ANTS AND THEIR SLAVES. 899 



le motif qui pousse les sanguinea a se faire presque 

 toujours des esclaves.' 'Peut-etre,' he adds, Me senti- 

 ment de leur force, et le desir de travailler moins, pour 

 faire plus a leur aise la chasse aux Lasiua fiavua et 

 L. niqevy est-il le mobile qui les pousse a cet acte. 

 Celui-ci leur serait peu k peu devenu plus ou moins 

 instinctif puisqu'il etait avantageux a la conservation 

 de leur esp6ce.' This suggestion seems very probable, 

 and may be partially correct; it is not, however, I 

 think, a complete explanation. I have had under 

 observation several nests of F. sanguinea. One of 

 them I owe to the kindness of M. Forel himself, who 

 sent it to me in June 1882. There was no queen, 

 and, though the nest was very healthy, of course the 

 numbers gradually diminished. At the beginning of 

 January 1886 the last slave died, and there then re- 

 mained only about fifty F. sanguinea. Under these 

 circumstances the F. sanguinea began to die off 

 rapidly ; by the middle of the year only six re- 

 mained alive, and these, no doubt, would not have 

 survived long. On July 1, 1 got some pupa3 of F. 

 fusca and placed them outside the nest. The sangui- 

 neus soon discovered them, carried tbem into the nest, 

 ftnd from that day until December 1887, more than 

 six months, there was only one other death. [Two 

 of the F. sanguinea are still (August 1888) alive.] 

 Although then it may be true, as to which I express no 

 opinion, that there are nests of F. sanguinea without 

 slaves, still this observation seems to indicate that the 

 slaves perform some important function in the economy 

 of the nest. It still remains to be determined in what 

 exactly this function consists. 



Ant-Guests. 

 Dr. "Wasmann has recently published ' an interests 

 ing memoir on certain of these ' Ant-guests.' His 



■ Deutsche Entom. Zeitsohrift, 1886, p. 49. 



