Now, what are the balls composed of? There comes the oddest part of the whole odd proceeding. The plain truth of it is that the sacred beetles are assistant scavengers--imperfect Southern and Oriental substitutes for a main drainage system. The balls consist of dung, dirt, and refuse, and the beetles collect them on the open, dry them hard in the sun, roll them to the mouths of their burrows, and then live on them till the ball has all been eaten. It is the funniest thing in the world to watch them. They tumble about in the loose sand and stumble over little eminences in the most comical fashion. No. 5 shows a pair of scarabs engaged in this habitual and quaint amusement. They have each collected a round mass of manure, and rolled and dried it nicely into shape; they are now engaged in trundling their booty off at their leisure to a place of safety. But they are obliged to push the balls backward with their long hind legs: and as this precludes the possibility of the scarab seeing where it is going, each beetle pauses every now and again and turns round, like a man sculling in a boat alone, to look what is ahead of him. Sometimes in doing so he loses his ball, a misfortune which has just happened to the beetle on the right in No. 5. The precious pellet goes bounding off down hill as fast as gravitation will take it. In this case, the disappointed little workman faces round and darts after it at full speed, going forward now instead of backward, and trying to head the ball as it rolls down the uncertain slope of the sand-hills. If he succeeds, he puts himself in front of the ball as it falls, catches it with his hind legs, and begins once more laboriously to push it backward up hill again, towards the mouth of his hole. But as the pellets roll quickly, and the beetles are by no means rapid runners, he seldom succeeds in recovering his own property, unless the ball happens to catch for a moment on some projecting little hillock of sand, or be checked on its downward course by a weed, a stick, or a dead shell or starfish. [Illustration: 5.--SACRED SCARABS ROLLING THEIR FOOD-BALLS BACKWARD (THE INSECT TO THE RIGHT HAS LOST HIS DINNER).]