1877. ] Is Mimicry Due to Natural Selection ? 5 
fore, it can be shown that species which would be called * imi- 
tating and imitated” if they occurred together are in reality 
found widely separated, it is obvious that this would materially 
weaken Miiller’s argument. Whether this is the case with Lep- 
idoptera, I have not sufficient knowledge to state; but that ac- 
complished entomologist, the late Mr. Edward Newman, assured 
me that in the case of some of the most remarkable instances of 
such resemblance known in this country, between particular 
species of Diptera and particular species of Hymenoptera, the 
resemblance is not associated with geographical contiguity. In 
the case of plants, at all events, I am prepared to state that re- 
semblances as striking, which would certainly be considered illus- 
trations of mimicry if they were found together and were of any 
apparent utility, do occur between species widely separated in 
space. 
In the number of the Popular Science Review for January, 
1872, appeared an article entitled Mimicry in Plants, in which 
I gave a number of illustrations of plants, or parts of plants, be- 
longing to species widely separated according to any natural sys- 
tem of classification, and yet so exactly alike in their vegetative 
organs that they would deceive a practiced botanist. The resem- 
blance extends in some instances not merely to general habit 
and appearance, but even to the arrangement of the veins. Dr. 
Berthold Seemann, no mean authority, speaks of having met in 
the Sandwich Islands with a variety of Solanum Nelsoni, which 
looked for all the world like Zhomasia solanacea of New Hol- 
land, a well-known Buttuereaceous plant of our gardens, the re- 
semblance between these two widely separated plants being quite 
as striking as that pointed out in Bates’s Naturalist on the 
Amazon “ between a certain moth and a humming-bird.”? In 
no one instance, that I am aware of, in the vegetable kingdom 
has protective mimicry been suggested as an explanation of this 
homoplasm. In most cases, as the one recorded above, the 
plants in question do not grow in contiguity. 
But a more serious objection to the theory, that these remark- 
able resemblances are brought about by natural selection acting 
in the way indicated by Bates and Müller, lies in the difficulty 
of understanding how the first steps in the approach of one 
insect towards another could possibly be useful in deceiving an 
enemy. All the most cautious advocates of the theory, includ- 
ing Mr. Darwin himself, admit that “ natural selection acts with 
1 Gardener’s Chronicle, June 27, 1868. 
