See page in:
1859
1860
1861
1866
1869
1872

Compare with:
1859
1860
1861
1869
1872

parents, 1859 1860 1861 1866
ants or parents, 1869 1872

jaws having a 1859 1860 1861 1866 1869
OMIT 1872

simultaneously 1859 1860 1861 1866 1872
at the same time 1869

OMIT 1866 1869 1872
from being the most useful to the community, 1859 1860 1861

OMIT 1866
in greater and greater numbers 1859 1860 1861
in greater and greater numbers, 1869 1872

in greater and greater numbers, until 1866
until 1859 1860 1861 1869 1872

at the same time and place 1866
OMIT 1869 1872

I have now explained how, 1866 1869 1872
Thus, 1859 1860 1861

and in the form and number of the teeth. But the important fact for us is,
that
that,
though the workers can be grouped into castes of different sizes, yet they graduate insensibly into each other, as does the widely-different structure of their jaws. I speak confidently on this latter point, as
Mr.
Sir J.
Lubbock made drawings for
me
me,
with the camera
lucida
lucida,
of the jaws which I
had
....
dissected from the workers of the several sizes. Mr. Bates, in his
most
most
interesting 'Naturalist on the Amazons,' has described
some
some
analogous cases.
With these facts before me, I believe that natural selection, by acting on the fertile parents, could form a species which should regularly produce neuters,
either
either
all of large size with one form of jaw, or all of small size with jaws having a widely different
jaws;
structure;
or lastly, and this is
the
our
climax of difficulty, one set of workers of one size and structure, and simultaneously another set of workers of a different size and structure;— a graduated series having
first been
been first
formed, as in the case of the driver ant, and then the extreme
forms,
forms
OMIT having been produced OMIT through the
survival
natural selection
of the parents which generated
them;
them,
in greater and greater numbers, until none with an intermediate structure were produced.
An analogous explanation has been given by Mr. Wallace, of the equally complex case, of certain Malayan
butterflies
Butterflies
regularly appearing at the same time and place under two or even three distinct female forms; and by Fritz
Müller,
Müller,
of certain Brazilian crustaceans likewise appearing under two widely distinct male forms. But
this
the
subject need not here be discussed.
I have now explained how, as I believe, the wonderful fact of two distinctly defined castes of sterile workers existing in the same nest, both widely different from each other and from their parents, has originated. We