vi PREFACE 



In the following pages I have considered few of the details 

 which may be found in many other carefully prepared vol- 

 umes, but have rather attempted to avoid, as consistently as 

 possible, matters not directly necessary for a brief considera- 

 tion of insects as they affect human welfare. 



Most of the material contained in the chapter on Insects 

 and Public Health appeared in the Scientific Monthly, and 

 in its recast and revised form is reprinted with their kind 

 permission. The illustrations have come from several sources, 

 the photographs almost entirely from negatives made by the 

 author; of the maps, charts, etc., some have been made es- 

 pecially for the present book and others are redrawn or 

 modified from various authors. 



Owing to changes in nomenclature during the past few 

 years, many of our common insects now have different Latin 

 names. All of these changes have not been made in the 

 present book, as the author feels that they should become 

 well established before they are presented to the non-expert 

 reader. 



CHARLES THOMAS BRUES 



BUSSEY INSTITUTION 



HARVAKD UNIVERSITY 

 February, 1919 



