cxliv Proceedings of the Asiatic Society of Bengal. [N.S., XV, 
active beetles will be able to find food, and the species as a 
whole will decline in numbers. If on the other hand the point 
of sensory contact lies within the normal beetle’s range in 
space, then the species will increase up to the limit of the food- 
supply. There will in fact be a correlation between an insect’s 
range in space, its sensory threshold, and the period of its life- 
cycle. Moreover, we can use our model in considering the 
practical measures to be adopted against insects or other 
noxious animals; for if the model is made on sound lines, we 
reason is a very simple one: I had to. 
For many years insects have been studied far too much 
as lc organisms. Their external form and the bare facts 
some particular name to an insect. Certainly the wrangles, 
though undignified, were amusing, and of course morphological 
and life-history studies are valuable—up to a point. But it is 
nature of the relation between a parasite and its host, a nox- 
ious organism and its victim—has, in the case of insects, been 
almost entirely neglected. And this is in no way an isolated 
case. For in all the more difficult problems of Applied Zoology, 
di 
man; an we are ever to attain to an effective control of 
noxious organisms, and in particular to an effective and eco- 
nomical control of insects based on some real understanding 
we must frankly recognize that entomology alone, as ordinari- 
ly understood, is unequal to the task. It has indeed proved 
itself unequal. The war has done many things. It has let the cold 
