ley debouching out of Huerfanos
Park, a government reservation, I believe, at that time. The nest was
situated on the sandy shore of a small creek, and was a perfect square
of three or four feet, from which all grass, weeds, etc., had been
carefully removed. Around three sides of this square, viz., north, east,
and west, a column of black soldier ants continually patrolled night and
day.

Near the southeast corner of this open space the entrance to the nest
was situated. The south side of the square was not guarded, but was left
open for the entrance and exit of the hundreds of dark yellow workers
which were engaged in bringing food to the village. No sooner was a
burden put down than it was seized by black workers, which then carried
it into the nest. At no time did I see a black worker bringing food to
the centre of the square, nor did I ever see a yellow worker carrying
food into the nest; the blacks and the yellows never interfered with one
another's business.

To test the reasoning powers of these ants, I partially disabled a
centipede and threw it into the square a short distance from the patrol
line. For a moment or two the line was broken by the warriors hurrying
out to do battle with the squirming intruder. But only for a moment or
two, for orders were issued by some ant in authority (so it seemed, and
so I believe), and the line was established, though somewhat thinned by
the absence of soldiers. The messenger was sent to headquarters and
reenforcements were sent out, and soon the line was as strong as ever,
though hundreds of soldiers were warring with the centipede. The latter
was soon killed, and its body was removed piecemeal by the yellow
workers, which carried the fragments far beyond the boundaries of the
square.

Again, with my hunting-knife I dug a deep trench across the border of
one side of the square. The ants seemed dazed at first, but rapidly
adapted themselves to their new surroundings. They extended their patrol
line until it embraced the entire trench; then a countless horde of
yellow workers went to work, and in a day's time filled up the deep
excavation level with the surrounding surface! The patrol was then
reestablished on the old line as though nothing had occurred to
interrupt the ordinary routine of the colony. Before leaving the valley
I dug up the nest and examined the peculiar individuals whose enforced
habits give to these interesting ants the name of "honey-makers." Each
one of