PREFACE 



All teachers are agreed that the best results in the classroom are 

 secured only by the adoption of the best pedagogical methods, with 

 ready access to the necessary specimens and literature. Just what 

 these methods comprise, however, is, with many teachers, a matter of 

 opinion. Quot homines tot sententice, nevertheless the indulgent reader 

 may concede that an experience of over twenty years as a teacher of 

 economic entomology in agricultural colleges may warrant the voicing 

 of the author's conviction that instruction in this subject should con- 

 sist of (i) studies on the structure, metamorphosis, and bionomics of 

 insects, carried on both in the laboratory and in the field; (2) practice 

 in the classification and description of the more common insects in 

 their various stages; and (3) studies of the methods of control, with 

 practical exercises in the preparation and application of insecticides. 



Although several most excellent manuals on Economic Entomology 

 have been published in recent years, there seems to be a need for a 

 book providing the necessary information for the student in the class- 

 room, laboratory and field along the lines indicated above. 



This class-book, therefore, has been prepared to meet the needs of 

 the class-room instructor, and his needs have influenced the mode of 

 presentation of the subject material. It does not presume to take the 

 place of the invaluable and well-known works of Folsom, Comstock, 

 Slingerland and Crosby, and others; but rather, it aims to present such 

 material as will best help the student in acquiring a fair working knowl- 

 edge of the modern science of Economic Entomology. 



The treatment of many of the topics is necessarily limited, and the 

 keys for the identification of orders, families, and genera make no pre- 

 tensions to completeness. The descriptions of the species discussed in 

 Part III are stripped of all unnecessary verbiage so that all the essential 

 facts of the life-histories may be included in the space at the author's 

 disposal. 



