MOSQUITOES AND YELLOW FEVER 133 



characteristic. In the case of yellow fever, why should 

 one species of Culex be able to transmit the disease and 

 not another species, assuming, as it will be quite proper 

 to assume, that since this capacity appears to be of generic 

 importance with Anopheles, it would be of generic im- 



FiG. 33. — Body Scales from Stegomyia fasciata ; the broad one from a 

 wliite stripe and the narrow one from a chirk surface ; greatly en- 

 larged. (From Photo-micrograph by Dr. Erwin F. Smith.) 



portance in the case of yellow fever ? It happens that the 

 British Museum is investigating the mosquitoes of the 

 world. Specimens have been sent to the expert, Mr. F. 

 Y. Theobald, who has charge of the work, from all quar- 

 ters of the globe, and Mr. Theobald has made a special 



