6 PREFACE. 



It is believed that by means of these insertions the reader in 

 search of a general account of an insect or other subject will be 

 saved much time, being able to see at a glance and select the more 

 important accounts. 



What has been said ai)plies to the General Index. A word of 

 explanation is due in regard to the Plant Index. The aim has been 

 to itemize the more important food plants of an insect, and unim- 

 portant mention of a food plant is not as a rule recognized, since 

 such items are practically of- no value and wo aid increase the size 

 of the Index far beyond its present dimensions without a cor- 

 responding increase in its usefulness. Thus "bean " is not indexed 

 every time that injury by the bean weevil is referred to, nor " hop " 

 whenever the hop louse is mentioned, but the reader is referred to 

 the General Index where full lists of references are given. Reviews 

 and other notices of works are indexed under the subjects treated of 

 and not under the name of the authors. References to agricultural 

 experiment stations are entered under the general heading ' ' Experi- 

 ment Stations " and not under authors or States. 



L. O. Howard. 



