72 Applied Entomology 
instance of the newly opened Panama Canal. The French failed in 
that project owing to the enormous toll of human lives entailed through 
yellow fever, and to financial disaster. The toilers, from the engineers 
and doctors to the coolies, were afflicted with the dreaded disease. It 
is stated that out of 36 nurses brought over at the same time only 
12 survived. During one month nine members of the medical staff* of 
a single hospital succumbed. Out of 18 French engineers who were 
brought over together, with the exception of one all died from yellow 
fever within one month of their arrival (Doane, 1910, p. 136). When 
the U. S. Government took up the work they realised that neither 
money nor engineering skill was of any avail unless immunity from 
yellow fever could be attained. All areas of standing Avater in the . 
immediate neighbourhood of the Canal zone Avere filled up. Labourers 
Avere enforced to live in mosquito proof buildings in order to escape 
being bitten by mosquitoes. To-day the Avorkmen can even sit 
outside their houses in the evenings Avithout being sheltered behind 
gauze screens, so effectually have mosquitoes been exterminated (Gossard, 
1909, p. 320). It may be truly said that mosquitoes were the greatest 
problem in the cutting of the Panama Canal. In the year 1900 in 
Itidia 4,919.000 people died from malaria and unclassified fevers. 
There is every reason to believe that the majority succumbed from the 
direct or indirect effects of mosquito bites. Recently mosquito surveys 
have been initiated in India and the scope and utility of the Sanitation 
Department extended. It is to be hoped that the Government of 
India at last realises the paramount importance of such Avork, and the 
futility of attempting to govern peoples successfully so long as the bulk 
of their members suffer from preventable disease, and lack of adequate 
sanitary measures. 
III. Agncultural Entomology. 
It is, however, in connection Avith agricultural entomology that 
I propose to devote the greater part of this article. Insects affecting 
agriculture present to us an extraordinary divei'sit}^ of problems. If 
phytophagous insects Avere able to multiply in accordance Avith their 
natural powers of reproduction, they would be able in a feAV years to 
destroy the greater part of terrestrial vegetation. Fortunately there 
are a number of controlling agencies which effectually restrict the 
multiplication of such insects. Among these various factors are cli¬ 
matic conditions, insectivorous birds, scarcity of food supply, fungi 
and other pathogenic organisms. The most important, hoAvever, are 
