PREFACE 



For nearly twenty years Professor Slingerland, as Assistant 

 Entomologist of the Cornell University Agricultural Experiment 

 Station, devoted the greater part of his time to studying the 

 insect problems encountered by the fruit-growers of New York 

 State. The results of some of these studies were published as 

 bulletins of the Station, but a large amount of material remained 

 unpublished. It was the idea of making this material available 

 to other workers and at the same time bringing together in con- 

 nected form all the more important known facts concerning the 

 insect enemies of our deciduous fruits, that led Professor Slinger- 

 land in the fall of 1908 to begin writing this book. During the 

 few remaining months of his life he worked rapidly, and in spite 

 of failing health wrote accounts of more than one-half of the 

 apple insects and some others, mostly scale insects. 



After Professor Slingerland's death in March, 1909, I collected 

 and preserved the manuscript, thinking that it might be possible 

 to publish it without much additional work. While the treat- 

 ment of each insect was complete in itself, the whole w^as so dis- 

 connected that this plan had to be abandoned. Accordingly, in 

 the summer of 1910 I undertook the task of completing the book, 

 following Professor Slingerland's outline. In doing so, I have 

 made free use of his unpublished notes, and most of tlie illustra- 

 tions are from his })liotographs. 



We have attempted to treat only the more important insects 

 injurious to deciduous fruits ; many of the minor pests have been 

 omitted altogether. In each case the aim has been to give, in as 

 concise form as possible, the main facts relating to the distribu- 

 tion, life-history, and habits of the insect, the nature and extent 



