to keep up with a beetle.  It was the most tedious thing I have ever gone through.  And as we dawdled along behind, watching him like hawks lest we lose him under a leaf or something, we all got so cross and ill-tempered we were ready to bite one another’s heads off.  And when he stopped to look at the scenery or polish his nose some more, I could hear Polynesia behind me letting out the most dreadful seafaring swear-words you ever heard.

After he had led us the whole way round the mountain he brought us to the exact spot where we started from and there he came to a dead stop.

“Well,” said Bumpo to Polynesia, “what do you think of the beetle’s sense now?  You see he doesn’t know enough to go home.”

“Oh, be still, you Hottentot!” snapped Polynesia.  “Wouldn’t you want to stretch your legs for exercise if you’d been shut up in a box all day.  Probably his home is near here, and that’s why he’s come back.”

“But why,” I asked, “did he go the whole way round the mountain first?”

Then the three of us got into a violent argument.  But in the middle of it all the Doctor suddenly called out,

“Look, look!”

We turned and found that he was pointing to the Jabizri, who was now walking up the mountain at a much faster and more business-like gait.

“Well,” said Bumpo sitting down wearily; “if he is going to walk over the mountain and back, for more exercise, I’ll wait for him here.  Chee-Chee and Polynesia can follow him.”

Indeed it would have taken a monkey or a bird to climb the place which the beetle was now walking up.  It was a smooth, flat part of the mountain’s side, steep as a wall.

But presently, when the Jabizri was no more than ten feet above our heads, we all cried out together.  For, even while we watched him, he had disappeared into the face of the rock like a raindrop soaking into sand.

“He’s gone,” cried Polynesia.  “There must be a hole up there.”  And in a twinkling she had fluttered up the rock and was clinging to the face of it with her claws.

“Yes,” she shouted down, “we’ve run him to earth at last.  His hole is right here, behind a patch of lichen—­big enough to get two fingers in.”

“Ah,” cried the Doctor, “this great slab of rock then must have slid down from the summit and shut off the mouth of the cave like a door.  Poor fellows!  What a dreadful time they must have spent in there!—­ Oh, if we only had some picks and shovels now!”

“Picks and shovels wouldn’t do much good,” said Polynesia.  “Look at the size of the slab:  a hundred feet high and as many broad.  You would need an army for a week to make any impression on it.”

“I wonder how thick it is,” said the Doctor; and he picked up a big stone and banged it with all his might against the face of the rock.  It made a hollow booming sound, like a giant drum.  We all stood still listening while the echo of it died slowly away.