two or three bristles, serve the same purpose. Further, in 

 the case of the bee it will be found that the fore-wing, when at 

 rest, is folded longitudinally back upon itself. 



Finally, turn to the flies. Herein it will be seen that 

 there is but a single pair of wings, the hind pair having become 

 reduced to mere stumps, known as " balancers." 



Much, very much more, might have been said of these 

 wings : but our conversation is of birds. We cannot, how- 

 ever, properly appreciate either the essential characters of 

 their wings, or their flight, without some such standards of 

 comparison as is afforded by the wings of other creatures. 



II 



