12 Mosquitoes and 
but as we have not the disease in this country the mosquitoes are 
harmless with us. 
The bite of Anopheles is inflicted almost exclusively at dusk or 
during the night, but the species will bite during the day if 
disturbed. 
Mosquitoes and Yellow Fever. —The ravages of yellow 
fever in South and Central America, and the part played by the 
disease in causing the failure of the early attempts to construct 
the Panama Canal, are well known, as is the fact that the disease 
/ \ 
/ \ 
Fig. 5.— Stegomyici fasciata, F. (oe Aedes calopus, Mg.) ?. X 4. 
The only carrier of yellow fever. 
is carried by a mosquito. The mosquito theory was first put 
forward by Dr. Finlay of Havana so long ago as 1881, and he 
adduced some strong evidence in support of his views ; but definite 
and conclusive proof was not obtained until 1900, when the United 
States Army Commission, under the direction of Dr. Eeed, solved 
the problem in Cuba. A number of subsequent investigations 
have been made, with confirmatory results, so that it may now be 
stated with certainty that Yellow Fever is spread only through 
the agency of one particular kind of mosquito, the species known 
to science as Stegomyia fasciata or Aedes calopus. Search for the 
parasite actually causing the disease has so far been unsuccessful, 
