sufficient proof that wherever it has arisen it has been preserved;
and further, that even the highly complex forms of galls are
evolved from forms so simple that we hesitate to call them galls at
all[66].

[66] _Entomologist_, March, 1890.

The paper then proceeds to give a number of individual cases. No doubt
the principal objection to which Mr. Cockerell's hypothesis is open is
one that was pointed out by Herr Wetterhan, viz. "the much greater
facility afforded to the indirect action through insects, by the
enormously more rapid succession of generations with the latter than
with many of their vegetable hosts--oaks above all[67]." This
difficulty, however, Mr. Cockerell believes maybe surmounted by the
consideration that a growing plant need not be regarded as a single
individual, but rather as an assemblage of such[68].

[67] _Nature_, vol. xli, p. 394.

[68] _Ibid._ vol. xli, pp. 559-560.

NOTE C TO PAGE 394.

The only remarks that Mr. Wallace has to offer on the _pattern of
colours_, as distinguished from a mere _brilliancy of colour_, are added
as an afterthought suggested to him by the late Mr. Alfred Tylor's book
on _Colouration of Animals and Plants_ (1886). But, in the first place,
it appears to me that Mr. Wallace has formed an altogether extravagant
estimate of the value of this work. For the object of the work is to
show, "that diversified colouration follows the chief lines of
structure, and changes at points, such as the joints, where function
changes." Now, in publishing this generalization, Mr. Tylor--who was not
a naturalist--took only a very limited view of the facts. When applied
to the animal kingdom as a whole, the theory is worthless; and even
within the limits of mammals, birds, and insects--which are the classes
to which Mr. Tylor mainly applies it--there are vastly more facts to
negative than to support it. This may be at once made apparent by the
following brief quotation from Prof. Lloyd Morgan:--

It can hardly be maintained that the theory affords us any adequate
explanation of the _specific_ colour-tints of the humming-birds, or
the pheasants, or the Papilionidae among butterflies. If, as Mr.
Wallace argues, the immense tufts of golden plumage in the bird of
paradise owe their origin to the fact that they are attached just
above the point where the arteries and nerves for the supply of the
pectoral muscles lea