To Dr. H. A. Gleason I am under deep obligation for guidance in 

 the field, for various information, for reading the manuscript, and for 

 help of other kinds. I am grateful to Mr. C. A. Hart, who has helped 

 me in many ways. Dr. F. C. Gates has allowed the use of some of 

 his field records. Dr. M. M. Ellis has read part of the manuscript 

 Mr. G. C. McFadden, of Havana, has furnished information concern- 

 ing the topography of the valley. Professor T. E. Savage has fur- 

 nished maps of the regions studied. Mr. F. E. Wood has given in- 

 formation concerning the mammals. Mr. Herman Douthitt has 

 contributed toward the collections. To each of these gentlemen I de- 

 sire to express my thanks. 



The determination of the animal species has involved the labor of 

 many persons. The bulk of the insect determinations are divided 

 about equally between Mr. Hart, of the State Laboratory of Natural 

 History, and the writer. The large insect collection of this Labora- 

 tory, containing, as it does, many previous collections by Mr. Hart 

 from the sand regions, has been of most material assistance. The 

 other determinations have been made by the following gentlemen : 

 Professor T. D. A. Cockerell, University of Colorado ; Mr. James H. 

 Emerton, Boston, Mass. ; Professor J. W. Folsom, University of 

 Illinois; Mr. A. A. Girault, Brisbane, Australia; Mr. J. D. Hood, 

 U. S. Biological Survey ; Dr. George W. Peckham, Milwaukee, Wis. ; 

 Professor Charles Robertson, Carlinville, 111. ; Mr. S. A. Rohwer, 

 U. S. National Museum; Dr. Henry Skinner, Academy of Natural 

 Sciences of Philadelphia ; Dr. Maurice C. Tanquary, now on the 

 scientific staff of the Crocker Land Expedition ; Mr. A. B. Wolcott, 

 Field Museum of Natural History; and Mr. James Zetek, entomolo- 

 gist to the Sanitary Commission of the Panama Canal Zone. These 

 determinations are credited separately in the annotated list. 



General Relations oe the Ieeinois Sand Regions 



general description oe the locality 



The locality studied is in central Illinois, in Mason county, in the 

 valley of the Illinois River. There are two vegetation types in Illi- 

 nois, prairie and forest. In the northern parts of the state the forests 

 are found in belts along the streams, the large rivers having the broad- 

 est forest belts. The sand areas of the Illinois River, though located 

 in a wide forest belt, are characterized chiefly by a prairie vegetation, 

 due to a local difference in soil. As will be shown later, the sand 

 prairie differs in many respects from the richer black-soil prairie of 



