He had not gone more than a dozen steps, before he heard the soft pat-pat behind him, and on looking back could see nothing but the waving grass to indicate the whereabouts of his erstwhile assailant. "So I am to be followed, am I? Well, all right." Then, as an afterthought: "I wonder how I can catch him when I want him. I wonder if this will do," and he raised his weapon and pointed it toward the moving grass. With the same plaintive cry which Billie had come to recognize as one of fear, the animal ran toward him and sank to his knees. Billie smiled. "It's all right, old chap. As long as I know how to handle you, why you can follow me right back to the train." Again he started down the track at a brisk walk, it having just occurred to him that there might be something doing at the other end of his journey. Twenty minutes later he reached the station at Pitahaya where he had expected to find Adrian and the three Mexicans awaiting him, but, as we know, they had gone on to the scene of the wreck. Not realizing just what had happened, but always on the alert for the unexpected, Billie, therefore, began an inspection of the station. It did not take him long to discover that Pitahaya was little more than a siding with a one-room building, which was used as a freight house and a waiting room. It did not even boast of a station master. "There must be some reason for having a building here," he mused. "There must be some sort of a settlement around somewhere. But what's that to me? I might as well be jogging along towards Pachuca." Then he bethought him of the ape, which he had no mind to lose after his exciting experience. But the animal was nowhere to be seen. "I wonder if I could raise him with a shot," soliloquized Billie. He raised his weapon, which he still carried in his hand, and fired aimlessly, while he turned his eyes in various directions, but there was nothing to be seen. "Oh, well," he thought, "what's the difference? He'd just be a nuisance anyway. I might as well be trudging along." He jumped off the station platform and proceeded down the track, filling the magazine to his automatic as he went. Then having finished the task, he returned it to his holster and once more began counting the ties. "One, two, three, four, five, six----" Bing! And a stone whistled by his head. Billie turned, and as he did so a second stone from the same source struck him on the temple, and he fell to the ground. A second later the ape sprang from a palm beside the station and ran toward him, stopping every few feet to see if the lad would rise. When within a few feet of the prostrate lad the animal made a leap and landed upon his body. In another instant it had gained possession of Billie's weapon, which it examined curiously for a moment, ere it sprang away and stationed itself some two rods distant, where it sat watching with the weapon aimed directly at him.