XVIII 



DRAGON-FLIES 



417 



In the Odonata the two wings of each pair are quite free, but 

 they are perhaps brought into correlative action by means of a 

 lever of unusual length existing amongst the chitinous pieces in 

 the body wall at the base of the wings (Fig. 263, l). The wing 

 muscles are large ; according to von Lendenfeld ^ there are three 

 elevator, five depressor, and one adductor muscles to each wing : 

 he describes the wing movements as the results of the correlative 

 action of numerous muscles and ligaments, and of a great num- 

 ber of chitinous pieces connected in a jointed manner. 



Amans^ has suggested that the mechanism of flight of the 

 dragon-fly would form a suitable model for a flying-machine, to 

 be propelled by electricity. 



Fig. 264. Platycnemis pennipes, <?, Britain. 



The Zygopterides the second of the. two divisions of the 

 Odonata are Insects different in many respects from the large 

 and robust Anisopterides. The division comprises the delicate 

 Insects called " demoiselles," damsel-flies, by the French (Fig. 

 262, A, and Fig. 264). Great power of flight is not possessed by 

 these more fragile Insects ; they flit about in the most gentle 

 and airy manner from stem to stem of the aquatic plants and 

 grasses that flourish in the localities they love. To this group 

 belong the fairy-like Insects of the genus Calepteryx, in which 

 various parts of the body and wings are suffused with exquisite 



1 SB. Ak. TFien, Ixxxiii. 1881, pp. 289-376, pis. i.-vii. 

 2 Eev. Sci. Nat. Montpellier (3), ii. p. 470. 

 VOL. V 2 E 



