Culex

1. 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.
   

This genus formerly (ca. 1900) included the gnat as well as the mosquito.