They live at the bottom of lakes, ponds, and other aquatic habitats and often construct tubes from fine sediment and mucus.
Similar species: In addition to mosquitoes, there are other entire families of flies that look similar: the biting midges or "no-see-ums" (Ceratopogonidae), the black flies (Simuliidae), the phantom midges (Chaoboridae) (named for their see-through, swimming wormlike larvae), the meniscus or dixid midges (Dixidae) (named for the U-shaped position their larvae assume while resting at the water's meniscus, the "bend" that water makes at its edges), and more. Some people confuse crane flies with mosquitoes and midges, plus there are less closely related flies that have long legs and long, narrow wings, too.