278 



ENTOMOLOGY 



ants may be seen, one carrying their leafy burdens toward the nest, the 



other returning for more plunder. 



The use made of these leaves has been 

 the subject of much discussion. Belt found 

 the true explanation, but it remained for 

 Moller to investigate the subject so thorough- 

 ly as to leave no room for doubt. The ants 

 grow a fungus upon these leaves and use it 

 as food. The bits of leaves are kneaded into 

 a pulpy, spongy mass, upon which the fungus 

 at length appears. The food for the sake of 

 which the ants carry on their complex opera- 

 tions consists of the knobbed ends of fungus 

 threads (Fig. 289), and these bodies, rich in 

 fluid, form the most important, if not the 

 sole food of the leaf-cutting ants. By assidu- 

 ously weeding out all foreign organisms the 

 ants obtain a pure culture of the fungus, and 

 by pruning the fungus they keep it in the 

 vegetative condition and prevent its fructi- 

 fication; under exceptional circumstances, 

 however, the fungus develops aerial organs 

 of fructification of the agaricine type, but 



this species (Rozites gongylophora) has never been found outside of ants' 



nests. The peculiar clubbed threads 



were produced by Moller in artificial 



cultures and are not spores, but prod- 

 ucts of cultivation. Other ants are 



known to cultivate other kinds of fungi 



for similar purposes. 



McCook has found a leaf-cutting 



ant (Alia fervens) in Texas, and men- 

 tions that it cuts circular pieces out 



of leaves of chiefly the live-oak, these 



being dropped to the ground and taken 



to the nest by another set of workers. 



He records an underground tunnel of 



Alia fervens which extended 448 feet 



from the nest and then opened into a 



path 185 feet in length; the tunnel was 18 inches below the surface on an 



FIG. 288. A, B. cuts made 

 in Cupliea leaves in four or five 

 minutes by Atta discigera; 

 natural size. C, Atta dis- 

 cigera transporting severed 

 fragments of leaves; reduced. 

 After MOLLER. 



FIG. 289. Fungus clumps (Rozites 

 gongylophora) cultivated by ants of the 

 genus Atta. Greatly magnified. After 

 MOLLER. 



