29 THE STORY OF THE BIRDS. 
In the very young birds these often give the frock 
the appearance of having a V-shape front and back— 
a thing pardonable enough in a baby, but which is 
decently covered up by the overlapping of the feath- 
ered tracts as the bird grows older. Bare skin is 
used as ornament in adult birds, as well as in the 
ballet and the best society, but always modestly on 
the extremities of feet or head. In fact, as we come 
up higher among birds, where monogamy, gallantry, 
devotion, and decency prevail, we do not find it at 
all—the oscines, or prima donnas in feathers, in no 
sense needing the décolleté to make them attractive. 
Even the bare space in the back is wanting here. 

: q : : 
De 151 
pf 
Feather tracts (after Coues). 
Lower surface of a swift, showing Upper surface of a swift, showing 
tracts and bare spaces on ab- the forking of feather tracts on 
domen, neck, ete. back, ete. 
Besides these two bare tracts there are many others. 
Some of those extending upon the neck are very 
helpful also in showing the kinship of birds. 
Among the birds of the group known as the 
Picarve, where the yoke-toes and other abnormalities 
