20 INSECTS AND MAN 



that have been and, to a limited extent, are still used as 

 drugs, and we obtain quite a respectable total on the credit 

 side, though hardly a balance, it must be admitted, even 

 when we include an enormous number of predatory and 

 parasitic insects, which, by waging ceaseless warfare on 

 their harmful relatives, serve to keep them in check. 



That the struggle for supremacy between insects and 

 man is a very real one the world over it is hoped that 

 these pages will show. 



In the words of a celebrated American entomologist : 

 ' Man is but one of the forms of life struggling for existence, 

 at continual warfare with surrounding forms, but by virtue 

 of his surpassing intelligence itself as gradually evolved 

 as have been the physical characteristics of any given 

 species he has overrun the earth, has accommodated him- 

 self to the most unnatural environments ; he has dominated 

 all other species in nature ; he has turned to his own uses 

 and encouraged or hastened the evolution of species useful 

 to him or of useful qualities in such species ; he has wiped 

 out of existence certain inimical forms and is gaining the 

 control of others. He is the dominant type, and types 

 whose existence or methods of life are opposed to his 

 interests are being pushed to the wall. It is the culmina- 

 tion of a history which has many times repeated itself in 

 past ages. The struggle of other forms of life to accommo- 

 date themselves to the conditions brought about by the 

 rapid development of the dominant type is one of the 

 interesting fields of study open to the biologist to-day. It 

 would seem as if in man's efforts to make the face of the 

 earth his own, all the complicated elements of life were 

 arrayed against him ; and the great and ultimate result of 

 the labour of the biologist in his study of the relations of 

 the different forms of life, and the laws which govern their 

 development, will be to bring about the absolute control 

 of all other life by man. Thus, it is not only the economic 

 worker who looks for result of a practical kind from his 



