IV 



PAGE 



II. Prairie area near Loxa, Illinois, Station II 52 



III. Prairie area east of Charleston, Station III 55 



Description of the forest habitats and animals 56-66 



1. The Bates woods, Station IV 56 



2. The upland oak-hickory forest, Station IV, a 57 



3. Embarras valley and ravine slopes, forested by the oak-hickory 



association. Station IV, b 59 



4. Lowland or "second bottom," red oak-elm-sugar-maple-woodland 



association. Station IV, c 62 



5. Supplementary collections from the Bates woods. Station IV. . . . 65 



6. Small temporary stream in the south ravine. Station IV, a 65 



General characteristics of the gross environment 66-102 



1. Topography and soils of the State 66 



2. Climatic conditions 67 



3. Climatic centers of influence 69 



4. Relative humidity and evaporating power of the air 71 



5. Temperature relations in the open and in forests 83 



6. Soil moisture and its relation to vegetation 86 



7. Ventilation of land habitats 88 



8. The tree trunk as a habitat 91 



9. Prairie and Forest vegetation and animal life 91 



10. Sources and role of water used by prairie and forest animals.. 98 



Animal associations of the prairie and the forest 102-158 



I. Introduction 102 



11. The prairie association 103 



1. Swamp prairie association 103 



2. The Cottonwood community 105 



3. Swamp-grass association 107 



4. Low prairie association 108 



5. Upland prairie association 10j9 



6. The tiolidago community 109 



7. Dry prairie grass association -. Ill 



8. A milkweed community 112 



III. Relation of prairie animals to their environment 113 



1. The black soil prairie community 114 



2. The prairie vegetation community 117 



3. Interrelations within the prairie association 119 



IV. The forest associations 122 



1. Introduction 122 



2. Dry upland (Quercus ana Cnrya) forest association 124 



3. Artificial glade community in lowland forest 125 



4. Humid lowland (hard maple and red oak) forest asso- 



ciation 126 



5. Animal association of a temporary stream 127 



