402 MOTACILLID &. 
that of the White Wagtail throughout its whole length 
from the point to the more dilated base, and that while our 
pied bird changes on the back from ash grey to black in the 
breeding-season, the back of the white bird remains as 
light in colour as it is in winter; even the back of the 
female of our pied bird changes, and is decidedly much 
darker in summer than the back of the White Wagtail at 
the same season. 
The vignette represents the appearance of the Pied Wag- 
tail in summer and winter. 
