The tumult which followed is beyond description. Billie's shout was as nothing compared to the cry of the ape as one of the bullets struck him in the leg and another pierced his foot. Loosing his hold upon the lad, he grabbed for the weapon, but Billie managed to evade him and would undoubtedly have slain the animal had not Strong sprung to his assistance, with the result that in another minute Billie was disarmed. Ill would the lad have fared then, at the hands of his two assailants, had not the noise attracted to the scene several soldiers, while an instant later came a loud shout as Donald and Adrian dashed into the patio. On the other side of the square they had heard Billie's shout, followed by the automatic, and had rushed to his aid. In another minute both Strong and his hairy friend were overcome and securely bound. "Where did you find him?" asked Donald, pointing to Strong. "Down there," was Billie's reply, as he pointed toward the still open underground passage way. "How did he get there?" "I suppose he entered from a similar entrance in Don Esteban's patio. I have had an idea all the time that there was some reason for the position of these two houses." "But it doesn't lead into the bank. How could he steal the box out of the vault?" "There is the real thief!" exclaimed Billie, pointing to the ape. "He sneaked in while Strong kept the bank employes engaged. By some mistake in his understanding he put the envelope back in the bank the next day instead of putting back the box. It was he who crawled through the bars into Santiago's library. He was also the devil who scared the maid almost into fits." "Well! Well!" exclaimed a voice from the gateway. "I never could have believed it." The voice was that of Don Esteban, who had entered while Billie was speaking. "I have come to see this strange man, Santiago Ojeda," he explained. "What says the doctor?" "Here comes the doctor now," announced Adrian as the physician made his appearance in the gateway. "He can speak for himself." CHAPTER XXXI. THE TREASURE OF MONTEZUMA. The shadows of evening had fallen and a cool breeze was blowing in off the Gulf of Mexico when a group of persons, among whom were the Broncho Rider Boys, gathered around the bedside of the sick man. It was as the physician had predicted, and when Santiago had awakened after his long sleep, he had regained his senses, although he was very weak. But as the day declined and the heat lessened he had become stronger, and now at his own request, Lucia and her friends drew around to listen to his tale. At one side of the bed stood Lucia, the three boys and Don Esteban. At the other stood Mr. Black, Josie and the physician, while at the foot of the bed was Strong, with Ambrosio in his arms, and a couple of soldiers who had the mountebank in custody.