There was a breathless moment during which the four men followed the erratic course of the spark. Then Antonio chuckled. "Alabaos! A light-bug," said he. "Don't you know a cucullo when you see one?" He cautiously tested the ejector of his carbine and tightened the cord that served as his belt. O'Reilly drew a deep breath of relief. He had never become wholly accustomed to the giant light-beetles of the tropics, although he had carried one often on sentry duty to see the face of his watch, and not infrequently had seen Cuban women wearing them in their hair as ornaments. "Jove!" he muttered. "It gave me a fright." Hilario resumed his instructions: "If anything goes wrong, wait here. Don't ride away until we have time--" "Never fear. I won't desert you," the American reassured him. The two white-clad figures slipped away, became indistinct, and then disappeared. The night was hot, the mosquitoes hummed dismally and settled in clouds upon the waiting pair, maddening them with their poison. After a time a horse snorted and Jacket cursed nervously. "I'd like to see where we are," the boy muttered. "Do you know these men?" O'Reilly asked him. "No. God deliver me from such unpleasant fellows." "I hope they're honest." "Humph! I trust nobody." There was a pause. "Never mind," Jacket assured his companion. "I will make short work of them if they prove to be traitors." A half-hour passed, then the two ghostly figures materialized once more. "Dios!" grumbled Hilario. "There are many strings to this Spanish guitar. What a row when they discover that I have played a Cuban danzon upon it." The old man seemed less surly than before, and O'Reilly felt ashamed of his recent suspicions. "Is the way clear?" he inquired. "As far as the railroad, yes. We heard voices there, and came back. We will have to cut our way forward after we cross the track. Now then, follow me without a sound."