284 SYLVIADA. 
specimens, some changing more rapidly than others; but 
the change from grey to brown produced by the autumn 
moult is rapid and general, affecting all alike. 
Females and young birds in autumn do not differ much 
from adult males at the same season, except that the mark- 
ings about the head are less clearly defined, and the colours 
are rather less pure. The birds are in this state of plumage 
when caught in such numbers on the south downs. 
The vignette represents the breastbones of the Robin 
and the Wheatear. 
