78 Mr. F. W. Uricli on Sericomyrmex opacus. 
a nest consists of two or three chambers which open on 
the original excavation. This is no longer used for grow- 
ing the fungus in, but forms a sort of antechamber 
which generally contains material brought in by the ants 
to grow their mushrooms on, which is deposited here and 
gradually made use of. The chambers adjoining are 
more or less round, with a diameter of about 2-3 inches, 
and any small roots of plants growing through them are 
not cut away but used by the ants to hang their mush- 
room gardens on. These fill the interior of the chamber 
and consist of a grey spongy mass consisting of a great 
number of little irregular cells and resembling a coarse 
sponge, amongst which are scattered larvae, pupas, and 
ants. The walls of the cells consist of small round 
pellets resembling dust shot and are penetrated by and 
enveloped in white fungus hyphae, which hold the mass 
together. Strewn thickly upon the surface of the garden 
are to be seen round white bodies about a quarter of a 
millimetre in diameter. These are what MoUer terms 
Kohlrabbi clumps, and consist of an aggregation of 
hyphae with spherical swellings on their ends. It is on 
this that the ants feed. The fungus found by Moller 
in the nests of the Brazilian fungus growers {Acromyrmex) 
is the Rozifes gongylophora, Moller, and if it is not the 
same species cultivated by S. opacus it is, at any rate, very 
nearly related to it. As material to grow their mushrooms 
on the ants make use of particles of fruit, flowers, and 
leaves, but prefer the fruit. They do well in artificial 
nests, constructed on Sir John Lubbock^s plan, and are 
easy to watch. I have tried them with all kinds of 
vegetable products; they have taken orange, banana, 
rose petals and leaves, and once they even made use of 
the dried glue from the back of an old book lying near 
their nest, but that day they had nothing else ; if the 
choice be left to them they invariably take fruit and seem 
to prefer the orange amongst these. Yery small particles 
of the white skin of the oranges are torn off, and, after 
undergoing a slight kneading process in the ants' man- 
dibles, are planted in the nest. The neuters are all of 
the same size, varying but slightly and never exceed 
4 mm. in length. They are more diurnal in their habits 
than other species of fungus growers, but also work a 
little at night. I have found winged forms in the nests 
in the month of July. 
