Rapidly the individual points of light grew, becoming tiny stars that glowed by the reflected light of the sun. Within five minutes there was no longer any chance of mistaking their identity, for their flat disc-like shapes and the half-human forms of the things that rode them were already visible through the binoculars. They were approaching at terrific velocity. Both Jan and Austin knew them to be subjects of Alkebar. There was no mistaking their motive. Doubtless orders had been flashed to them from the disabled _Selba_. Realizing that these fleet space riders could easily catch up with his flier if they so chose, Shelby made no attempt to elude them. Instead he clung doggedly to the straight course toward Mars. The twin machine guns, responding obediently to their directing mechanism, swung on their swivel toward the hurtling foes. Shelby peered into the eye-piece of the "sighter," a complicated arrangement of mirrors and lenses which enabled the pilot to always look directly through the ring-sights regardless of what direction the gun barrels were pointing. He pressed the trips, and soundlessly, out in the vacuum of space, the guns went into action. Flickering green flames of detonating radio-active explosive darted from their muzzles. Almost immediately there were answering flashes among the approaching shapes, for the high-calibre bullets were also loaded with explosive. One projectile took effect--another! Emerald flares of light, and nothing remained of two bold space men and their queer disc-like vehicles but torn fragments of flesh and metal. The Space Men were very close now. Jan and Shelby could see the light flashing on their jeweled harnesses and on the weapons which they flourished defiantly. There must have been almost five hundred in the party. Somehow their wild charge was vaguely reminiscent of a band of fierce Bedouin marauders, racing madly across the desert, bent on pillage. Only it was the Arabs who suffered by this comparison, for the desert of these mysterious Space Men was the whole of interstellar emptiness; and their forms and those of the things they rode, were the forms of the forces of Iblees himself. Apparently these henchmen of Alkebar had some object in view other than the mere destruction of the flier, for they made no move to use their weapons. They were pulling upon levers on their vehicles, checking their headlong flight. Now they were coursing with the little craft, swarming about it, edging nearer, at the same time taking care to keep out of range of Shelby's guns.