When a nest is disturbed and the masses of ant-food spread about, the ants are in great concern to carry every morsel of it under shelter again; and sometimes, when I had dug into a nest, I found the next day all the earth thrown out filled with little pits, that the ants had dug into it to get out the covered-up food. When they migrate from one part to another, they also carry with them all the ant-food from their old habitations. In Büchner's 'Geistesleben der Thiere' there is published an interesting description of the habits of these ants, which was communicated to the author by Dr. Fr. Ellendorf of Wiedenbrück, who has lived many years in Central America. Dr. Ellendorf says that-- It would be quite impossible for them to creep even through short grass with loads on their heads for miles. They therefore bite off the grass close to the ground for a breadth of about five inches, and throw it on one side. Thus a road is constructed, which is finally made quite smooth and even by the continual passing to and fro of millions upon millions night and day. . . . If the road is looked down upon from a height with these millions thickly pressed together, and all moving along with their green bannerets over their heads, it looks as though a giant green snake were gliding slowly along the ground; and this picture is all the more striking in that all these bannerets are swaying backwards and forwards.[33] This observer made the experiment of interrupting the advance of a column of these ants, with the interesting result which he describes:--