Hendrickson 1950 Journal Sept. 1 Black Rock spring, 4500 ft., San Bernardino Co., Calif. spring again. Returned to camp and prepared specimens. After an early supper, the entire party except for Norris went to the spring in the truck. Saw a bucka at the spring - one shot at it apparently missed. Bailey and Russell went on in the truck to Joshua Tree for supplies. Miller, Jerry Russell, and I remained near the spring. Miller hunted Poor-Willis and Owls while Jerry Russell and I set up the nylon hair net for bats. Toole & Pipistrelles with the aid of the net. The bats were clearly able to detect the presence of even this very fine net, although the occasional ones which hit it indicated that this obstruction might be near their limits of perception. The net was stretched tightly in vertical position from the rocks above the spring out into the road. Its area was about 4' x 8'. I knelt at one side of it, attempting to place a hand over bats contacting the net. Many wheeled close about my head, and twice contacted the net in the act of circling my head. Many times bats approached very close to the net,