﻿EXTERNAL ANATOMY. WING FEATHERS. 87 



the tenth, is longer than any of the secondaries, and in 

 the giant humming-bird the secondary and tertiary 

 quills consist altogether of only six feathers ; the ter- 

 tials, in fact, may be termed as altogether obsolete. Per- 

 haps the most correct definition of the different powers 

 of flight in these two groups would be this, that the 

 swallows have the strongest, and the humming-birds, 

 while their flight lasts, the most rapid. The wing of 

 the giant humming-bird seems to be composed entirely 

 of primary quills, gradually, but regularly, diminishing 

 in size from the tip to the very end of the scapulars. 

 The exterior quill, although very strong, and much 

 more curved than the others, is, nevertheless, not very 

 typical of a falcated wing. The white-tailed black 

 species* is much more so, but the sickle-winged hum- 

 ming-birds {fig. 43.) are in this respect pre-eminent, for 

 not only are the three outer feathers greatly curved, but 

 their quills are unusually strong, dilated, and flattened : 

 there must be something very peculiar in the flight of 

 these latter, of which, at present, we are quite ignor- 

 ant. 



(80.) III. Pointed wings come nearest to those 

 which are more particularly termed acuminated, and 

 the passage from one to the other is marked by nume- 

 rous gradations, almost too refined for popular compre- 

 hension. Pointed wings may be divided under two sorts. 

 In the first, the outermost quill is either the longest, 

 or is nearly equal to the next one or two, but the 

 secondaries and tertials are of the ordinary length; that 

 is, they are two thirds as long as the primaries. This 

 is the leading distinction of the American genera Syl- 

 vicola, Setophaga, and Se'iurus.f A slight variation 

 from this proportion in the primaries is seen in the 

 parrots. In that common, but most beautiful, species 

 the Trichoglossus Swainsoni J, the first quill may be still 

 called as long as any of the others, although the second 



* Trochilus niger, Zool. 111. vol. i. pi. 82. 

 t North. Zool. vol. ii. p. 203. 



i Jardine and Selby, vol. ii pi. 111. See also Zool. 111. vol. ii. pi. 92. 

 G 4 



