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doptera than at first, with the modern inductive method, the difference 
is remarkable, it is only during the last few years that specialists 
like Chapman, Comstock, Dyar, Hampson, Packard, and others, have, 
by adopting the theoretical method, made a distinct advance in this 
line of work. “ I take the view,” he says, “ that we have been waiting 
rather for method than for additions to the lists of species ; that we 
have hitherto too much disregarded the spirit of the speculative 
method in our taxonomic work, and that we have now, happily, found 
a band of workers who refuse to submit to the plea of inability, 
because all the existing species of Lepidoptera have not been collected 
and named.” In this I fully concur, and yet we must not be misled 
into the belief that all the work of our predecessors has been wasted, 
for there was a good deal of solid truth arrived at in their results, 
which our new methods have not essentially shaken. 
One other note, sounded by Professor Meldola, should not pass un¬ 
noticed. At the end of an appeal to practical workers to give more 
consideration to those who indulge in philosophic speculation, 
he urges the biological theorist to put forward his theories with 
more explicit caution than is necessary in the physical sciences, where 
experimental evidence is more easily obtainable. He urges this, 
because of “ the tendency on the part of the public to mistake 
tentative hypotheses for established theories.” No doubt in 
formulating this suggestion, Professor Meldola had in mind the 
ordinary educated public, not the purely entomological public. I 
would extend the learned Professor’s reason, and urge it, because a 
certain section of the entomological public often “ mistake tentative 
hypotheses for established theories.” It is impossible, either in this 
or any similar society, to open the most elementary discussion on 
mimicry or similar subjects without observing that the rank and file 
of entomologists are as apt as the ordinary public to run away with 
the mistaken notion that a tentative hypothesis meant to explain the 
facts, is intended as an established theory of the facts. It is an 
easy pitfall into which most of us are apt to fall. “ Moisture and 
Melanism ” is even now like holding a red rag at a bull, to some of 
our old conservative lepidopterists, and some of you will remember 
that when I first brought forward, a few years ago, the suggestion 
that moisture, smoke, etc., by darkening the surfaces on which insects 
rested, tended to produce melanochroism in certain insects that 
rested on such surfaces, by the influence of natural selection, and, 
further, that external factors (moisture, etc.) which acted on an insect 
prejudicially might produce physiological changes in the insect, 
resulting in the production of melanochroic aberrations, the ideas were 
scouted by a certain class of lepidopterists, who, by bringing forward 
special cases to which the hypotheses were never intended to apply, 
were unwilling to see in the idea a working hypothesis as to the 
explanation of the phenomenon in a large number of special cases. 
An exactly parallel line of objection was taken to the conclusions 
drawn from Merrifield’s early temperature experiments. Yet, these 
are likely now to take their placo as one of the most advanced pieces 
of work done in experimental entomological science during the present 
century. In this case, ignorance of the vital processes relating to 
histolysis, histogenesis and the formation of tho scales in the pupa, 
