388 NORTH AMERICAN FAUNA [No. 55 



The food and breeding habits of this dark form are little known 

 but probably do not differ materially from those of the other sub- 

 species of the group. 



CORYNORHINUS RAFINESQUII PALLESCENS MIT.LF.R 

 PALE JACK-BABBIT BAT 



Corynorhinus macrotis pallescens Miller, North Amer. Fauna No. 13, p. 52, 

 1897. 



Type, Collected at Keam Canyon, Navajo County, Ariz., August 3, 1894, by 

 A. K. Fisher. 



General characters. Paler and brighter in color than townsendii or inter- 

 inedius. Other characters about the same. Typical specimens light fawn or sor- 

 rel brown, paler below, ears and membranes slightly darker brown than the 

 fur. 



Measurements. Adult male from Malheur Cave: Expanse of wings, 305 

 mm. Total length, 102; tail, 51; foot, 11; ear, 36. Weight 10.7 g (not fat). 



Distribution and habitat. This pale form of the long-eared bats 

 probably occupies the whole Upper Sonoran valley country of east- 

 ern Oregon, although but few localities are represented by specimens 

 (fig. 101). It has a wide range over both Upper and Lower Sonoran 

 Zones of the arid region from Oregon to Mexico. There are speci- 

 mens from Malheur Cave, about 20 miles east of Malheur Lake, and 

 from a cave about 15 miles southwest of Carol, on the western edge 

 of Malheur County, and Cantwell reported them near Paradise in the 

 Grand Ronde Canyon, but did not collect any specimens. 



General habits. These are cave-dwelling bats and in eastern Ore- 

 gon they inhabit the lava caves probably more generally than at 

 present known. On August 13, 1920, the Malheur Cave, about 20 

 miles east of Malheur Lake, was visited and a few of these bats were 

 found hanging from the broadly arched lava roof of the main tun- 

 nel. The air of the cave was cool, but the bats were active and easily 

 alarmed. Only one specimen was secured, an adult male in thin 

 summer condition. 



On February 17, 1916, E. F. Mickey, of Jordan Valley, visited a 

 lava cave farther south in western Malheur County where, in April 

 of the previous year, he had seen several hundred bats clinging to 

 the roof. He found them there again and collected and sent to the 

 Biological Survey a series of specimens of the pale jack-rabbit bats. 

 He picked them from the roof of the cave where they were hanging 

 8 to 12 feet from the floor, mainlv 1 in a place, but a bunch of 3 

 were found clinging 1 together. This cave has a small entrance and 

 the temperature is evidently sufficiently uniform for a winter resort 

 of bats. It is a well-known fact that they cannot winter either in 

 caves where the temperature reaches the freezing point or in those 

 where the air is too warm. 



Breeding habits. With these bats the mating season seems not 

 to be definitely known, but it must be in late summer, as small em- 

 bryos are found in females just entering hibernation in September 

 and October. For the approximate date of birth of the young there 

 are numerous records, but none so definite as that obtained by E. R. 

 Hall from a breeding cave at the north end of Pyramid Lake, Nev., 

 only a little south of the Oregon line. Of 19 adult females found 

 hanging from the roof of the cave on June 28, 1924, 14 carried each 

 1 small young clinging to her body, 1 young was found still attached 



