6 Is Mimicry Due to Natural Selection? (January, 
? 
extreme slowness;” and again that “only those variations 
which are in some way profitable will be preserved or naturally 
selected.” By a train of reasoning founded on these two prem- 
ises, I attempted to show, in a paper on The Theory of Natural 
Selection from a Mathematical Point of View! read before the 
British Association at the Liverpool meeting in 1870, that the 
chances against the required amount of change being brought 
about by this agency solely, are, on a hypothesis most favorable 
to the theory, say ten million to one; and I am not aware that 
the arguments there used have been met. Again, the purpose 
‘of mimicry is generally stated to be the perpetuation of the 
imitating insect, in consequence of deceiving its natural enemies 
by its resemblance to some species distasteful to them. If so, 
the purpose seems to have been somewhat inadequately fulfilled, 
even by the most perfect mimetism, as Mr. Bates and Mr. Wal- 
lace agree in stating, that, both in South America and the Malay 
Archipelago, the imitating species are always confined to a lim- 
ited area, and are always very scarce compared with the imitated 
species. 
Mr. Wallace, in his address to the British Association alluded 
to above, lays great stress on the probable influence of local 
conditions on the coloring and other external markings of ani- 
mals, dependent on laws of which we are at present almost en- 
tirely ignorant. ‘There can be little doubt that the instances of 
close resemblance in the vegetable kingdom of which I have 
spoken are due entirely to similarity of external conditions. 
When, therefore, we find similar phenomena in the animal world, 
it would appear more reasonable to attribute them to similar 
causes, rather than to refer them entirely to a hypothetical proc- 
ess like that of natural selection acting through protective 
mimicry, in which we are unable actually to follow two consecu- 
tive steps. 
Mr. Mivart, in his Genesis of Species, and Mr. J. J. Mur- 
phy in his Habit and Intelligence have argued, much more 
forcibly than I can do, against the adequacy of natural selection 
to account for the phenomena in question ; and, lest it may be 
thought that I am opposing the united view of all our best nat- 
uralists, I may remind my readers that so uncompromising an 
advocate of the theory of evolution as Professor Huxley has 
stated his deliberate conviction ‘after much consideration, and 
with assuredly no bias against Mr. Darwin’s views, that, as the 
1 Nature, vol. iii, page 30, November 10, 1870. 
