Thuleer 1958 Species Account. July July 18 (end) Macrotus californicus p.2. Later we went further west to a mine (Locality: Mine, 1040+ ft, 5.8 mi.S., 0.3 mi.E. Vidal, Riverside Co., Calif.) We proceeded up the canyon until it swung to the left (south?) and then up and over a saddle and down into a relative wide (Perhaps 1/2 mile) valley. This is on the upper part of the canyon we had just left. The mine is on the south side of the valley about 50 yards above the stream bed. These were loaded with bats of this species. There were only a few, interconnecting horizontal shafts with some bats in them. The majority were in great clusters in an area where a wide vein of ore had been removed. The upper end of this sloping shaft was almost blocked by fallen rubble and a caving in of the roof. This shaft ended in a deep vertical shaft that offered no means of entrance. Many bats were seen flying in this shaft. I got [illegible] about 40 bats from here of which 21 were later put up. (623-643) Beck collected about [illegible] 75 more. There were at least 1500 bats of this species here. In several places their favorite roosts were marked by great piles of guano. July 19. Upon returning to the Mountaineer (New Era) Mine we found none of this species. At the second mine, the one further west we saw only about 150 of this species and Beck secured another 40.