INTRODUCTION 15 



J. K. Alter, Wayland; *B. H. Bailey, Cedar Rapids; Paul Bau- 

 man, Melvin; Virgil Bearden, Thayer; Merrill Deal, Waukon; H. 

 R. Dill, Iowa City; Kenneth Dunlop, Jefferson; Marcus Fiene, 

 Ocheyedan; Joe Gibson, Corning; Porter Green, Garrison; San- 

 ford Griswold, Charles City; W. P. Kubichek, Iowa City; J. R. 

 Martin, Tama; Marion Mincks, Ottumwa; Henry Schroeder, Yin- 

 ton; J. A. Spurrell, Wall Lake; A. 0. Thomas, Iowa City. 



Specimens have been examined in the Museum of the State Uni- 

 versity of Iowa, the Coe College Museum, the Grinnell College Mu- 

 seum, and the Iowa State Museum at Des Moines. The sources of 

 other material and information are given in the text. 



In addition, data of various kinds have been obtained from 

 farmers, hunters, and trappers while the county auditors of the 

 various -counties visited have given information and notes on 

 bounties. All have been uniformly courteous and sympathetic. 



Determinations of specimens have been made and verified by 

 officials of the United States Biological Survey through the cour- 

 tesy of Mr. E. W. Nelson, Chief of the Survey. Various points 

 of difficulty have, from time to time, been referred to workers in 

 the Survey, and the response has always been prompt and grat- 

 ifying. Certain of the figures herein published have also been 

 furnished by the Division of Publications, United States Depart- 

 ment of Agriculture. 



Mr. Frank C. Pellett of Atlantic has furnished notes, specimens, 

 and data relating to some of the forms discussed ; and several of the 

 photographs herein included are the result of his work. 



Miss Jane E. Roberts, Librarian at the State University of 

 Iowa, has made it possible for me to have access to various books 

 and papers not found in the University Library, but which were 

 essential to the prosecution of this work. 



Especial thanks are due Professors C. C. Nutting and H. F. 

 Wickham, of the Department of Zoology, State University of Iowa, 

 for helpful suggestions and criticism during the preparation of 

 this paper. 



Dr. James H. Lees, Assistant State Geologist, has offered sugges- 

 tions and granted many courtesies. 



To Professor G. F. Kay, Director of the Iowa Geological Sur- 

 vey, I desire to express my appreciation for having made possible 

 this bulletin and for continued encouragement and interest during 

 its preparation. 



*Deceased. 



