Local Species 
strongly with the glossy black of his head, neck, 
and under parts. In summer the cocks of the 
two species grow more like one another owing to 
the wearing away of the outer edges of their 
feathers ; but it is always possible to distinguish 
between them at a glance. The two species 
meet at about the latitude of Bombay. Oates 
states that in a certain zone, from Ahmednagar 
to the mouth of the Godaveri valley, both 
species occur, and they do not appear to 
interbreed. 
It seems impossible to maintain that natural 
selection, acting on minute variations, has 
brought about the divergence between these 
two species. Even if it be asserted that the 
difference in the colour of the feathers of the 
back of the two cocks is in some way correlated 
with adaptability to their particular environment, 
how are we to explain the fact that in a certain 
zone both species flourish ? 
‘‘A similar phenomenon is furnished by the 
red-vented bulbul. This genus falls into several 
species, each corresponding to a definite locality 
and differing only in details from the allied 
species, as, for example, the distance down the 
neck to which the black of the head extends. 
There is a Punjab Red-vented Bulbul (AZodpastes 
intermedius), a Bengal (Molpastes bengalensis), a 
Burmese (Moffastes burmanicus), and a Madras 
(Molpastes hemorrhous) species. 
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