The Collaborative International Dictionary of English v.0.48:

Anopheles \A*noph"e*les\ ([.a]*n[o^]f"[-e]*l[=e]z), n. [NL., fr.
   Gr. 'anwfelh`s useless, hurtful.] (Zool.)
   A genus of mosquitoes which are secondary hosts of the
   malaria parasites, and whose bite is the usual, if not the
   only, means of infecting human beings with malaria. Several
   species are found in the United States. They may be
   distinguished from the ordinary mosquitoes of the genus
   Culex by the long slender palpi, nearly equaling the beak
   in length, while those of the female Culex are very short.
   They also assume different positions when resting, Culex
   usually holding the body parallel to the surface on which it
   rests and keeping the head and beak bent at an angle, while
   Anopheles holds the body at an angle with the surface and
   the head and beak in line with it. Unless they become
   themselves infected by previously biting a subject affected
   with malaria, the insects cannot transmit the disease.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

Anopheles
    n 1: malaria mosquitoes; distinguished by the adult's head-
         downward stance and absence of breathing tubes in the
         larvae [syn: Anopheles, genus Anopheles]