PREFACE TO BULLETIN. 



During the writer's investigations of extensive insect depredations 

 in the forests of West Virginia, from 1890 to 1902, he was forcibly 

 impressed with the importance of the forest-insect problem in any 

 future efforts toward the successful management of the forests of 

 this country, and was thus led to give special attention to the sub- 

 ject. It was soon realized that among the principal groups of insect 

 enemies of forest trees the scolytid bark and wood boring beetles 

 must occupy first rank, both in economic importance and in system- 

 atic interest. Subsequent investigations in West Virginia, in con- 

 nection with the work of the West Virginia Agricultural Experiment 

 Station, and in all of the principal forest regions of the country, in 

 connection with the work of the Bureau of Entomology, have served 

 to confirm these first impressions. 



In these investigations special efforts have been made to acquire 

 information on habits and seasonal history of the various species, 

 and other facts relating to them, and to collect an abundance of mate- 

 rial for systematic study — all to form a basis for conclusions in regard 

 to the principal enemies of American forests and practical methods 

 for their control. 



The large amount of material has been pretty thoroughly worked 

 over and identified, and synoptic tables and descriptions for the 

 greater part liave been completed for some time. Delay in publish- 

 ing the results of the systematic part of the investigations has seemed 

 necessary, in order that sufficient time might be given for the deter- 

 mination of taxonomic details as a basis for reliable conclusions in a 

 comprehensive treatment of the group as a whole, but with increas- 

 ing duties in the general work on forest insect investigations, and the 

 more and more limited time available for systematic work, it is realized 

 that these taxonomic studies can not be completed for many years. 



To avoid further delay in the publication of data of immediate 

 interest and importance, the writer has decided to postpone the dis- 

 cussion of tlie taxonomic and other subjects of a philosophical nature, 

 required for a completed monograph, and for the present to issue 

 separate contributions, each part to be restricted to one genus, or, at 



