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ON THE CLASSIFICATION OF BIRDS. 



themselves round the base of the lower mandible, as if 

 to defend the mouth in all directions ; but we do not 

 at this moment remember any other birds with a similar 

 formation. These appendages being found only in 



these bristles cannot be found, because the insects they 

 live upon, being very small, are swallowed without any 

 difficulty, and are incapable of making any struggles ; 

 but the case is far different with those captured by 

 the night-jars, whose chief sustenance is derived from 

 coleopterous insects which fly in the evening, and whose 

 hard legs and bifurcated claws might inflict much 

 injury in their struggles to escape. Now, the bristles 

 we are describing, are more developed in this tribe of 

 birds than in any of those which feed upon the wing ; 

 and they obviously answer two purposes, — they protect 

 the angles of the mouth from any injury, while at the 

 same time they confine the struggles of the captive 

 insect. In the genuine flycatchers, these bristles are 

 rather less developed ; although in some few, as in the 

 genus Megalophus* , they are very long : but then, on the 

 other hand, the Muscicapince never, or very rarely, feed 

 upon coleopterous insects, but seem to confine them- 

 selves to those whose bodies are soft ; yet, as the wings 

 of these latter are often large, the bristles are necessary 

 to confine their fluttering. It is rather singular that 

 the woodpeckers, which feed upon coleopterous insects, 

 as well as soft larva, are destitute of these bristles; but 

 we may observe that the feathers round the mouth are 

 remarkably thick and compact, and that the nostrils are 



such birds as feed 

 upon insects, and 

 chiefly in those which 

 catch their prey on 

 the wing, leaves us in 

 no doubt as to their 

 specific use. Among 

 the swallows, indeed, 



* Megalopkus regins, Brazilian Birds, pi. 51, 52. 



