10 INTRODUCTORY. 



The field party left Ann Arbor, July 11, after three weeks of unfortunate 

 and unavoidable delay, and explored the Porcupine Mountains until August 

 13. These mountains rise rather abruptly from the south shore of Lake 

 Superior, and in a succession of ridges reach the height of about 1400 feet, 

 at about two miles in the interior. The entire region is inhabited only by 

 scattered trappers, and the forests are practically in their original condition. 



From the Porcupines (August 13), the party went to Isle Royale, about 

 60 miles northwest of Houghton, where they made a hasty examination of 

 the lower end of the island, the party remaining here until September 5. The 

 lateness of the season furnished an excellent opportunity to make obser- 

 vations on the fall migration of the birds, and these notes are of peculiar 

 interest on account of the insular location. 



After the return of the party from the field, the preparation of the report 

 was begun at once and has been carried on as rapidly as circumstances 

 would permit. As the volunteer members of the party have been busy 

 with other duties the preparation of the reports, in some cases, represents 

 considerable sacrifice on their part. In particular this has been the case 

 with Mr. Ruthven, upon whom naturally fell the* heaviest burden. 



A very pleasant feature in connection with the preparation of this report 

 has been the generous cooperation of a large number of naturalists. In 

 behalf of the University Museum I wish to acknowledge our indebtedness 

 to these persons, who have, in addition to furnishing information concerning 

 the collections, and the determination of specimens, in some cases con- 

 tributed papers. The following list will show by whom the specimens 

 have been determined. 



Prof. Bruce Fink, Iowa College, Grinnell, Iowa. Lichens. 



Dr. C. A. Davis, University of Michigan. Higher plants. 



Mr. S. Alexander, Ann Arbor, Mich. Higher plants. 



Dr. J. P. Moore, University of Pennsylvania, Philadelphia. Leeches. 



Mr. Nathan Banks, U. S. Dept. of Agriculture, Washington. Spiders. 



Mr. E. B. Williamson, Bluffton, Ind. Odonata. 



Mr. J. R. De la Torre Bueno, New York. -Hemiptera. 



Mr. A. P. Morse, Wellesley College, Wellesley, Mass. Orthoptera. 



Prof. A. J. Snyder, Springfield, Idaho. Lepidoptera. 



Dr. W. M. Wheeler, American Museum Natural History, N. Y. Ants. 



Mr. Bryant Walker, Detroit, Mich. Molluscs. 



Dr. S. E. Meek, Field Columbian Museum, Chicago. Fish. 



Dr. L. Stejneger, Smithsonian Institution, Washington. Amphibia. 



Mr. Robert Ridgway, Smithsonian Institution, Washington. Birds. 



Mr. H. C. Oberholser, Smithsonian Institution, Washington. Birds. 



Dr. C. Hart Merriam, Biological Survey, U. S. Dept. Agriculture, Washing- 

 ton. Mammals. 



Mr. W. H. Osgood, Biological Survey, U. S. Dept. Agriculture, Washing- 

 ton. Mammals. 



Dr. Glover M. Allen, Boston Soc. Nat. History, Boston. Mammals. 



This is also an appropriate place to express our obligations to Dr. A. C. 

 Lane, State Geologist of Michigan, who furnished the party with maps and 

 other information on Isle Royale and the Porcupine Mountains. 



We are indebted to Mr. John F. Nellist for the contour map showing 

 the location of the stations in the Porcupine Mountains, which he adapted 

 from the map furnished by Dr. Lane. 



