Diptera is a large order of insects, which includes the true flies; for example: mosquitoes, gnats, midges, house flies, and tsetse flies. Adult flies have soft bodies and one pair of wings, the other being reduced to knob-like halteres. They have compound eyes and sucking mouthparts; some species, e.g., mosquitoes and tsetse flies, have mouthparts specialized for sucking blood and are important transmitters of disease. Dipterans have a complete life cycle: the adult lays eggs that hatch into larvae (maggots), which subsequently these pupate and become adults.