CONTENTS 



Letter of Transmittal iii 



The Board of Regents iv 



Part I. General. 



Economic Importance of the Collembola 3 



General Characters of the Collembola 5 



Relationships of the Collembola 9 



Collecting and Preserving Collembola 13 



Literature 15 



Part IL Systematic. 



Terms Used 23 



Keys for the Determination of Orders, Families, Gen- 

 era, etc 25 



Order Collembola 25 



Family Sminthuridae 25 



Genus Papirius 26 



" Sminthurus 27 



Family Entomobryidae 29 



Genus Orchesella 30 



" ISOTOMA 31 



" Entomobrya 33 



" tomocerus 35 



" Cyphodeirus 35 



" Seira 35 



" Lepidocyrtus 36 



Family Poduridae 37 



Genus Achorutes 38 



" Podura 39 



Xenylla 40 



" Friesia 40 



