1914] Grinnell: Mammals and Birds of the Colorado Valley 263 



Corynorhinus macrotis pallescens Miller 

 Pale Lump-nosed Bat 

 At Riverside Mountain, California, March 18, three bats were found 

 at the end of a sloping drift in the Steece copper mine. They were 

 clinging to the rock wall, and at once took flight, attempting to pass 

 us towards the opening of the tunnel. Two were secured, nos. 10694, 

 10695. The fur of these has a slight reddish cast, which is doubtless 

 wholly adventitious, due to the fine, sticky red dust with which the walls 

 of the mine were covered. Both were females, one of them containing 

 a single embryo. 



Antrozous pallidus pallidus (LeConte) 

 Desert Pallid Bat 

 On several nights in April, large light-colored bats were moment- 

 arily observed flitting about in the moonlight close over our beds. 

 At times the flutter of their wings was clearly audible. But they 

 seldom appeared until it was too dark to shoot. On April 20, on the 

 California side, eight miles east of Picacho, a specimen was shot at 

 late dusk as it flew among willows across a patch of open sky. This, 

 the only example of the species obtained (no. 10696), was a female 

 containing two embryos. 



Myotis occultus Hollister 

 Hollister Bat 

 This very distinct species was only recently described (Hollister, 

 1909, p. 43) from two specimens taken May 14 and 15, 1905, on the 

 California side of the river in the bottomlands ten miles above Needles. 

 The fact that our own expedition failed to detect the presence of this 

 bat until the first week in May would point towards its late spring 

 arrival in the region generally. We obtained six specimens, as listed 

 in the accompanying table of measurements. The first was shot at 

 late dusk close to the river bank between files of cottonwoods, in just 

 the same association as those taken by Hollister. At our second locality 

 of capture, the remaining five specimens were shot over the water in 

 a back eddy of the river. Here these bats arrived in considerable num- 

 bers at early dusk to drink, flitting down to the water's surface and 

 dipping several times before flying off among the willows and cotton- 

 woods. We used a boat in shooting and retrieving the specimens 

 obtained. 



