370 NORTH AMERICAN FAUNA [No. 55 



General habits. At Watson, July 21, 1915, Preble says that among 

 the large number of bats seen flying evenings there were always a 

 few that seemed referable to this species. On July 13 he shot one at 

 the head of the canyon about 5 miles north of Sheaville, where bats 

 were numerous. At Eiverside, Sheldon and the writer shot two of 

 these bats among many others that flew swiftly about the barns every 

 evening. In Kiger Gorge, in the Steens Mountains, August 24 and 

 25, Sheldon and Becker collected three specimens among the aspens 

 around their cabin. At Paulina Lake, Goldman shot one August 16, 

 1914, from among the small bats flying 1 over the lake and creek. 

 At Malheur Lake a dead and mummified specimen was picked up on 

 the porch at Springers Ranch, and on August 12, Watson and the 

 writer knocked down two with gunny sacks as they flew about in an 

 old shop at about 8 p. m. Both were adult females and fat, with 

 full stomachs. The larger weighed 8.8 g, and its stomach full of 

 finely masticated insects, weighed 2.4 g, or approximately one-quar- 

 ter of its total weight. This amount of food merely represented one 

 meal the bat's supper, and another full meal, and probably some 

 lunches in between, would certainly be eaten before it retired to roost 

 in the morning. The bat would thus consume at least half its weight 

 in insects each night, even when fat and heavy, or near its own 

 weight when lean and light. Both of these bats were fat enough 

 to hibernate at the first cold weather, but where they go to pass the 

 winter is not yet known. 



Breeding habits. In the Devils Kitchen, a large warm cave near 

 the Mammoth Hot Springs in Yellowstone Park, these bats gather 

 in a colony for breeding. On July 11, 1915, several hundred were 

 found in the cave, all of those collected being females, and each con- 

 taining one large foetus nearly ready for birth. They were gathered 

 in bunches of sometimes 50 or more in a place, in the crevices of the 

 cave wall, clinging to the rocks or to each other, and the writer could 

 easily put out his hand and take as many as he wished. They would 

 bite fingers as hard as they could, but without breaking the skin or 

 doing any harm. 



This was evidently only a breeding colony, as on September 18, 

 when the cave was again visited, the bats were all gone, evidently for 

 cooler winter quarters where hibernation would be possible. 



MYOTIS YUMANENSIS SOCIABILIS H. W. GEINNELL 

 TEJON BAT 



My otis yumanensis sociabilis H. W. Grinnell, Calif. Univ. Pubs., Zool. v. 12, 

 p. 318, 1914. 



Type. Collected at Old Fort Tejon, Calif., by Joseph Grinnell, July 23, 

 1904. 



General characters. Size small, color between that of the very pale Myotis 

 yumanensis of the Colorado Desert region and the dark M . yumanensis saturatus 

 of the Northwest coast region. Upper parts " tawny-olive " or sepia ; lower 

 parts dull whitish or buffy ; ears and membranes pale brownish in color, poste- 

 rior edges of membranes sometimes whitish. 



Measurements. Adult female from Eagle Lake, Calif. : Total length, 87 mm ; 

 tail, 37; foot, 10; ear (dry), 12; forearm, 37; spread of wings, 240 (Bunnell). 

 Average of five adult males (Grinnell) : 81 ; 33 ; 8; forearm, 34. Weight of adult 

 female 6.4 g (Grinnell, Dixon, and Linsdale, 1930, p. 455). 



Distribution and habitat. Southeastern British Columbia and 

 southward east of the Cascades and west of the Sierra Nevadas to 



