Culex \Cu"lex\, n. [L., a gnat.]

(Zo["o]l.) A genus of mosquitoes to which most of the North American species belong. Some members of this genus are exceedingly annoying, as C. sollicitans, which breeds in enormous numbers in the salt marshes of the Atlantic coast, and C. pipiens, 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.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Culex \Cu"lex\ (k?"l?ks), n. [L., a gnat.]

(Zo["o]l.) A genus of dipterous insects, including the gnat and mosquito.

Source: Webster's Revised Unabridged Dictionary (1913)