IIIDUNCAN DID NOT SEE the arrow coming. He heard the swishing whistle and felt the wind of it on the right side of his throat and then it thunked into a tree behind him. He leaped aside and dived for the cover of a tumbled mound of boulders and almost instinctively his thumb pushed the fire control of the rifle up to automatic. He crouched behind the jumbled rocks and peered ahead. There was not a thing to see. The hula-trees shimmered in the blaze of sun and the thorn-bush was gray and lifeless and the only things astir were three stilt-birds walking gravely a quarter of a mile away. “Sipar!” he whispered. “Here, mister.” “Keep low. It’s still out there.” Whatever it might be. Still out there and waiting for another shot. Duncan shivered, remembering the feel of the arrow flying pas