Mosquitoes and Gnats are part of the order Diptera, just two insects in an order that contains 130 families and 122,000 species. These insects have just one pair of wings; the hindwings are reduced to small, club-shaped balancing organs called halteres. Some are wingless. Two-winged flies are vital pollinators, parasites, predators, and decomposers in all kinds of habitats. Many, however, damage crops or carry diseases that have a huge impact on animals and humans.
 

The body of these delicate, slender flies is covered with patterns of white, gray, brown, and black scales. Some tropical species are brightly colored. The long, narrow wings have scales along the veins and edges, and the mouthparts are very long, slender, and piercing.
 

Eggs are laid on the surface of water, either singly or in groups of 30 to 300. The larvae are saprophragous or eat other mosquito larvae and obtain air from the water surface through an abdominal siphon. Adult females suck the blood of vertebrates but also take plant fluids and nectar; the males feed on plant fluids, nectar, and honeydew. The life cycle usually lasts fewer than three weeks.
 

Worldwide, especially in warm areas. Adults are common near woodland, and larvae are found in virtually any body of freshwater, from a rain-filled treehole or water-butt to a lake.
 

The females of many species carry organisms that cause serious diseases in animals and humans. These diseases include malaria, yellow fever, dengue fever, filariasis, and encephalitis. Malaria is caused by protazoa that belong to the genus Plasmodium and that are parasites of blood. Worldwide, one person dies of malaria every 12 seconds. Despite massive efforts to control the disease, it continues to be a serious, and growing, problem.