Vll 



PAOE 



Ratios of Frequency and Preference 321 



Ratios of Frcfiuencv, most Abundant Birds. Indiana line to Ouincy 



(Table IX) " .524 



Coefficients of Preference: 



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



Nine most Abundant Birds. Indiana line to Ouincy (Talile XI) 32.S-.328 



Data of Tables; Classification by Crops (Table XII) 320-332 



Conclusion ^i^ 



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 Cienera: 



Oribatida 349 



Nothridcc 349 



Hoplodcrmidcc 3 51 



Descriptions of Species; 



Family Oribatidcs 351 



Genus Oribatella 352 



Key to Species 352 



Genvis Oribata 353 



Key to Species 354 



Family Xothridce 364 



Genus Liacarus 365 



Key to Species 365 



Genus Notaspis 367 



Key to Species 367 



Genus Tc^cocranus 370 



Key to Species 370 



Genus Damicits 371 



Key to Species 371 



Genus Hermannia 373 



Genus Hypochthonius 374 



Family Hoplodermida; 3 7 5 



Genus Hoploderma '75 



Key to Species 37 5 



Genus Phthiracarns 37 7 



Key to Species 3 7 7 



A List of the Known North American Species of Oribatoidea 379 



Explanation of Plates 389 



