- Any of various mosquitoes of the genus <em>Culex,</em> which includes the common house mosquito <em>(C. pipiens)</em> and species that spread diseases such as West Nile virus.
- The typical genus of the family <em>Culicidœ</em>, or gnats. A common species is <em>C. pipiens.</em> See <em>gnat, mosquito.</em>
- A genus of mosquitoes of the family <ex>Culicidae</ex>, to which most of the North American species belong. Some members of this genus are exceedingly annoying, as <spn>Culex sollicitans</spn>, which breeds in enormous numbers in the salt marshes of the Atlantic coast, and <spn>Culex pipiens</spn>, the common house mosquito, breeding very widely in the fresh waters of North America. (For characters distinguishing these from the malaria mosquitoes, see <xref urlencoded="anopheles">anopheles</xref>, above). The yellow-fever mosquito is now placed in another genus, Stegomyia.
- Any of various <xref>mosquitoes</xref> of the genus Culex, some of which carry <xref>disease</xref>
- type genus of the Culicidae: widespread genus of mosquitoes distinguished by holding the body parallel to the resting surface