310 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1911. 



Many writers have described the operations of these ants, but the 

 following, quoted from Dr. Richard Spruce, will give a clear idea of 

 them : * 



One morning soon after sunrise the hut was suddenly filled with large blackish ants, 

 which ran nimbly about and tried their teeth on everything. My chariqui proved too 

 tough for them; but they made short work of a bunch of ripe plantains, and rooted out 

 cockroaches, spiders, and other such like denizens of a forest hut. So long as they 

 were left unmolested they avoided the human inhabitants; but when I attempted to 

 brush them away they fell on me by hundreds and bit and stung fiercely. 



Thomas Belt has a good deal on the swarms of ants in Central 

 America. The following extract is from his "Naturalist in Nica- 

 ragua," page 17: 



One of the smaller species (Eciton predator) used occasionally to visit our house 

 and swarm over the floors and walls, searching every cranny and driving out the cock- 

 roaches and spiders, many of which were caught, pulled, bitten to pieces, and carried 

 off. The individuals of this species were of various sizes, the smallest measuring one 

 and a quarter lines and the largest three lines, or a quarter of an inch. 



I saw many armies of this, or a closely allied species, in the forest. My attention 

 was generally first called to them by the twittering of some small birds, belonging to 

 several different species, that follow the ants in the woods. On approaching, a dense 

 body of the ants, three or four yards wide, and so numerous as to blacken the ground, 

 would be seen moving rapidly in one direction, examining every cranny and under- 

 neath every fallen leaf. On the flanks and in advance of the main body smaller col- 

 umns would be pushed out. These smaller columns would generally first flush the 

 cockroaches, grasshoppers, and spiders. The pursued insects would rapidly make off, 

 but many in their confusion and terror would bound right into the midst of the main 

 body of ants. 



Bates has the following regarding the Ecitons, page 354: 



When the pedestrian falls in with a train of these ants, the first signal given him is 

 a twittering and restless movement of small flocks of plain-colored birds (ant thrushes) 

 in the jungle. If this be disregarded until he advances a few steps farther, he is sure 

 to fall into trouble, and find himself suddenly attacked by numbers of the ferocious 

 little creatures. They swarm up his legs with incredible rapidity, each one driving 

 its pincer-like jaws into his skin, and with the purchase thus obtained, doubling in its 

 tail, and stinging with all its might. There is no course left but to run for it; if he is 

 accompanied by natives, they will be sure to give the alarm, crying, "Taudca! " and 

 scampering at full speed to the other end of the column of ants. The tenacious insects 

 who have secured themselves to his legs then have to be plucked off one by one, a task 

 which is generally not accomplished without pulling them in twain, and leaving heads 

 and jaws sticking in the wounds. 



The errand of the vast ant armies is plunder, as in the case of Eciton legions; but 

 from their moving always amongst dense thickets, their proceedings are not so easy 

 to observe as in that species. Wherever they move, the whole animal world is set in 

 commotion, and every creature tries to get out of their way. But it is especially the 

 various tribes of wingless insects that have cause for fear, such as heavy-bodied spiders, 

 ants of other species, maggots, caterpillars, larvae of cockroaches, etc., all of which live 

 under fallen leaves or in decaying wood. The Ecitons do not mount very high on 

 trees, and therefore the nestlings of birds are not much incommoded by them. 



i Richard Spruce: Notes ol a botanist on the Amazon and Andes, vol. 2, pp. 371-373. London, 190S. 



