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PREFACE 



This work was Ijc^uii a number of years ago by the writer studying 

 various insects deprt^tlating on shade trees, and from that it was very 

 natural to give attention to those affecting forest trees. It assembles in one 

 volume the results of our studies for a scries of years, together with a 

 summary of the more important literature relating to the subject. It is not 

 e.vpected that this memoir will supersede the exceedingly valuable work by 

 Dr Packard on Forest and S/iadc 'free Insects, 5th Rejjort of the United 

 States Entomological Commission, l)ut rather that it will be supplementary 

 thereto. It is hoped that the arrangement adopted will facilitate the identi- 

 fication of the different species and aid materially in making the information 

 accessible to the general public. The writer at this time wishes to acknowl- 

 edge his indebtedness to the assistants who ha\e been associated with him 

 during the past si.x years, all of whom have aided more or less in the 

 preparation of this work. Particular mention shoukl lie made of the work 

 of Mr D. B. Young, now assistant entomologist, who during the last three 

 years, by collecting and otherwise, has secured much valuable data which 

 has been incorporated in this work. Through the courtesy of Dr L. O. 

 Howard, Chief of the Bureau of Entomology, United States Department 

 of Agriculture, a number of species were kindly determined by Drs Hop- 

 kins and Ashmead. The former named most of the bark borers or .Scoly- 

 tids and also generously gave the writer the benefit of his extended 

 experience in the study of forest insects. Dr. Ashmead is res])onsible for 

 the determination of most of the parasitic 1 lynienoptera, a grou|) in which 

 he is a well recognized authority. The value of the work is also greatly 

 enhanced by the large series of original drawings by Mr L. H. Joutel 

 of New York. 



This publication is essentially practical or economic in nature, and as 

 such, gives special attention to the more injurious species depredating 

 on shade and forest trees. A .somewhat radical, though we hope none 

 the less valuable, departure from the ordinar\- treatment in economic 



