From this it follows that if the horse possessed the same strength as this last insect, or if the insect were the size of a horse, they would either of them be able to draw 155,250 lbs. M. Plateau has ascertained the pushing power in insects, by introducing them into a pasteboard tube, the interior of which was made rough, and in which was fixed a glass plate, which allowed the light to penetrate into the prison. The animal, if excited, struggled with all its strength against the transparent plate, which, on being pushed forward, turned a lever adapted to a miniature dynamometer, which indicated the amount of effort exercised. The results thus obtained prove that the pushing power, like the power of traction, is greater in inverse proportion to the size and weight of the animal. A few figures will better explain this curious law. In _Oryctes nasicornis_ the proportion of the pushing power to the weight of the insect is only three to two; in _Geotrupes stercorarius_ it is sixteen to two; and in _Onthophagus nuchicornis_ seventy-nine to six. Experiments have been made on the lifting power of insects by fastening a ball of soft wax to a thread attached to the hind legs. The proportion of the weight lifted has been found equal to that of the body. That is to say, that the insect, when flying, can lift its own weight. This is proved by the following calculations:--In the Neuroptera the proportion is 1 in the Dragon-fly (_Libellula vulgata_), ·7 in _Lestes sponsa_. In the order Hymenoptera it is ·78 in the bee, and ·63 in _Bombus terrestris_, the humble-bee. In the Diptera it is ·9 in _Calliphora vomitoria_,[8] 1·84 in the _Syrphus corollæ_, and 1·77 in the house-fly. [8] The meat-fly.--ED. These results show that insects have only sufficient power to sustain their own weight when flying, as the above calculations exhibit the maximum of which they are capable, and at the utmost this strength would only compensate for the fatigue occasioned by the action of flight.