852 The American Naturalist. [September, 
each genus grow a different sort, one kind only, and stubbornly refuse 
to eat any other, preferring to starve. More curious still, under the 
zealous attention of these little gardeners a special form of the fungus 
has been developed in much the same way that human selection has de- 
veloped choice cabbages and cauliflowers out of what were originally 
quite ordinary sorts. This form of the fungus consists of groups of 
swollen hyphe-ends, called Kohlrabi tufts. The greater part of the 
book deals with the fungous gardens of species of the genus Atta. The 
garden occupies the center of each nest as a loose, sponge-like mass, 
consisting of leaf-fragments held together by fungous threads. These 
gardens are often of large size, but between them and the walls of the 
nest there is always an open space. In the sponge-like cavities of these 
gardens the ants live, place their eggs, and rear their young. Often 
the eggs and sometimes the larve are overgrown and fastened together 
by the fungus, so that many as a hundred eggs may be seized and car- 
ried away by a single ant without inconvenience. The well known 
care that ants bestow on their progeny makes it certain that this plac- 
ing the eggs in groups and allowing them to be bound together by the 
fungus is not simply accidental. When the nest is broken open and its 
contents scattered, or when the colony migrates, every tiny fragment of 
the fungous garden is gathered up and removed as carefully, and with 
as much solicitude as are the young. These fragments are rapidly and 
skillfully built into a new garden in the old nest or in some other place. 
Leaves are cut from a great many sorts of plants and often in such 
quantities as to entirely defoliate them, but are never eaten even to pre- 
vent starvation. Their sole food is the fungus which they cultivate, 
éven fruits and starchy foods being used exclusively as a substratum 
for growing this much-beloved fungus. The leaf fragments brought 
into the nest are bitten and trimmed into smaller pieces and these are 
squeezed and kneeded into tiny pellets which are then carefully patted 
into the walls of the garden, and are overgrown by the fungus in a few 
hours. Exhausted fragments are thrown out and fresh pellets put in 
wherever needed by the fungus. Old worn-out masses of mycelium are 
also thrown out of the nest. Upon a special class of the colony, dis- 
tinguished from the leaf cutters by their smaller size, devolves the task 
of weeding the garden and keeping it pruned within bounds. When 
neglected for a single day, i. e., by the removal of most or all of the 
ants, innumerable fungous threads shoot out into the air in every di- 
rection, and the well-kept garden soon becomes an unmanagable and 
uninhabitable thicket. When only a few ants are left in such a nest they 
work desparately, night and day, to keep it in order, but seem to know 
