The Beetle walks two or three times round his pellet. Discovering nothing to account for its immobility, he returns to the rear and starts pushing again. The ball remains stationary. ‘Let’s look up above.’ The Beetle goes up, to find nothing but his motionless colleague, for I had taken care to drive in the pin so deep that the head disappeared in the ball. He explores the whole upper surface and comes down again. Fresh thrusts are vigorously applied in front and at the sides, with the same absence of success. There is not a doubt about it: never before was Dung-beetle confronted with such a problem in inertia. Now is the time, the very time, to claim assistance, which is all the easier as his mate is there, close at hand, squatting on the summit of the ball. Will the Scarab rouse him? Will he talk to him like this: ‘What are you doing there, lazybones? Come and look at the thing: it’s broken down!’ Nothing proves that he does anything of the kind, for I see him steadily shaking the unshakable, inspecting his stationary machine on every side, while all this time his companion sits resting. At long last, however, the latter becomes aware that something unusual is happening; he is apprised of it by his mate’s restless tramping and by the immobility of the ball. He comes down, therefore, and in his turn examines the machine. Double harness does no better than single harness. This is beginning to look serious. The little fans of the Beetles’ antennæ open and shut, open again, betraying by their agitation acute anxiety. Then a stroke of genius ends the perplexity: ‘Who knows what’s underneath?’ They now start exploring below the ball; and a little digging soon reveals the presence of the pin. They recognize at once that the trouble is there. If I had had a voice in their deliberations, I should have said: ‘We must make a hole in the ball and pull out that skewer which is holding it down.’