Brazilian Ants. 



52\ 



Another extraordinary feature in the habits of the tropical ants met 

 with in South America, and which in Europe is likewise only known 

 from the reports of travellers, consists in the wanderings certain 

 species undertake, from time to time, in incredible swarms. The 

 main circumstances of this phenomenon being as yet unknown, I hope 

 that the occurrences I am able to communicate to you, will not 

 prove unacceptable. To a considerable extent the ground is covered 

 with ants, whose motions seem to proceed in all directions, and 

 presenting to the eye nothing but confusion, On observing attentive- 

 ly, however, we find that the whole body advances, although rather 

 slowly, in a certain direction ; all that they meet with in the shape of 

 insects, they drag along with them. How long the expedition lasts 

 I cannot say ; the longest time I had an opportunity of observing it 

 being only five days, on this occasion the march was continued day 

 and night. Should they in their wanderings fall in with a house, they 

 penetrate it by thousands, and the inhabitants must leave it for the 

 time, hence their nocturnal invasions are often as you may suppose 

 very troublesome. They do no further harm, but on the contrary, 

 make up for the inconvenience they occasion, by clearing the house of 

 all sorts of vermin. These immense swarms are continually on 

 their march accompanied by a flock of birds, which destroy a great 

 number of them, and which by their shrill cry, announce the arrival 

 of the insects while they are yet at a distance. As regards the season 

 at which these expeditions happen, I must observe, that all those I 

 find marked in my Journal, take place in the months of June, 

 July, and August. Should this eventually prove to be the only 

 season of their migrations, the circumstance might perhaps throw 

 some light on the season and purpose of this expedition. This 

 season nearly corresponds with our winter, and is, like that, 

 characterized by a considerable diminution in the number of 

 insects. Now, as these afford the principal food of the ant, it is 

 probable, that very numerous societies of ants, not finding in 

 ;he neighbourhood of their dwelling a sufficient stock of nourish- 

 nent for the daily subsistence of the republic, are on that account 

 e orced to emigrate. From this it is seen, why these wanderings 

 lo not take place in Europe where the ants hibernate, and are con- 

 sequently exempted from roving about to seek for their food. 



3 x 



