82 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 10 



paths marked out by ancient trails and where a need has arisen for the 

 earnest consideration of a town-planning system. Our further prog- 

 ress must be based upon principles that modern experience has indi- 

 cated as being fundamental to a rightly conceived and an orderly 

 development of future investigation. 



Insect behaviour constitutes the basis of applied entomology and, 

 while that fact may now be more generally realized, I feel that if the 

 point of view such a conception implies were constantly borne in mind 

 we should be able to approach the solution of our problems in a man- 

 ner that would lead to even greater success than has already crowned 

 our efforts. 



Action is the result of the manner in which man experiences. So, 

 also, the reaction of an insect to its environment finds expression in 

 the behaviour of the insect. Behaviour, as Jennings has stated, "is 

 merely a collective name for the most obvious and most easily studied 

 of the processes of the organism, and it is clear that these processes are 

 closely connected with, and are indeed outgrowths from, the more 

 recondite internal processes. " Stated briefly in another way, behaviour 

 consists in the adaptation of the insect to its environment. Anything 

 injurious to the insect causes changes in its behaviour and conversely 

 anything advantageous to it produces a change in the behaviour. Of 

 the factors which regulate behaviour in insects, as in other organisms, 

 internal conditions and processes are effective no less than external, 

 and both may be, and generally are, the product of environment. 

 Further, to be effective the external stimulus of the environment, 

 whether it be physical or biological, must produce a change in the 

 physiological state of the organism. 



The activities of injurious insects which furnish the problems of 

 applied entomology are more pronounced in countries where, for 

 various reasons, the stability of the physical and biological environ- 

 ment is changed. This affords the reply to a question often asked, 

 namely, why entomologists are faced with more problems in newer 

 countries, such as our x)wn, than in older countries? One of the chief 

 causes affecting the stability of the environment and consequently the 

 activities of the insects in such countries as the United States and 

 Canada is the extension and development of agriculture and of agri- 

 cultural areas. In countries of an older civilization the environmental 

 conditions, particularly the agricultural conditions, are fairly stable 

 by reason of the long period of their gradual development. In such 

 countries we find a conservative type of husbandry with which careful 

 rotations of crops and a fairly intensive system of cultivation are 

 associated. In the newer countries, not only has widespread develop- 

 ment within comparatively brief periods of time been responsible for 



