LYMNEIDZ OF NORTH AMERICA. VII 
Also to the John Crerar Library, Chicago, and the Library of the 
University of Chicago, for assistance in the preparation of the bibliog- 
raphy. 
The author is under great obligations to the following persons 
who have generously placed at his disposal their collections and, in 
many cases, have also presented to the Chicago Academy of Sciences 
a large amount of material for investigation, for which he wishes to 
express his gratitude: 
Adams, Charles Christopher, Illinois State University. 
Allen, John A., Cleveland, Ohio. 
Armstrong, Edward H., Providence, R. I. 
Arnold, Ralph, U. S. Geol. Survey, Washington, D. C. 
Ashmun, E. H., Weiser, Idaho (deceased). 
Bain, H. Foster, Urbana, IIls. 
Baker, Mrs. Frank C., Chicago, III. 
Berry, S. Stillman, Stanford University, California. 
Brown, C. E., Milwaukee, Wis. 
Button, Fred L., Oakland, California. 
Calkins, W. W., Chicago, Ills. 
Cass, Charles L., Pacific Beach, Cal. 
Chase, Virginius H., Wady Petra, Ills. 
Clapp, George H., Pittsburg, Penn. 
Clarke, John M., Director, New York State Museum, Albany, N. Y. 
Cockerell, T. D. A., University of Colorado, Boulder, Colo. 
Conner, Charles H., Philadelphia, Penn. 
Danielss Il, EF. Wai Porte Indiana. 
Elrod, Morton J., University of Montana, Missoula, Mont. 
Ferriss, James H., Joliet, Ills. 
Forbes, S. A., Mlinote State Laboratory of Natural History, Urbana, Ills. 
Frierson, L. S., Frierson, La. 
Gannett, Henry, Washington, D. C. 
Gratacap, L. P., American Museum of Natural History, New York City. 
Greenicher, S., Milwaukee, Wis. 
Handwerk, J. H., Joliet, Ills. 
Hanna, G. Dallas, Lawrence, Kans. 
Hannibal, Harold, San Jose, Cal. 
Hart, Charles A., Illinois State Laboratory of Natural History, Urbana, Ills. 
Hemphill, Henry, San Diego, Cal. 
Henderson, John B., Jr., Washington, D. C. 
Henderson, Junius, University of Colorado, Boulder, Colo. 
Hinkley, Anson A., Du Bois, Ills. 
Hood, J. D., State Laboratory of Natural History, Urbana, Ills. 
Iseley, F. B., Tonkawa, Oklahoma. 
Johnson, Charles W., Curator, Boston Society of Natural History, Boston, 
Mass. 
Keep, Josiah, Mills College, Cal. 
Kirkland, Reynold J., Grand Rapids, Mich. 
Latchford, F. R., Ottawa, Ontario, Canada. 
