The Making of Species 
by birds, although he observed on other occasions 
some isolated cases. 
This appears to be the sum total of the 
evidence adduced by Professor Poulton as 
regards the capture of butterflies by birds. 
This seems to us an altogether insufficient 
foundation upon which to build. the theory that 
the cases of resemblance between unrelated 
species have been effected by natural selection. 
It is, however, to be noted that probably 
among birds the most dangerous enemies of 
butterflies are not those that habitually catch 
insect prey on the wing. Such are experts in 
the art of fly-catching, and would despise the 
comparatively meatless butterfly. One often 
comes across butterflies with an identical notch 
in each wing, which leaves little room for doubt 
that those particular butterflies had been snapped 
at, whzle resting, by a bird. Among birds the 
chief enemies of butterflies and moths are pro- 
bably to be found in those that hunt for their 
food in bushes and trees. 
Thus, what we do know of the nature of the 
struggle for existence offers but poor support to 
the Neo-Darwinian- explanations of the cases of 
so-called mimicry in nature. 
Professor Poulton’s idea of pitting the argu- 
ment of hypertely against that of the alleged 
supreme sharp-sightedness of birds is ingenious, 
but is not likely to satisfy very many people save 
240 
