“What alarmed you?” asked Randolph Rover hurriedly.

“I heard a rustling in the bushes up there perhaps, though, it was only a bird or some small animal.”

“I can see nothing, Dick.”

“Neither can I; but I am certain —­ Out of sight, Uncle Randolph, quick!”

Dick caught his uncle by the arm, and both threw themselves flat behind the rocks.  Scarcely had they gone down than two spears came whizzing forward, one hitting the rocks and the other sailing over their heads and burying itself in a tree trunk several yards away.  They caught a glance of two natives on the rocks over them, but with the launching of the spears the Africans disappeared.

CHAPTER XXVIII

KING SUSKO

“My gracious, this is getting at close range!” burst out Dick, when he could catch his breath again.  “Uncle Randolph, they meant to kill us!”

“Indeed they did, Dick.  And this is no safe place for stopping.  We must retreat.”

“But Cujo —?”

“He must be cautioned.”  Randolph Rover raised his voice.  “Cujo!  Cujo!  They have discovered us!  Take care that they do not spear you.”

No reply came back to this call, which was several times repeated.  Then came a crash, as a big stone was hurled down, to split into a score of pieces on the rock which sheltered them.

“They mean to dislodge us,” said Dick.  “If they would only show themselves -”

He stopped, for he had seen one of the Bumwos peering over a mass of short brush directly over the cave entrance.  Taking hasty aim with his pistol be fired.

A yell of pain followed, proving that the African had been hit.  But the Bumwo was not seriously wounded, and soon he sent another stone at them, this time hitting Randolph Rover on the leg.

“Oh!” gasped Dick’s uncle, and drew up that member with a wry face.

“Did he hurt you much, Uncle Randolph?”

“He hurt me enough.  You villain, take that!” And now the man fired, but the bullet flew wide of its mark, for Randolph Rover had practiced but little with firearms.

They now thought it time to retreat, and, watching their chance, they ran from the rocks to the trees beyond.  While they were exposed another spear was sent after them, cutting its way through Mr. Rover’s hat brim and causing that gentleman to turn as pale as a sheet.

“A few inches closer and it would have been my head!” he ejaculated.  “This is growing too warm for comfort.  Perhaps we had better rejoin the others, Dick.”

“Cujo!  Cujo!  Where are you?” cried the boy once more.  But as before no answer came back.

The shots had alarmed the others of the expedition, and all were hurrying along the rocky ledge when Randolph Rover and Dick met them.

“We must turn back!” exclaimed Randolph Rover.  “If you go ahead we may be caught in an ambush.  The Bumwos have discovered our presence and mean to kill us if they can!”