42 Bulletin American Museum of Natural History. [Vol. XXII, 



the number of workers at 150 to 170, that of the larvae and pupae at 

 about 150, and the eggs at 50. 



The much more important observations of von Ihering, including 

 his brilliant discovery of the method of transfer of the fungus culture 

 from the maternal to the daughter colony, deserve fuller consideration. 

 According to this observer there are repeated nuptial flights of the 

 Brazilian Atta sexdens from the end of October to the middle of De- 

 cember. His account of these flights shows that they are essentially 

 like those of other ants, so that his supposition that the female may be 

 fertilized in the parental nest is without foundation. His account of 

 the founding of the colony is so interesting that I cannot refrain from 

 quoting it. 



The fertilized female "rids herself of her easily detached wings by 

 quick motions of her legs and then begins to dig her burrow in some 

 spot more or less free from vegetation. This canal is nearly or quite 

 vertical and measures about 12-15 mm. in diameter. It is so narrow 

 that the 'Iga' cannot turn round in it, but is compelled to walk back- 

 wards whenever she returns to the surface. She bites off lumps of 

 earth with her powerful jaws, makes them into a pellet by means of 

 loose threads of saliva, brings them up and deposits them a short dis- 

 tance from the entrance to the burrow. The earth thus brought up 

 forms a circular wall, thickened in front and interrupted behind, about 

 4-5 cm. broad in front and at that point 3 cm. from the entrance. The 

 burrow varies in length according to circumstances from 20-30 cm. 

 and ends in a small laterally placed chamber about 6 cm. long and 

 somewhat less in height. As soon as the chamber is completed, the 

 ant closes the upper portion of the burrow to a distance of 8-10 cm. 

 from the entrance with pellets of earth and this closure becomes more 

 and more compact in the course of weeks, probably through the action 

 of the rain. 



" If the nest be opened in one or two days, the female will be found 

 in the empty chamber unchanged, only more lethargic, as if exhausted. 

 A few days later one finds near the ant a little packet of 20-30 eggs 

 undergoing segmentation. Beside them lies a flat heap of loose white 

 substance, only 1-2 mm. in diameter. This is the earliest rudiment 

 of the fungus garden. Microscopical examination shows that it con- 

 sists of compact masses of the well-known fungus-hyphae, but no traces 

 of "kohlrabi " corpuscles. As time goes on the fungus garden grows 

 rapidly and becomes more voluminous till it reaches a diameter of 

 about 2 cm. It seems to consist of closely aggregated spherules about 

 I mm. in diameter. As soon as it has attained this size the trans- 



