8i6 THE POPULAR SCIENCE MONTHLY. 



mTELLIGEXCE OF ANTS. 



By GEORGE J. EOMANES. 

 II. 



IIIAYE now presented some of the most curious and interesting 

 facts concerning the intelligence of ants in general ; I shall next 

 proceed to state some of the more remarkable facts concerning the 

 intelligence of certain species of ants in particular. 



Leaf-cutting Ants of the Amazon. The mode of working prac- 

 ticed by these ants is thus described by Bates : 



They mount a tree in multitudes. . . . Each one places itself on the surface 

 of a leaf, and cuts with its sharp, scissors-like jaws a nearly semicircular incision 

 on the upper side ; it then takes the edge between its jaw^s, and by a sharp jerk 

 detaches the piece. Sometimes they let the leaf drop to the ground, where a 

 little heap accumulates, until carried oif by another relay of workers ; but gen- 

 erally each marches off with the piece it has operated on, and, as all take the 

 same road to the colony, the path they follow becomes in a short time smooth 

 and bare, looking like the impression of a cart-wheel through the herbage. 



Other observers have since said that this herbage is regularly felled by 

 the ants in order to make a road. Each ant carries its semicircular 

 piece of leaf upright over its head, so that the home-returning train is 

 rendered very conspicuous. Keener observation shows that this home- 

 returning, or load-carrying, train of workers keeps to one side of the 

 road, while the outgoing, or empty-handed, train keeps to the other 

 side ; so that on every road there is a double train of ants going in 

 opposite directions. When the leaves arrive at the nest they are re- 

 ceived by a smaller kind of worker, whose duty it is to cut up the pieces 

 into still smaller fragments, whereby the leaves seem to be better fitted 

 for the purpose to which, as we shall presently see, they are put. These 

 smaller workers never take any part in the out-door labor ; but they 

 occasionally leave the nest, apparently for the sole purpose of obtaining 

 air and exercise, for when they leave the nest they merely run about 

 doing nothing, and frequently, as in mere sport, mount some of the 

 semicircular pieces of leaf which the carrier-ants are taking to the 

 nest, and so get a ride home. 



From his continued observation of these ants Bates concludes and 

 his opinion has been corroborated by that both of Belt and Mtiller 

 that the object of all this labor is a highly remarkable one. The leaves 

 when gathered do not themselves appear to be of any service to the 

 ants as food ; but, when cut into small fragments and stored away in 

 the nests, they become suited as a nidus for the growth of a minute 

 kind of fungus on which the ants feed. We may therefore call these 

 insects " gardening ants," inasmuch as all their labor is given to the 

 rearing of nutritious vegetables on artificially prepared soil. They are 



