J>HENOMENA <0F PLIGHT IN THE ANIMAL KINGDOM. 



245 



iu all insects. These find tliat force as well in the period of elevation of 

 the wing as in the period of its depression, tnrning almost horizontally 

 the plane in which their wings move. The nnmerons varieties which 

 the mechanism of flight presents among the species of insects which we 

 have observed will be stiidied later; they do not conflict with the funda- 

 mental principles which I have just announced. 



The mechanical conditions which we have just passed in review I have 

 realized iu a theoretical apparatus, from which I have obtained the same 

 results as afforded by living insects. This artificial insect is represented 

 by Fig. 8. 



tc 



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