“Yes,” answered Jacinto.  “I came in to see what was the matter with you.  Are you ill?”

“No, of course not,” said Ned, a bit shortly.  “I—­I had a bad dream, that was all.  All right now.”

“For that I am glad.  Try to get all the sleep you can, for we must start early to avoid the heat of the day,” and there was the sound of the guide leaving and arranging the folds of the mosquito net behind him to keep out the night-flying insects.

Once more Ned composed himself to sleep, and this time successfully, for he did not have any more unpleasant dreams.  The quiet of the jungle settled down over the camp, at least the comparative quiet of the jungle, for there were always noises of some sort going on, from the fall of some rotten tree limb to the scream or growl of a wild beast, while, now and again, from the river came the pig-like grunts of the alligators.

It was about two o’clock in the morning, as they ascertained later, when the whole camp—­ white travelers and all—­was suddenly awakened by a wild scream.  It seemed to come from one of the natives, who called out a certain word ever and over again.  To Tom and Ned it sounded like: 

“Oshtoo!  Oshtoo!  Oshtoo!”

“What’s the matter?” cried Professor Bumper.

“The vampires!” came the answering voice of Jacinto.  “One of the Indians has been attacked by a big vampire bat!  Look out, every one!  It may be a raid by the dangerous creatures!  Be careful!”

Notwithstanding this warning Ned stuck his head out of the tent.  The same instant he was aware of a dark enfolding shadow passing over him, and, with a shudder of fear, he jumped back.

CHAPTER XII

A FALSE FRIEND

“What is it?  What’s the matter?” cried Tom springing from his cot and hastening to the side of his chum in the tent.  “What has happened, Ned?”

“I don’t know, but Jacinto is yelling something about vampires!”

“Vampires?”

“Yes.  Big bats.  And he’s warning us to be careful.  I stuck my head out just now and I felt that same sort of shadow I felt this evening when we were down near the river.”

“Nonsense!”

“I tell you I did!”

At that instant Tom flashed a pocket electric lamp he had taken from beneath his pillow and in the gleam of it he and Ned saw fluttering about the tent some dark, shadow-like form, at the sight of which Tom’s chum cried: 

“There it is!  That’s the shadow!  Look out!” and he held up his hands instinctively to shield his face.

“Shadow!” yelled Tom, unconsciously adding to the din that seemed to pervade every part of the camp.  “That isn’t a shadow.  It’s substance.  It’s a monster bat, and here goes for a strike at it!”

He caught up his camera tripod which was near his cot, and made a swing with it at the creature that had flown into the tent through an opening it had made for itself.