IIUMMING-BIRDS. 
Ill 
under the denomination of sickle or sabre-winged 
humming-birds, and forming the genus Campylopterus 
of Swainson, they are developed to an extraordinary 
degree at the base, and nearly equal the breadth of 
the plume. 
The birds composing this division are large, but not 
the largest of the family ; and our present information 
of their habits does not point out any peculiarity to 
which this development is adapted. It, besides, is 
wanting, or in a great measure reduced, in the females 
of some of them. Mr Swainson has figured two birds, 
which seem almost identical, except in the absence of 
the broad shaft in the one \ and in specimens of the 
sabre-wing, which we have figured at Plate XXXIV, 
the shafts of the female bird were in breadth only 
about one-half. 
The organ of next importance, as directing the flight, 
is the tail. This is always powerful, and presents 
every modification which we find in those birds 
endowed with powerful or rapid flight, and will be of 
use to the systematist in directing the forms which 
present themselves in analogy with the other families 
