356 THE FOUISTDHSTG OF COLONIES BY ATTA SEXDENS. 



structing a large fungus garden about 30 c. c. in size. Sampoio 

 estimated the number of workers to be between 150 and 170, with 

 about 150 larvse and nymphs and 50 eggs. 



In 1898 H. von Ihering contributed some further facts on this 

 subject." He describes accurately the fertile queen ant burying her- 

 self in the ground. A day or two later he found this insect in its 

 nest, but unchanged in condition, and several days afterwards he dis- 

 covered a mound of from 20 to 30 eggs, near which was a flat mass of 

 fungus of from 1 to 2 mm. breadth, without, however, any kohlrabi 

 growing upon it. ^Vlien the fungus bed had reached a diameter of 

 2 cm. the kohlrabi appeared, according to von Ihering, and one could 

 often see the ants feeding on these. From eggs embedded in the 

 fungus garden and lying on its surface larvae had hatched out, but 

 when the mass was removed the fungus wilted and the larvae died. 

 According to A^on Ihering's estimate, two to three months elapse from 

 the start to the appearance of the first workers. He therefore con- 

 cludes that the last portion of the breeding period must be one of some 

 difficulty, seeing that as yet no leaves for the permanent growth of 

 the fungus garden have been brought into the nest. But, as will be 

 shown further on, the cultivation of the garden is provided for. 

 According to my observations, herein recorded, it is by means of 

 ruptured eggs that the proper organic substratum for the garden is 

 supplied, the soil rich in humus also affording nourishment. 



Von Ihering's most important statement is that in some alcoholic 

 material he discovered the fact that each fertile female ant in enter- 

 ing the nest carries in a cavity at the back of the mouth a soft pellet 

 about 0.6 mm. in size, consisting of filaments of the fungus, Rozites 

 gongylophora^ mixed with particles of bleached leaves and various 

 chitin bristles. Unquestionably the possibility of a fungus garden 

 being established by fertile females is rendered evident for the first 

 time by this discovery. 



In 1904 Professor Goeldi, by means of a brood case constructed 

 for the purpose, watched the founding of a colony by a female Atta 

 up to the time of the forming of the pupa ; in fact, to the period of 

 its "ripening" (metamorphosis), but he was disappointed owing to 

 the death of the colony before the mature insects appeared. However, 

 the possibility of a fully isolated female bringing into existence a 

 colony was practically proven by this observation. In a communica- 

 tion on this subject to the Zoological Congress at Bern in 1904 Pro- 

 fessor Goeldi draws the conclusion that on account of the peculiarly 

 granular character of the temporary fungus garden it is probable 

 that broken-up eggs are used as a substratum for the fungus. 



a Die Aulage neuer Kolonien uud Pilzgarten bei AUa sexdens; Zoolog. Anzei- 

 ger, Bd. XXI, pp. 238-245. 



