GEOLOGIC WORK OF ANTS- — BRANNEK. 307 



practically preempted by them. Travelers passing the night in the 

 open have to be constantly on their guard against colonies of ants. 

 Fighting such colonies under the circumstances is simply out of the 

 question. When one finds himself in disagreeable proximity to them, 

 the only thing to be done* is to move at once and leave the ants 

 masters of the situation. 



Bates, speaking of a certain species, says (page 354): 



These Ecitons are seen in the pathways of the forest at all places on the banks of the 

 Amazons, traveling in dense columns of countless thousands. 



On the Rio Tapajos, in the Amazon Valley, he noted the 



quantity of drowned winged ants along the beach; they were all of one species, the 

 terrible formiga de fogo (Myrmica sozvissima), the dead or half-dead bodies of which 

 were heaped up in a line an inch or two in height and breadth, the line continuing 

 without interruption for miles at the edge of the water. The countless thousands had 

 been doubtless cast into the river while flying during a sudden squall the night before, 

 and afterwards cast ashore by the waves. * . . . I was told that this wholesale 

 destruction of ant life takes place annually, and that the same compact heap of dead 

 bodies which I saw only in part extends along the banks of the river for 12 or 15 miles 

 (op. cit., p. 206). 



I have seen similar accumulations of dead female ants on the lower 

 Sao Francisco and the Rio Paraguay, near Corumba, and at two 

 places on tjie shores of estuaries near Aracaju, in the State of Sergipe. 



Bates says the, formiga defogo, or fire ant, was so abundant at one 

 place on the Tapajos that there was scarcely a square inch of ground 

 free from them. (Op. cit., p. 202.) 



The only figures I am able to give in regard to the sizes of ant 

 colonies are the estimates given by Azevedo Sampaio, a Brazilian 

 entomologist who has studied the saubas. He estimates the colonies 

 at from 175,000 to 600,000 individuals. 2 



DESTRUCTI VENESS . 



The destruction wrought by the true ants is confined chiefly, but 

 not entirely, to agricultural products. It is no uncommon thing to 

 find spots where certain ants are so abundant and so destructive that 

 the planters simply leave them alone. Sometimes it happens that 

 after clearing a piece of land, and beginning their planting, the farmers 

 find the ants so destructive that those particular fields are abandoned. 

 In the coffee regions certain ants, popularly known as the saubas, 

 are so destructive that a systematic and unceasing war has to be waged 

 upon them in order to save the coffee trees. But their attacks are 

 not confined to coffee trees by any manner of means. They cut and 

 carry away the leaves of the mandioca plants, orange and lemon trees, 



1 H. W. Bates: The naturalist on the River Amazons, 4th ed., p. 201. London, 1875. 

 » Azevedo Sampaio: Sauva on Manhu-uara, pp. 50, 54. S. Paulo, 1894. 



