AEDES CALOPUS AND YELLOW FEVER 443 



enough individuals do this to make it necessary to look for 

 breeding places more than three or four hundred yards from the 

 infested locality. The conveyance of mosquitoes in trains, 

 boats, etc., must, however, be taken into account. 



The effect of anti- Anopheles campaigns on the prevalence of 

 malaria is discussed in Chap. IX, pp. 165-167. 



Mosquitoes and Yellow Fever 



Following upon the heels of the discovery of the relation of 

 mosquitoes to malaria, and second only to it in importance, came 

 the discovery of a similar relation to yellow fever, in 1900. As 

 in the case of malaria, some physi- 

 cians suspected the instrumentality 

 of mosquitoes in the dissemination of 

 this disease before there was any 

 proof of it. The proof came as the 

 result of the illustrious work of the 

 American Army Yellow Fever Com- 

 mission, composed of Doctors Reed, 

 Carroll, Lazear, and Agramonte, at 

 the cost, indirectly, of the lives of 

 three of them. What is known of 

 the nature of yellow fever, and of 

 the role of the mosquito in trans- 

 mitting it, is discussed in Chap. X, 

 pp. 182-185. It should be repeated 

 here, however, that the "germ" of the 

 disease is still unknown, though be- 

 lieved to be a protozoan. The blood 

 of a patient can infect a mosquito FlG - 201 - Yellow fever mos- 

 only during the first three days of $D*) mhpu ' ' emale - 

 illness, and the mosquito cannot 



transmit the disease in less than 12 days later. In one case, 

 hereditary transmission of yellow fever from an infected mosquito 

 to its offspring has been shown to occur. 



The Transmitting Species, Aedes calopus. Unlike the condi- 

 tion as regards malaria, yellow fever can be transmitted by only 

 one species of mosquito, Aedes calopus (or Stegomyia fasciatus) 

 (Fig. 201). This is a small black mosquito, conspicuously 

 marked by white bands on the legs and abdomen, and a white 



