The Making of Species 
hens, as, for example, the paradise fly-catcher 
(Terpsiphone paradist), the showy cock shares 
the burden of incubation equally with the hen. 
It frequently happens that allied species of 
birds are found in neighbouring countries. The 
Indian robins, for example, fall into two species. 
The brown-backed robin ( 7hamnobta cambayensis) 
occurs north of Bombay, while the black-backed 
species (7. fudicata) is found south of Bombay. 
The hens of these two species are almost indis- 
tinguishable, but the cocks differ, in that one has 
a brown back, while the other’s back is glossy 
black. The Wallaceian theory of colouration 
seems quite unable to explain this phenomenon— 
the splitting up of a genus into local species— 
which is continually met with in nature. Equally 
inimical to the theory of protective colouration is 
the existence, side by side, of species which 
obtain their living in much the same manner. 
On every Indian lake three different species of 
kingfisher pursue their profession cheek by 
jowl; one of these—Ceryle rudis—is speckled 
black and white, like a Hamburg fowl; the 
second is the kingfisher we know in England; 
and the third is the magnificent white-breasted 
species—Talcyon smyrnensis—a bright-blue bird 
with a reddish head and a white wing bar. It is 
obvious that all three of these diversely plumaged 
species cannot be protectively coloured. It may 
perhaps be objected that the piscatorial methods 
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