ECOLOGY OP ISLE ROYALB. 419 



as it was apparently the most abundant form, or to M. suhtilatus. The 

 last bat seen on the wing by Peet was about Washington Harbor, 

 September 15. A small dark colored bat was startled from a loose 

 projecting rock on the face of the cliff on the jack pine ridge (I, 5). 

 A few days later one was flushed at nearly the same place. A bat 

 flew into the Light-house at Rock Harbor but was not secured. Bats 

 were also seen at camp on Siskowit Bay (V, 3). One specimen was 

 taken in 1904 by Peet at Washington Harbor. 



Two specimens were received from Michael Hollinger, who secured 

 them November 30, 1904, at the Club House (I, '04). These evidently 

 hibernated in the cellar as they were found on wing in the house after 

 a fire had been built in the cellar. 



This species had previously been collected from Isle Royale by B. A. 

 Hoops, No. 5319, U. S. Nat. Mus. (Allen, '93, p. 80). Allen also 

 records three specimens from Grosse Isle, Mich., collected by Rev. C. 

 Fox, (No. 5500, 5501, 5505 U. S. N. M.) ; another specimen (No. 5354) 

 was taken by S. P. Baii-d on the Detroit River. Miller in his revision 

 of the family Vespertilimiidae (1897) examined no Michigan specimens 

 of this species. 



Ecological Notes. — On account of the difficulties in determining bats, 

 their life histories are much confused. This species Todd found hiber- 

 nating in the caves of Pennsylvania (Rhoads, '02, p. 208), and the 

 November specimens show that it hibernates on Isle Royale. 



Geographic Range. This bat has the most extensive geographic range 

 of any of the mammals on Isle Royale. The typical form ranges from 

 southern Alaska east of the Rocky Mountains throughout North 

 America, yet in spite of its powers of locomotion, two local forms are 

 known; longicrus ranges from Puget Sound and Wyoming south to 

 northern Mexico and Lower California, and alascensis which is restrict- 

 ed to the northern British Columbia and the coast region of southern 

 Alaska. The differentiation of "these forms, in the case of a flying 

 mammal, suggests that the mountains form to some degree a true 

 barrier within the range of this species. 



15. Vespertilio fuscus Beauv. Brown Bat. One specimen was taken 

 at Washington Harbor (I, '04) on August 19. 



Ecological Notes. — Fisher (Merriam, '86, p. 184) remarks that this 

 species is the last to appear in the evening and that they are "parti- 

 cularly fond of fields well surrounded by trees." It is an abundant 

 species about human habitations and hibernates. 



Oeographic Range. — The typical form of this species ranges from 

 California over the United States except Florida, and northward into 

 British Columbia and Ontario. There are eight forms of the species 

 ranging over the West Indies and south into Guatemala and Costa 

 Rica. 



V. References. 



Adams, Chas. 0. 



1905. The Postglacial Dispersal of the North American Biota. Biol. 

 Bull., 9, pp. 53-71. 

 Allen, H. 



1893. A Monograph of the Bats of North America. Bull. U. S. Nat. 

 Mus., No. 43. 



