INTRODUCTION. 



Acuminated wings are those adapted for the most rapid and 

 long-continued flight. In wings of this description the first quill 

 is generally the longest, although it sometimes happens that 

 there is scarcely any perceptible difference between that and the 



Fig. 3.- AcLT.iiNATED Wixc— Swallow. 



second ; the rest, however, rapidly diminish at almost equal in- 

 tervals, until they reach the lesser quills, which are little more 

 than one-third the length of the exterior primaries. 



It is obvious that in wings of this description nearly the whole 

 power of the stroke is thrown into the primary quills, which are 

 those principally employed in flight. 



Falcated or Sword-shaped wings are only possessed by 

 the Humming-Birds. In these, the two or three primaries are 

 curved towards the ends, which are rather suddenly rounded off, 

 while all the succeeding ones are straight. 



Fig. 4. — Falcated Wing of Humming-Bird. 



Pointed wings come nearest to those termed acinninatcd, 

 and the passage from one of these forms to the other is suscep- 

 tible of numerous gradations, almost too refined for popular 

 explanation. 



Pointed wings may be divided into two sorts. In the first, 

 the outermost quill is either the longest, or nearly equal to the 

 next one or two ; but the secondaries and the tertiaries are of 

 the ordinary length — that is, they are two-thirds as long as the 

 primaries. 



In the second description of pointed wing the first quill is 



