A genus of mosquitoes of the family Culicidae, to which most of the North American species belong. Some members of this genus are exceedingly annoying, as Culex sollicitans, which breeds in enormous numbers in the salt marshes of the Atlantic coast, and Culex pipiens, the common house mosquito, breeding very widely in the fresh waters of North America. (For characters distinguishing these from the malaria mosquitoes, see Anopheles, above). The yellow-fever mosquito is now placed in another genus, Stegomyia.

type genus of the Culicidae: widespread genus of mosquitoes distinguished by holding the body parallel to the resting surface

Culex is a genus of mosquito, and several species act as vectors of important diseases, such as West Nile virus, filariasis, Japanese encephalitis, St. Louis encephalitis and avian malaria.