PEEFACE. 21 



The extent of the present use of Paris Green and 

 arsenical preparations in the United States is not 

 generally known in the absence of proper statistics. 

 Were these published, public attention would pro- 

 bably be aroused to the danger of the situation. 



With every other field for human inquiry and 

 action, the study of even such a small assemblage of 

 insects as the Noctuidce touches a number of other 

 interests which at first sight appear remote. But 

 the Noctuidse of North America include at least two 

 species of insects injurious to agriculture wliich, in 

 this respect, are among the most important of insect 

 enemies to man on our continent. Beside Hel'io- 

 l)hila TInipuncta, the Army Worm, and Aletia Arg'il- 

 lacea, there are a certain number of species of cut- 

 worms belonging to the genera Agrotis and Hadena 

 which attack various field- and garden-crops. Out- 

 side of these are tlie great bulk of the species of 

 Noctuidce which feed on weeds and plants not of 

 any particular economic importance. There are 

 plenty of them to reward the labours of the collector, 

 and to puzzle the philosophers who believe that 

 every thing has its use, and that man himself is the 

 pivot about which all creation turns. 



I cannot close this Preface without thanking a 

 number of correspondents who have sent me 

 material during the last twenty- five years from 

 various points of the United States and Canada. 

 I owe almost all my knowledge of Western Noc- 

 tuidse to the collections received from Mr. Henry 

 Edwards, Mr. James Behrens, Prof. E. H. Snow, 

 Mr. Theo. L. Mead, and Mr. Berthold Neumoegen. 



