COLONY FOUNDING OF ACANTHOMYOPS FULIGINOSUS. 177 



due to the fact that fertile fuliginosus females had entered nests 

 of the former species and been accepted. The queens of the 

 mixtns had then died, or had been killed, either by their own 

 workers or by the fuliginosus females, and the offspring of the 

 latter were reared by the mix t us workers. In the course of time 

 many of the latter had died off, and the few found in the nests 

 were the survivors of the original mix tits colonies. 



" Crawley and I determined to test this hypothesis by experi- 

 ments on captive colonies. In July, 1910, a portion of a nest of 

 fuliginosus was dug up at Darenth Wood, containing a quantity of 

 workers, larvae, males, and winged females, but no queen. The 

 ants and brood were divided into two equal portions and each 

 established in a four-chambered 'Janet' nest. (It may be here 

 mentioned that this ant can not be kept in close confinement, but 

 that if an observation nest be connected by long glass or india- 

 rubber tubes to another plaster nest, or glass bowl, or some other 

 contrivance in which their food is placed, the ants will thus obtain 

 sufficient exercise.) During July all the males died and most of 

 the females, with the exception of about twelve, which were found 

 to be dealated. As some of these latter subsequently laid eggs, 

 from which larvae were reared, it is highly probable that mating 

 had taken place inside the nests. 



' In the beginning of December, 1910, a nest of umbratus with- 

 out a queen was obtained at Weybridge and divided into two equal 

 portions, which were" established in ' Janet ' nests. The first experi- 

 ment was made on December 10, when one of the dealated female 

 fuliginosus was placed in the light chamber of one of the umbratus 

 nests. She immediately entered the most crowded chamber ; one 

 worker saluted her and another dragged her further by a mandible, 

 but eventually she was attacked and killed before evening. On 

 December 13 another dealated female was put into a small plaster 

 nest with some of the workers from the same umbratus nest as in 

 the former experiment. She was slightly attacked, but made no 

 resistance, and endeavored to conciliate her assailants by stroking 

 them with her antennae. When a worker endeavors to bite at the 

 waist of one of these females, she protects it by crossing her hind 

 legs over her back, and when at the neck by pressing her head 

 back close against the thorax. A few more workers were added, 



