Life in La Plata 235 



have more intelligence on the average than any other 

 order of insects. Ever since the days of Solomon this 

 fact has been recognized. It would require a large 

 volume to relate what has already been learned as to 

 the habits of these tiny creatures in South American 

 lands, and the field has only been partially investigated. 

 I was much interested in the ways of one species of ant, 

 which is quite common in Argentina, and which has for 

 ages been engaged in growing mushrooms. They are 

 commonly known as 'leaf -cutting ants.' On a num- 

 ber of occasions I found them at work. They construct 

 great underground galleries or cellars deep in the earth. 

 Into these they carry masses of bits of green foliage, 

 which they pile up in thick layers. In the beds of 

 vegetable compost, which they thus construct, are 

 implanted the spawn of certain fungi, which in the 

 heat and moisture of these pits develop and grow and 

 furnish an abundant supply of food, when other food 

 is not easily available. It was a truly wonderful sight 

 to watch the little creatures engaged in their labors. 

 There was a nest or burrow of these ants under a pile 

 of old rails, which was lying and rusting beside the 

 railway track between La Plata and Ensenada. The 

 entrance was at one side of the pile of rails, and could 

 be seen plainly by stooping down and peering between 

 the rails. The ants in a double stream were constantly 

 pouring into this and emerging. Every ant which went 

 in had a bit of a green leaf, which he had cut from the 

 border of a leaf of alfalfa, which he carried between 

 his mandibles in such a way that its thin edge was 

 forward, and its mass was over the back of the ant. 

 Those that came out had nothing. Along the path 

 which they pursued were a number of soldiers which 

 looked after the workers. The soldier ants are bigger 



