April, '09] JOURNAL OF ECONOMIC ENTOMOLOGY 175 



nine immature stages in all. Plate 5 shows a colony consisting of 

 one queen, about 100 workers and about 20 eggs, with no larvffi, 

 pupge or males present. 



In size the colonies may vary from a dozen to many thousands of 

 individuals and the number of queens present in a colony may vary 

 from one to many hundreds. Though the Argentine ant is particu- 

 larly aggressive and a hard fighter when coming in contact with most 

 other species of ants, there is no apparent antagonism between sep- 

 arate colonies of its own kind. In fact, in heavily infested areas the 

 workers and queens are so intermingled that the individuality of 

 colonies is entirely lost sight of and all colonies appear to become 

 part and parcel of one enormous "community." In this respect the 

 species may be said to have a more perfect social organization than 

 even the honeybees, colonies of which are very distinct and the indi- 

 viduals of which repel with alacrity any visitor from another colony. 



Methods of Study 



When the study of this ant was undertaken two requisites pre- 

 sented themselves, a form of artificial formicary in which continu- 

 ous observations could be made and individuals kept track of from 

 the time of egg deposition until the adult stage was reached, and some 

 method by which all individuals of a colony could be confined to 

 their OAvn formicary. 



Artificial formicaries, or cages, of various types were made and 

 tried. Among them were cages consisting of two glass cylinders 

 placed one within the other, the intervening space filled with soil, 

 the Janet cage, molded of plaster of Paris and having several com- 

 partments, and wooden and glass cages constructed in the form of 

 cubes, from which the ants could not escape. None of these met the 

 requirements. In the cylindrical cages crumbling earth often de- 

 stroyed the galleries and it was impossible to so regulate ' the space 

 between cylinders that the ants could not construct invisible galleries 

 into which eggs and larva? were carried. 



The Janet cages proved successful only in the case of very large 

 colonies, but in these the multiplicity of individuals made accurate 

 observations impossible. It may be remarked that this type of cage 

 is excellent for studying the community life as a whole and for mak- 

 ing experiments with poisons or with parasitic fungi or bacteria. 



Cages totally enclosed were not successful for the reason that the 

 ants, when deprived of the privilege of leaving their nest, failed to 

 act in a normal manner. 



The cage finally adopted was, with modifications, the one described 



