PREFACE. 9 



To entomologists who fool an interest in the causes of insect dis- 

 eases and who wish to bo able to judge with some satisfaction the 

 work that has boon and is being done on insect diseases this bulletin 

 will be of special interest. It is believed that by the learning of the 

 mistakes made by workers on bee diseases, and by the learning of 

 the causes for sucli mistakes, the careful reader will be enabled to 

 judge more accurately the value of the various reports that appear 

 on the diseases of insects. 



The a it nous. 



