68 MODERN PRACTICAL ANGLER. 
sibility of discriminating between different species, but 
often rendering it difficult for the fish even to identify 
the flies as flies. The only thing a fish can distinguish 
under these circumstances, besides the size of a fly, is its 
colour. We therefore regard form as a matter of com- 
parative indifference, and colour as all-important. 
Now in each of the above arguments there is a part 
that is sound and a part that is fallacious ; and it is from 
the failure in distinguishing the true from the false, 
that what I believe to be the erroneous practice of both 
these opposite parties springs. Each argument, however, 
is sound so far as to be an “unanswerable answer” to 
the other :—It is clear—as stated by the “ formalists’— 
that colour is zo¢ everything in a fly, because if it were, 
a bunch of coloured feathers tied on anyhow to the hook 
would kill as well as an artificial’ fly, whereas by their 
practice the colourists themselves. admit that such is not 
the case. On the other hand, the argument of the “colour- 
ists,” that from the way the artificial fly ts presented to the 
fish it is impossible they can distinguish mznutze of 
form and imitation, equally commends itself to common 
sense and common experience. This is the point, in 
fact, in which the entomological theory entirely breaks 
down. Because Trout take the artificial for the natural 
fly, the formalists argue that the one should be an exact 
counterpart of the other, ignoring the fact that the two 
insects are offered to the fish under entirely different 
conditions. The artificial fly is presented under water 
