GEOLOGIC WORK OF ANTS—BRANNER. 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 sevissima), 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.! . . . Iwas 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 the shores of estuaries near Aracaju, in the State of Sergipe. 
Bates says the formiga de fogo, 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 satibas. He estimates the colonies 
at from 175,000 to 600,000 individuals.? 
DESTRUCTIVENESS. 
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 saibas, 
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. Theycut and 
carry away the leaves of the mandioca plants, orange and lemon trees, 
1H. W. Bates: The naturalist on the River Amazons, 4th ed., p. 201. London, 1875. 
2 Azevedo Sampaio: Sauva ou Manhu-uara, pp. 50, 54. S. Paulo, 1894. 
