to keep up a regular degree of temperature below.  The great care they take that the pieces of leaves they carry into the nest should be neither too dry nor too damp, is also consistent with the idea that the object is the growth of a fungus that requires particular conditions of temperature and moisture to ensure its vigorous growth.  If a sudden shower should come on, the ants do not carry the wet pieces into the burrows, but throw them down near the entrances.  Should the weather clear up again, these pieces are picked up when nearly dried, and taken inside; should the rain, however, continue, they get sodden down into the ground, and are left there.  On the contrary, in dry and hot weather, when the leaves would get dried up before they could be conveyed to the nest, the ants, when in exposed situations, do not go out at all during the hot hours, but bring in their leafy burdens in the cool of the day and during the night.  As soon as the pieces of leaves are carried in they must be cut up by the small class of workers into little pieces.  I have never seen the smallest class of ants carrying in leaves! their duties appear to be inside, cutting them up into smaller fragments, and nursing the immature ants.  I have, however, seen them running out along the paths with the others; but instead of helping to carry in the burdens, they climb on the top of the pieces which are being carried along by the middle-sized workers, and so get a ride home again.  It is very probable that they take a run out merely for air and exercise.  The largest class of what are called workers are, I believe, the directors and protectors of the others.  They are never seen out of the nest, excepting on particular occasions, such as the migrations of the ants, and when one of the working columns or nests is attacked, they then come stalking up, and attack the enemy with their strong jaws.  Sometimes, when digging into the burrows, one of these giants has unperceived climbed up my dress, and the first intimation of his presence has been the burying of his jaws in my neck, from which he would not fail to draw blood.  The stately observant way in which they stalk about, and their great size, compared with the others, always impressed me with the idea that in their bulky heads lay the brains that directed the community in their various duties.  Many of their actions, such as that I have mentioned of two relays of workmen carrying out the ant food, can scarcely be blind instinct.  Some of the ants make mistakes, and carry in unsuitable leaves.  Thus grass is always rejected by them, but I have seen some ants, perhaps young ones, carrying leaves of grass; but after a while these pieces are always brought out again and thrown away.  I can imagine a young ant getting a severe ear-wigging from one of the major-domos for its stupidity.

[Illustration:  SECTION THROUGH LEAF-CUTTING ANT’S NEST.]

I shall conclude this long account of the leaf-cutting ants with one more instance of their reasoning powers.