ground below. Their innumerable long legs looked like brown threads
binding together the mass, which must have been at least a cubic
yard in bulk, and contained hundreds of thousands of individuals,
although many columns were outside, some bringing in the pupae of
ants, others the legs and dissected bodies of various insects. I
was surprised to see in this living nest tubular passages leading
down to the centre of the mass, kept open just as if it had been
formed of inorganic materials. Down these holes the ants who were
bringing in booty passed with their prey. I thrust a long stick
down to the centre of the cluster, and brought out clinging to it
many ants holding larvae and pupae, which probably were kept warm
by the crowding together of the ants. Besides the common
dark-coloured workers and light-coloured officers, I saw here many
still larger individuals with enormous jaws. These they go about
holding wide open in a threatening manner, and I found, contrary to
my expectation, that they could give a severe bite with them, and
that it was difficult to withdraw the jaws from the skin again.

One day when watching a small column of these ants, I placed a
little stone on one of the ants to secure it. The next that
approached, as soon as it discovered the situation of the prisoner,
ran backwards in an agitated manner, and communicated the
intelligence to the others. They rushed to the rescue, some bit at
the stone and tried to move it, others seized the captive by the
legs, and tugged with such force that I thought the legs would be
pulled off, but they persevered until they freed it. I next covered
one up with a piece of clay, leaving only the ends of its antennae
projecting. It was soon discovered by its fellows, which set to
work immediately, and by biting off pieces of the clay, soon
liberated it. Another time I found a very few of them passing along