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as was first observed by Huber, their 1861 1866 1869 1872
their 1859 1860

excrete I watched them for some time through a lens, but not one excreted; I then tickled and stroked them with a hair in the same manner, as well as I could, as the ants do with their antennæ; but not one excreted. 1869
excrete. 1859 1860 1861 1866 1872

1 blocks not present in 1869; present in 1859 1860 1861 1866 1872
I watched them for some time through a lens, but not one excreted; I then tickled and stroked them with a hair in the same manner, as well as I could, as the ants do with their antennæ; but not one excreted.

solely for the 1869 1872
for the sole 1859 1860 1861 1866

there is no evidence 1861 1866 1869 1872
I do not believe 1859 1860

OMIT 1861 1866 1869 1872
in the world 1859 1860

OMIT 1869 1872
of a distinct 1859 1860 1861 1866

OMIT 1869 1872
in some few cases, 1859 1860 1861 1866

yielding
yielding,
as was first observed by Huber, their sweet excretion to ants: that they do so voluntarily, the
fol- lowing
following
facts show. I removed all the ants from a group of about a dozen aphides on a
dock- plant,
dock-plant,
and prevented their attendance during several hours. After this interval, I felt sure that the aphides would want to excrete I watched them for some time through a lens, but not one excreted; I then tickled and stroked them with a hair in the same manner, as well as I could, as the ants do with their antennæ; but not one excreted.
After- wards
Afterwards
I allowed an ant to visit them, and it immediately seemed, by its eager way of running about, to be well aware what a rich flock it had discovered; it then began to play with its antennæ on the abdomen first of one aphis and then of another; and
each
each,
aphis,
....
as soon as it felt the antennæ, immediately lifted up its abdomen and excreted a limpid drop of sweet juice, which was eagerly devoured by the ant. Even the quite young aphides behaved in this manner, showing that the action was instinctive, and not the result of experience. It is certain, from the observations of Huber, that the aphides show no dislike to the ants: if the latter be not
present,
present
they are at last compelled to eject their excretion. But as the excretion is extremely viscid, it is
probably
no doubt
a convenience to the aphides to have it removed;
and
....
therefore probably
the
they
aphides
....
do not
instinctively
....
excrete solely for the good of the ants. Although there is no evidence that any animal OMIT performs an action for the exclusive good of another OMIT species, yet each
species
....
tries to take advantage of the instincts of others, as each takes advantage of the weaker bodily structure of
others.
other species.
So
again,
again
OMIT certain instincts cannot be considered as absolutely perfect; but as details on this and other such points are not indispensable, they may be here passed over.
As some degree of variation in instincts under a state