82 2 THE POPULAR SCIENCE MONTHLY. 



is therefore spent in running backward and forward upon this semi- 

 diagonal of the square, carrying in food and feeding Class I. Ko 

 black ant is ever seen on the eastern diagonal, and no yellow ant is 

 ever seen on the western ; but each keeps to his own separate station, 

 and here works with a steadfastness and apparent adherence to dis- 

 cipline which are not less remarkable than those exhibited by the sen- 

 tries. The western hole before mentioned seems to be intended only 

 as a ventilating shaft ; it is never used as a gateway. 



Section of the nest reveals, besides passages and galleries, a small 

 chamber, across which is spread, like a spider's web, a network of 

 squares spun by the insects. In each of these squares, supported by 

 the web, sits one of the honey-secreting ants (II). Here the honey- 

 makers live in perpetual confinement, and receive a constant supply of 

 flowers, pollen, etc., which is continually being brought them by I, 

 and which, by a process of digestion and secretion, they convert into 

 honey. It is particularly noteworthy that in this truly wonderful 

 exhibition of social cooperation the black and yellow workers appear 

 to belong to two distinct genera ; for hitherto this is the only case 

 known of two distinct species of animals cooperating for a common 

 end. 



EciToxs. We have lastly to consider the most astonishing insects, 

 if not the most astonishing animals, in the world. These are the so- 

 called " foraging," or, as they might more appropriately be called, the 

 military ants of the Amazon. They belong to several species of the 

 same genus, and have been carefully watched by Bates, Belt, and other 

 naturalists. The following facts must therefore be regarded as fully 

 established : 



Eciton legionis moves in enormous armies, and everything that 

 these insects do is done with the most perfect instinct of military or- 

 ganization. The army marches in the form of a rather broad and 

 regular column, hundreds of yards in length. The object of the 

 march is to capture and plunder other insects, etc., for food, and, as 

 the well-organized host advances, its devastating legions set all other 

 terrestrial life at defiance. From the main column there are sent out 

 smaller lateral columns, the composing individuals of which play the 

 part of scouts, branching off in various directions, and searching about 

 with the utmost activity for insects, grubs, etc., over every log and 

 under every fallen leaf. If prey is found in sufficiently small quanti- 

 ties for them to manage alone, it is immediately seized and carried to 

 the main column , but, if the amount is too large for the scouts them- 

 selves to deal with, messengers are sent back to the main column, 

 whence there is immediately dispatched a detachment large enough to 

 cope with the requirements. Insects or other prey which, when killed, 

 are too large for single ants to carry, are .torn in pieces, and the pieces 

 conveyed back to the main army by different individuals. Many 

 insects in trying to escape run up bushes and shrubs, where they are 



