IV PREFACE. 



of the larger groups, sufficient justice has not been paid 

 to the frequent diversity observable. Certain small and 

 unimportant families have also been omitted ; it is believed, 

 without detriment to a work of this scope. 



Most authors regard the Hymeuoptera and equivalent 

 groups as "orders" rather than "suborders." When 

 the reader prefers, he might alter to suit his views. It 

 is not improbable that the Hexapoda, Arachnida and My- 

 riapoda are subclasses; hence, the Hymeuoptera, etc., 

 may be considered as orders, and then, for example, the 

 Hemiptera, Heteroptera and Lice (Pediculina and Mallo- 

 phaga) might be regarded as suborders of the grand 

 group Hemiptera. It matters little to the author, so long 

 as the fact (or what he believes to be the fact) be recog- 

 nized, that the Hexapods, Arachnids and Myriapods are 

 subdivisions of a class, and not separate classes equivalent 

 each to the Crustacea, for example. 



Salem, March, 1872. 



