The colonel of Contra Guerrillas frowned a grim approval for his scout's handiwork of battered skulls. He was a man of frosted visage, a grisly Woden. The hard features were more stern for being ruggedly venerable. His beard was wiry, hoary gray, through whose billowy depth a long black cigar struck from clenched teeth. If eyes are windows of the soul, his were narrow, menacing slits, loopholes spiked by bristling brows. Two deep creases between the eyes furrowed their way up and were lost under an enormously wide sombrero. This sombrero was low crowned, like those worn farther to the south, and ornately flowered in silver. His chest was crossed with braid, cords of gold hung from the right shoulder to the collar, and the sleeves were as glorious as a bugler's. His brick-red jacket fell open from the neck, exposing the whitest of linen. His boots were yellow, his spurs big Mexican discs. Altogether the blend in him of the precise military and the easy ranchero was curiously picturesque. But Colonel Dupin, the Tiger of the Tropics, was a curious and picturesque man. His medals were more than he could wear, and each was for splendid daring. But on a time they had been stripped from him. It happened in China. He had made a gallant assault on the Imperial Palace, but he had also satiated his barbarian soul in carnage and loaded his shoulders with buccaneering loot. And though he wondered at his own moderation, a court martial followed. However, Louis Napoleon gave him back his medals, and sent him to Mexico to stamp out savagery by counter savagery. "There were two accomplices in this business," the Tiger was saying, "one a trader, Murguia----" "Killed him my very first shot," lied Tiburcio. He would save his golden goose of the golden eggs. "And the other, an American?" "Got away with the others, senor." Again Tiburcio's reason was obvious. The American, if taken, might tell things. "And"--Dupin gripped his cigar hungrily--"and Rodrigo?" For answer the scout waved a hand vaguely up the trail. "None went that way?" and the Colonel jerked his head toward the ravine. "No, none. Your Mercy saw me driving them back." "Quick, then, on your horse! We're losing time." Don Tiburcio was reluctant. He had not yet recovered his money from the American. "But the women, mi coronel? They are there, in that shack. Hadn't I better stay----?" "Jacqueline, you mean? Of course the little minx is in trouble, the second she touches land. But you come with me. She shall have another protector." Tiburcio knew the Cossack chief. He obeyed, and both men galloped away after the chase. [Illustration: "COLONEL DUPIN" "The Tiger of the Tropics ... the chief of Contra Guerrillas"]