THE COLORATION PROBLEMS. 219 
I should, however, take the most particular care to keep questions 
of fact as opposed to theory abundantly distinct. Hence I should 
never (as Mr. Wheeler surmises I should not) fall into the trap of con- 
sidering that the melanic forms of our cities were a ‘“‘ Mullerian” 
assemblage. A slight investigation of the facts would show that the 
salient feature of Millerian mimicry, as I understand it to be, is 
absent, viz., a proved or reasonably presumed distastefulness common 
to the assemblage. I do not understand, nor do I mean to claim, by 
universality of application, that because moths A, B, C, and D are 
black, and occur in a given locality together, and might if they were 
moderately distasteful be a Miillerian assemblage, therefore that, with- 
out proot of the existence of the peg on which the whole thing hangs, 
they must be assumed to be a Mullerian group. 
Again, with regard to those cases where the dampness of localities 
have produced melanism, it is a matter for investigation. It seems to 
me, that if one carelessly abstains from investigation and assumes that 
the darkness is due of itself to the process of elimination, one is assum- 
ing without evidence a whole array of essential facts, which must be 
shown to exist before the theories can reasonably be expected to operate. 
Moreover, it is often next to impossible to aseertain to what extent the 
operation of one natural law is masked, retarded, or accelerated by the 
operation of another. Correlation of parts, etc., in this respect is one 
of the greatest pitfalls. One never knows what effect a modification 
in one respect may produce in another, and a careful perusal of ‘“‘ The 
Determination of Sex”’ (Doncaster), will demonstrate to the thought- 
ful reader how characters are so wedded to one another that the absence 
of one may necessitate the absence of another. 
Another point that has to be borne in mind is this, a variation 
started under one natural law, may come under the operation of a 
second, or a third, so what started as a pure sport may become a 
mimic. 
What I meant to express by my claim for universality of applica- 
tion was something a great deal more like this. Where moth A sits 
upon the trunk of an oak in company with spider B, beetle C, and 
caterpillar D, and all resemble the bark, whilst another group, moth HE. 
caterpillar F, spider G, and beetle H, live among the leaves of the same 
tree, which leaves they likewise resemble, then the same law applies 
to the one group as applies to the other. 
Besides that claim I also intended to claim that if the first group 
occurred in Britain and the second in Timbuctoo, the same law applied 
to both groups. 
Moreover, I intended to claim as well that the theory must cover 
such a case as that of Hypolimnas misippus wherever it occurred, and 
for that purpose I refer to what I said at vol. xxv., pp. 150 and 153, 
because the coloration of H. misippus at Bipindi, Cameroons (thank 
goodness we need no longer spell it ‘‘Kamerun’”’!), is explained 
reasonably by the Coloration theories, and likewise in Ceylon, whilst 
Col. Mander’s atmospheric explanation is out of court in the 
Cameroons. ; 
No doubt, if I leave H. misippus at this point, someone will 
promptly enquire how do I get over the difficulty of the recent exten- 
sion of this insect to the Neotropical Zone. In reality this presents 
no difficulty, the insect had by the time it reached that region an 
