Food of the Ants 65 
masses of ant-food spread about, the ants are in great con- 
cern 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. That they do 
not eat the leaves themselves I convinced myself; for I 
found near the tenanted chambers, deserted ones filled with 
the refuse particles of leaves that had been exhausted as 
manure for the fungus, and were now left, and served as food 
for larvee of Staphylinide and other beetles.1 
These ants do not confine themselves to leaves, but also 
carry off any vegetable substance that they find suitable for 
growing the fungus on. They are very partial to the inside 
white rind of oranges, and I have also seen them cutting up 
and carrying off the flowers of certain shrubs, the leaves of 
which they neglected. They are particular about the venti- 
lation of their underground chambers, and have numerous. 
holes leading up to the surface from them. ‘These they open 
out or close up, apparently 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 
1 This theory that the leaf-cutting ants feed on a fungus which they 
cultivate has been confirmed by Mr. Fritz Miillar, who had arrived at 
it independently in Brazil. His observations on this and various other 
habits of insects are contained in a letter to Mr. Charles Darwin, pub=- 
lished in Nature of June 11, 1874. 
