THE FOUNDING OF COLONIES BY ATTA SEXDENS. 357 



If we now group the results obtained from these previously men- 

 tioned investigations, w^e secure some such conception of what has 

 already been done as that embodied in an article by Professor Forel, 

 recently published in this journal.'* It should be stated, however: 

 (1) So far no investigator has succeeded in following the formation 

 of an Atta colony up to the time of appearance of the young workers, 

 much less the establishment of a permanent fungus garden. (2) The 

 manuring of the fungus is thought by two authors to be accomplished 

 by means of ruptured eggs; but this is not yet established beyond 

 doubt. (3) Investigation has not yet revealed the source and method 

 of feeding the larvae. 



On January 20 of the present year (1905), Professor Goeldi began 

 a new series of observations of a number of females of Atta sexdens 

 which had embedded themselves in earth inside of a breeding box of 

 his construction. Although at the outset I was associated with him 

 in these observations for the specific purpose of investigating the 

 fungus, I was later on intrusted with the entire investigation, Pro- 

 fessor Goeldi being absorbed in other work. During my studies and 

 observations, continued in an unbroken series through February, 

 March, and April, I repeatedly received aid and encouragement from 

 Professor. Goeldi, especially in matters of information relating to 

 literature bearing on this subject. In recognition of this I desire to 

 here express to him my heartiest thanks. 



The series of observations, begun January 20 with about 12 fertile 

 females, were further enlarged by two other series containing num- 

 berless individuals, secured from flights occurring on February 23 

 and March 12, a circumstance that rendered possible investigations 

 by diverse methods of cultivation. On this point it is sufficient to 

 here state that besides a large number of cultures in the Goeldi breed- 

 ing case filled with earth, others were placed in crystallizing dishes 

 (to afford observation from above) and in small plaster boxes having 

 glass sides at front and back (to afford observation from the side) ; 

 and in addition to these a number of nests in the open ground, marked 

 at the time the fertile female embedded herself, were opened at the 

 ])roper time as indicated by a control experiment. These observa- 

 tions were so far crowned with success as to result not only in follow- 

 ing, without a break, several cases of the founding of new colonies 

 from the beginning to the time of appearance of the workers, but also 

 in some instances in observing the commencement of leaf-cutting 

 operations and the constructions of a permanent fungus garden. 

 Repeated and careful observations of the Atta female and her 

 descendants yielded also a niunber of interesting facts which I shall 

 here merely enumerate, reserving for a more elaborately illustrated 



a Biolog. Ceutralblatt, Bd. XXY. p. 170 ft". 



