Birds, quadrupeds, and reptiles were resting motionless after the fatigues of the day, and the silence of the desert brooded over the far-spreading Pampas.

Glenarvan, Robert, and Thalcave, had followed the common example, and lay in profound slumber on their soft couch of lucerne. The worn-out horses had stretched themselves full length on the ground, except Thaouka, who slept standing, true to his high blood, proud in repose as in action, and ready to start at his master's call. Absolute silence reigned within the inclosure, over which the dying embers of the fire shed a fitful light.

However, the Indian's sleep did not last long; for about ten o'clock he woke, sat up, and turned his ear toward the plain, listening intently, with half-closed eyes. An uneasy look began to depict itself on his usually impassive face. Had he caught scent of some party of Indian marauders, or of jaguars, water tigers, and other terrible animals that haunt the neighborhood of rivers? Apparently it was the latter, for he threw a rapid glance on the combustible materials heaped up in the inclosure, and the expression of anxiety on his countenance seemed to deepen. This was not surprising, as the whole pile of ALFAFARES would soon burn out and could only ward off the attacks of wild beasts for a brief interval.

There was nothing to be done in the circumstances but wait; and wait he did, in a half-recumbent posture, his head leaning on his hands, and his elbows on his knees, like a man roused suddenly from his night's sleep.

A whole hour passed, and anyone except Thalcave would have lain down again on his couch, reassured by the silence round him. But where a stranger would have suspected nothing, the sharpened senses of the Indian detected the approach of danger.

As he was thus watching and listening, Thaouka gave a low neigh, and stretched his nostrils toward the entrance of the RAMADA.

This startled the Patagonian, and made him rise to his feet at once.

"Thaouka scents an enemy," he said to himself, going toward the opening, to make careful survey of the plains.

Silence still prevailed, but not tranquillity; for Thalcave caught a glimpse of shadows moving noiselessly over the tufts of CURRA-MAMMEL. Here and there luminous spots appeared, dying out and rekindling constantly, in all directions, like fantastic lights dancing over the surface of an immense lagoon. An inexperienced eye might have mistaken them for fireflies, which shine at night in many parts of the Pampas; but Thalcave was not deceived; he knew the enemies he had to deal with, and lost no time in loading his carbine and taking up his post in front of the fence.

He did not wait long, for a strange cry--a confused sound of barking and howling--broke over the Pampas, followed next instant by the report of the carbine, which made the uproar a hundred times worse.

Glenarvan and Robert woke in alarm, and started to their feet instantly.

"What is it?" exclaimed Robert.

"Is it the Indians?" asked Glenarvan.

"No," replied Thalcave, "the AGUARAS."

"AGUARAS?" said Robert, looking inquiringly at Glenarvan.

"Yes," replied Glenarvan, "the red wolves of the Pampas."

They seized their weapons at once, and stationed themselves beside the Patagonian, who pointed toward the plain from whence the yelling resounded.

Robert drew back involuntarily.

"You are not afraid of wolves, my boy?" said Glenarvan.

"No, my Lord," said the lad in a firm tone, "and moreover, beside you I am afraid of nothing."

"So much the better. These AGUARAS are not very formidable either; and if it were not for their number I should not give them a thought."

"Never mind; we are all well armed; let them come."

"We'll certainly give them a warm reception," rejoined Glenarvan.

His Lordship only spoke thus to reassure the child, for a secret terror filled him at the sight of this legion of bloodthirsty animals let loose on them at midnight.

There might possibly be some hundreds, and what could three men do, even armed to the teeth, against such a multitude?

As soon as Thalcave said the word AGUARA, Glenarvan knew that he meant the red wolf, for this is the name given to it by the Pampas Indians.