Vll 



PAGE 



Ratios of Frequency and Preference 321 



Ratios of Frequency, most Abundant Birds, Indiana line to Quincy 



(Table IX) 324 



Coefficients of Preference : 



All Birds, Indiana line to Quincy (Table X) 325 



Nine most Abundant Birds, Indiana line to Quincy (Table XI) 325-328 



Data of Tables; Classification by Crops (Table XII) 329-332 



Conclusion 332 



List of Birds identified, Indiana line to Quincy ,334 



ARTICLE X. THE ORIBATOIDEA OF ILLINOIS. BY HENRY E. 



EWING. (3 Plates; 5 Text Figures.) September 25, 1909 . .337-389 



Introduction 337 



Methods 338 



External Anatomy 339 



Internal Anatomy 341 



Life History 343 



Habits 344 



Taxonomy of the higher Groups 345 



Key to Families 348 



Keys to Genera: 



Oribatidce 349 



Nothrida; 349 



Hoplodermida; 351 



Descriptions of Species: 



Family Oribatidce 351 



Genus Oribatella 352 



Key to Species 352 



Genus Oribata 353 



Key to Species 3 54 



Family Nothrida; - 364 



Genus Liacarus 365 



Key to Species ! 365 



Genus Notaspis 367 



Key to Species 367 



Genus Tegeocranus 370 



Key to Species 370 



Genus Damams 371 



Key to Species 371 



Genus Hermannia 373 



Genus Hypochthonins 374 



Family Hoplodermida; 375 



Genus Hoploderma 375 



Key to Species 375 



Genus Phthiracarus 377 



Key to Species 377 



A List of the Known North American Species of Oribatoidea 379 



Explanation of Plates 389 



