1917.] 



Lang and Chapin, Field Notes on African Chiroptera. 



503 



together that 6 were brought down by a single discharge of the gun, only 

 one of them an adult male. On the other hand, near Avakubi, a lone bat 

 was disturbed during the day in the undergrowth, and flapped out close 

 beside us. 



Throughout February and March, 1914, a number of these huge noisy 

 bats used to gather in the trees along the forested bank of the Ituri River 

 a couple of miles above Avakubi, where we camped and observed their 

 habits closely. Every evening, shortly after sunset — about 6.15, to be 

 exact — some 30 of them would be seen crossing the stream to the south 

 bank, not in a flock but singly, in straggling fashion. Entering the trees 



Fig. 18. Hypsignalhus monstrosus. Head of adult male (No. 48657). The heavy broken line 

 indicates extent of cheek-pouch, §■. 



on the far shore, they would start at once to call. Each individual gave a 

 loud pwok! or Icwok!, repeated at short intervals, say of J to J of a second, 

 though occasionally several notes would be emitted in very rapid succession. 



This noise would continue without serious interruption till 10 or 11 

 o'clock, to be taken up again at intervals later on, but ceasing entirely by 

 half an hour before daylight. We never saw them recross the river. 



During this performance their utter lack of fear was amazing. Neither 

 talking, rapping on the trees, lighting a lantern, nor even firing a gun could 

 induce them to cease their calling. Their chorus made us think of a pond- 

 ful of noisy American wood-frogs, greatly magnified and transported to the 

 tree-tops. 



