·add. ·noun 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.