IV PREFACE. 



the present work even if it were possible to describe all of 

 our species. 



Although much pains has been taken to render easy the 

 classification of specimens, an effort has been made to give 

 the mere determination of the names of insects a very sub- 

 ordinate place. The groups of insects have been fully char- 

 acterized, so that their relative affinities may be learned ; 

 and much space has been given to accounts of the habits 

 and transformations of the forms described. As the needs 

 of agricultural students have been kept constantly in view, 

 those species that are of economic importance have been 

 described as fully as practicable, and particular attention has 

 been given to descriptions of the methods of destroying 

 those that are noxious, or of preventing their ravages. 



An effort has been made to simplify the study of in- 

 sects as much as possible without sacrificing accuracy in the 

 descriptions. Only such morphological terms have been 

 used as were necessary to accomplish the object of the book 

 in a satisfactory manner. And so far as possible a uniform 

 nomenclature has been used for all orders of insects. The 

 fact that writers on each order of insects have a peculiar 

 nomenclature has been a serious obstacle to the progress of 

 entomology ; this is especially true as regards the nomen- 

 clature of the wing-veins. It has been necessary for the 

 student in passing from the study of one order of insects 'to 

 that of another to learn a new set of terms ; and in many 

 cases writers on a single family have a peculiar nomenclature. 



The present writer has endeavored to remove this 

 obstacle by making a serious study of the homologies of the 

 wing-veins, and by applying the same term throughout the 

 work to homologous veins. The result is that the student 

 is required to learn only one set of terms ; and in applying 

 these terms there will be brought to his attention'in a forci- 

 ble manner the peculiar modifications of structure charac- 

 teristic of each order of insects. Heretofore, with a differ- 

 ent nomenclature for the wing-veins of each order such a 



