from
The Collaborative International Dictionary of English v.0.48
Culex \Cu"lex\, n. [L., a gnat.] (Zool.)
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}.
Note: This genus formerly (ca. 1900) included the gnat as
well as the mosquito.
[Webster 1913 Suppl. +PJC]