Adult mosquitoes have only one pair of wings. A single pair of wings is a constant trait for all mosquitoes and other members of the Diptera order, commonly referred to as true flies.
There are over 3,000 documented species of mosquitoes worldwide, which all have single pairs of wings. During the mosquito life cycle, eggs transition to larvae and then to pupae before hatching into adults. Wings are only visible on mosquitoes in the adult stage of their life cycle. Other common true flies that have only one set of wings include gnats, house flies, horse flies, midges, fruit flies and crane flies.