256 



MOVEMENT 



may be gathered 

 that the right 

 wing (Fig. 180, 3rd 

 image) was inclined 

 at an angle of about 

 50° with the verti- 

 cal, say 40° with 

 the horizontal. 



This inclination 

 necessarily varies at 

 different points of 

 the trajectory, and 

 must augment with 

 the rapidity of 

 movement ; the ob- 

 liquity reaching its 

 maximum in those 

 portions of the wing 

 which move with 

 the greatest velo- 

 city, namely, to- 

 wards the extremi- 

 ties. The result is 

 that the wing be- 

 comes twisted at 

 certain periods of 

 the movement. 



The tortion which 

 was reproduced in 

 the case of the wings 

 of our artificial in- 

 sects, may be ob- 

 served in some of the 

 photographs, as, for 

 instance, in the 4th 

 image in Fig. 181. 



