INTRODUCTORY. 



Insect injury to agricultural products amounts each year to 

 millions of dollars, and, as a whole, shows a tendency to increase 

 rather than otherwise. It is not only the actual devouring of 

 plant tissue that causes loss ; the effect upon the product may 

 be to reduce its grade, or make it more or less unsalable and 

 unprofitable. In the competition for markets, the grower of 

 the best will always have an advantage ; first-class fruits and 

 vegetables rarely fail to bring some profit, where low-grade 

 products cannot be sold at any price ; and no fruit that is 

 wormy, defaced, or otherwise injured by insects ever ranks as 

 first-class. 



Progressive farmers have long been aware of this, and the 

 science of economic entomology has grown up in response to 

 their demands for information concerning insect depredation and 

 for means of protection against it. It is a science far from sys- 

 tematized as yet ; made up of fragments published here, there, 

 and everywhere, rarely complete in themselves and often con- 

 tradictory as to the remedial measures suggested. There have 

 been efforts, more or less successful, to compile books of infor- 

 mation concerning the insects attacking certain crops or kinds 

 of crops ; but there is not now in existence any work which 

 gives the agriculturist and student of economic entomology that 

 basic knowledge that enables him to recognize the nature of the 

 insect he finds causing injury, or makes it possible to decide 

 what sort of remedies should be applied. In other words, the 

 underlying facts upon which the scientific application of remedial 

 or preventive measures is based are not accessible to the very 

 class that most needs them. 



In this book an attempt is made to present these matters com- 

 pletely enough to give a foundation upon which further informa- 

 tion may be added ; for whatever changes may occur in our 



XI 



