The Mexicans saw the force of Vasco’s arguments. They did not care about being shot at like wild beasts, and they knew that the boys and the professor were ready for anything now.

“We will try to-morrow night,” said Bilette, as, with Noddy and his men, he silently withdrew to where the horses and auto had been left. “Perhaps we’ll have better luck then.”

The men growled, but had to accept the situation. As for our friends, they were too excited to sleep any more that night, and so they sat around the camp-fire and talked until morning.

Breakfast over, camp was broken, and once more the auto started on the trip toward the hidden city. Professor Snodgrass got out the map made by his dead friend and studied it carefully.

“I believe we are on the right road,” the naturalist said. “Here is a highway marked on the drawing that seems to correspond with the one we are on. And there is a place marked where two roads diverge. Only there is nothing said about the laughing serpent, though there is something here that might be taken for it,” and he pointed to the map.

Every one was becoming quite anxious, and the boys, as well as the professor, kept close watch on each foot of the way to see if there were any indications that they were close to the underground town.

They stopped for dinner near a little brook, in which Bob caught several fish that made a welcome addition to the bill of fare.

“Now, if you boys don’t object, I think I’ll take a little stroll into the woods and see what I can find in the way of specimens,” remarked the naturalist, as he finished the last of his fish and frijoles.

“Better take a gun along,” called Ned. “A jaguar may get you.”