152 WILLIAM MORTON WHEELER. 



and from their peculiar raised entrance can readily be recognized. 

 They are always excavated in clayey soil, and the raised entrances, 

 which are more or less cylindrical, are constructed with the 

 particles of earth resulting from their mining operations and are 

 about an inch in height. In young colonies this entrance leads 

 into a small chamber, about six inches below the surface of the 

 ground, situated, not at the end of the gallery but either to the 

 left or right of it. As the colony increases the ants do not enlarge 

 this original chamber, but, piercing its side, form another chamber 

 near it with a small entrance hole. In large colonies, which never 

 consist of more than about 200 individuals, a nest consists of two 

 or three chambers which open on the original excavation. This 

 is no longer used for growing 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 mushroom gardens on. These fill the interior 

 of the chamber and consist of a gray spongy mass consisting of a 

 great number of little irregular cells and resembling a coarse 

 sponge, amongst which are scattered larvae, pupae, 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 millimeter in diameter. These are what Moller terms "Kohl- 

 rabi" 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 Rozites 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 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 



