3O4 ENTOMOLOGY 



body forms a curved line, the insect presenting- a hump-backed 

 appearance; in Anopheles the axis forms a straight line. 

 Culex has short maxillary palpi, while in Anopheles they are 

 almost as long as the proboscis. The note of the female 

 Anopheles is several tones lower than that of Culex, and only 

 the female is bloodthirsty, by the way. As regards eggs, 

 larvae and pupge, the two genera differ greatly. The eggs of 

 Culex are laid in a mass and those of Anopheles singly; the 

 larvae of Culex hang from the surface film of a pool at an 

 angle of about forty-five degrees, while those of Anopheles 

 are almost parallel with the surface of the water in which 

 they live. 



The bite of an Anopheles is not necessarily injurious, of 

 course, unless the insect has had recent access to a malarious 

 person. Anopheles may be present where there is no malaria. 

 On the other hand, it has been found impossible to prove that 

 malaria exists where there are no Anopheles mosquitoes. 

 Finally, fevers are sometimes diagnosed as malarial which are 

 not so. 



Possibly the malarial parasite can complete its cycle of 

 development in other animals than man. It is also possible 

 that originally the malarial organism was derived by mos- 

 quitoes from the stems or other parts of aquatic plants, and 

 that its effects on man are incidental phenomena. 



Yellow Fever. It has now been demonstrated that the 

 dreaded disease, yellow fever, is transmitted from one human 

 being to another by the bite of a mosquito (Stegomyia fas- 

 data) and in no other way excepting, of course, by the arti- 

 ficial injection of diseased blood. The discovery of the mode 

 of transmission of the disease was made in Cuba during 1900 

 and 1902 by Dr. Reed and his corps of United States army sur- 

 geons. These investigators succeeded in transmitting the dis- 

 ease to healthy subjects by inoculation from mosquitoes which 

 had previously fed on the blood of yellow fever patients. To 

 convey the disease, however, a period of ten to thirteen 

 days was necessary between the original biting of a patient 



