128 



ANIMAL LOCOMOTION. 



wing transversely, i.e, in the direction of the short axis of 

 the pinion. Flight perfect. 



Ux;p, 6. Removed one-half from either wing transversely, as 

 in experiment 5. Flight very slightly (if at all) impaired. 



Exj). 7. Divided either pinion in the direction of its long 

 axis into three equal parts, the anterior nervures being con- 

 tained in the anterior portion. Flight perfect. 



Exp. 8. Notched two-thirds of either pinion obliquely from 

 behind. Flight perfect. 



Exp. 9. Notched anterior third of either pinion transversely. 

 The power of flight destroyed. Here, as in experiment 4, 

 the mutilation of the anterior margin was followed by loss of 

 function. 



Exp. 10. Detached posterior two-thirds of right wing in 

 its long axis, the left wing being untouched. Flight perfect. 

 I expected that this experiment would result in loss of 

 balancing-power ; but this was not the case. 



Exp. 11. Detached half of right wing transversely, the left 

 one being normal. The insect flew irregularly, and came to 

 the ground about a yard from where I stood. I seized it 

 and detached the corresponding half of the left wing, after 

 which it flew away, as in experiment G. 



Dragon-Fly. — Exp. 12. In the dragon-fly either the first or 

 second pair of wings may be removed without destroying the 

 power of flight. The insect generally flies most steadily 

 when the posterior psdr of wings are detached, as it can bal- 

 ance better; but in either case flight is perfect, and in no 

 degree laboured. 



Exj). 1 3. Removed one-third from the posterior margin of 

 the first and second pairs of wings. Flight in no wise impaired. 



If more than a third of each wing is cut away from the 

 posterior or thin maigin, the insect can still fly, but with 

 effort. 



Experiment 13 shows that the posterior or thin flexible 

 margins of the wings may be dispensed with in flight. They 

 are more especially engaged in propelling. Compare with 

 experiments 1 and 2. 



Exp. 14. The extremities or tips of the first and second 

 pair of wings may be detached to the extent of one-third, 



