CONTENTS. 



Habits and economic importance 5 



Structural characteristics 6 



Transformations " 



Previous work on species occurring in tlie United States 7 



Occurrence of European species in tlie United States 8 



Genera of the Tyroglyphidai - 9 



Table of the genera 9 



Genus Histiostoma 10 



Table of the species 10 



Genus Glyciphagus 12 



Genus Tyroglyphus 13 



Table of the species 13 



Genus Rhizoglyphus 1^ 



Table of the species 19 



Genus Monieziella - , 23 



Table of the species 23 



Genus Carpoglyphus 24 



Genus Trichotarsus 25 



Bibliography 26 



Index 29 



3 



