42 BIRDS OF LA PLATA 
The little Bank-Martin disappears immediately 
after the Purple Martins. Many stragglers continue 
to be seen after the departure of the main body ; but 
before the middle of March not one remains, the 
migration of this species being very regular. 
WHITE-CAPPED TANAGER 
Stephanophorus leucocephalus 
Uniform deep blue; cap silvery white with a small crimson crest 
above the forehead ; length 7 inches. Female less bright. 
THis beautiful bird is one of the three species of 
Tanager which range south as far as Buenos Ayres. 
The Tanagers are, however, a numerous family 
(Tanagridz), numbering about 400 species, mostly 
restricted to the forest-clad regions of Central and 
South America, between the tropics. They are an 
American family nearly related to the Finches, and 
the relationship is so close in at least one genus as to 
make it difficult for naturalists to determine its true 
place—whether in the Finch or Tanager family. In 
form they resemble Buntings and do not vary greatly 
in size; of the greater number it may be said that 
they are about as big as a Yellow or a Corn Bunting. 
But in their colouring they have diverged widely 
from their relations—the family they spring from as 
we must suppose. There are many bright-coloured 
Finches, but with a few rare exceptions they do not 
