AMERICAN BATS OF THE GENERA MYOTIS AND PIZONYX 65 



enlarged. The pelage is shorter and not so glossy (on account of the 

 shorter glistening tips of the long hairs) and the skull is less flat- 

 tened and with a slightly more upturned muzzle. The ears are 

 thinner and narrower and usually less heavily pigmented. All these 

 differences are, of course, best appreciable on direct comparison. 



Very little is recorded concerning the natural history of Myotis 

 yvmmnensis. It is probably less of a forest haunter than Myotis 

 lucifuffus, preferring more open country with scattered tree growth, 

 though representatives of the two species occur together on the 

 Pacific coast, as well as in Montana and elsewhere. Mrs. Grinnell 

 (1918) records a large breeding colony that frequented the old ruined 

 buildings of Fort Tejon, Kern County, Calif. The adult males ap- 

 parently leave the colony when the young are born, and during 

 summer they may wander up to a considerable altitude in the open 

 woods of the dry mountain country. In the San Bernardino Moun- 

 tains, Calif., Mrs. Grinnell notes the capture of a male at 8,500 feet 

 elevation, and another was taken at 11,000 feet on the east slope of 

 Mount Whitney, Calif., along a small watercourse at the limit of tree 

 growth (G. M. Allen, 1919). A. B. Howell (1920) recounts the dis- 

 cover}^ of a large colony that frequented an abandoned mine tunnel 

 in California. A single young is the rule, and the breeding season is 

 early, at least in Texas, where on May 26, at Del Rio, Gaut found a 

 colony with young clinging to the old ones (Bailey, 1905). 



Of the geographical races into which Myotis yimumeTisis is divided 

 the most widespread is a dull-brownish form occupying a consider- 

 able area of the interior from at least western Montana south through 

 central California. In the humid coastal area from the central part 

 of California into Washington and southern British Columbia this 

 color becomes considerably darker, and again, in the desert country 

 of southeastern California, Arizona, and parts of Texas it changes 

 to an extreme of pallor. In the southern part of the Mexican high- 

 lands, again, there is a dark-brown race, the limits of whose distribu- 

 tion are yet undetermined. Throughout this range, however, there 

 is very little variation in size, a character which, together with its 

 dull, short pelage and narrow-tipped ears, will usually serve to 

 distinguish Myotis yumanensis from Myotis lucifugus where the two 

 species occur together. 



MYOTIS YUMANENSIS YUMANENSIS (H. Allen) 



Vespertilio yumanensis H. Allen, Monogr. Bats North Amer., Smithsonian 

 Misc. Coll., No. 165, p. 58, fig. 54-56, June, 1864.— Dobson, Catal. Chiroptera 

 Brit. Mus., pp. 328, 329, 1878.— H. Allen, Monogr. Bats North Amer., BuU. 

 U. S. Nat. Mus., No. 43, (1893), p. 72, March 14, 1894. 



Vespertilio obscurus H. Allen, Proc. Acad. Nat. Sci. Philadelphia, 1866, p. 281 

 (Lower California). — Milleb, North Amer. Fauna, No. 13, p. 69, October 16, 



