1906.] Wheeler, Founding of Colonies by Queen Ants. 89 



soon released her. She rested near the workers and spent much of her time 

 cleaning herself. By 6 p.m. there were 3 dead workers in the nest, showing 

 that she must have resented some of the indignities to which she had been 

 subjectsed during the day, for the workers seized her from time to time and 

 dragged her about the nest by a leg or an antenna. When released she escaped 

 to a comer of the chamber but soon returned to the workers and brood as if 

 seeking adoption. Often the workers came up and felt of her and then passed 

 on without molesting her. Aug. 30, 7 a.m., during the night another worker 

 had been killed. The female was still in excellent condition. She was pulled 

 about by a large worker but offered no resistance. Others repeatedly pulled 

 her away from the brood, but as soon as she was released she returned to the 

 workers' comer. Aug. 31,7 a.m., she was uninjured and hung about the work- 

 ers' comer all day. By 6 p.m. she had lost her left antennal funiculus and was 

 so weak that there was no hope of her survival. She had lived 5 days in a nest 

 with 9 to 13 unusually large schaufussi workers. 



In these two experiments the behavior of the Polyergus female 

 was much like that of F. consocians in inceria nests and strongly sug- 

 gested adoption as the method of colony formation. I planned a 

 number of other experiments in the hope of gaining a clearer insight 

 into the peculiar behavior of the Polyergus females, but was prevented 

 from carrying them out by the rapid dying off of these insects in 

 their own nest. Hence this portion of my work, like that on F. 

 subintegra and aserva, will have to be continued another summer 

 under more favorable circumstances. 



General Considerations. 



The foregoing simple experiments, which consisted in compelling 

 female ants, mature but mostly unfertilized, and artificially dealated, 

 to consort with small colonies of alien workers, all go to con- 

 firm, what has long been known, that worker ants of one species 

 are hostile to females of another species. It is clear, however, 

 that this hostility is not always manifested with uniform intensity. 

 Towards the females of the Formica rufa and exsecta groups, it is often 

 feeble or even evanscent, so that in these cases mixed colonies can be 

 produced consisting of adult individuals of both species. Under 

 normal conditions such colonies are necessarily temporary, since they 

 are destined, after the death of the original workers, to resolve them- 

 selves into pure colonies of the species to which the fertile queen be- 

 longs. Towards the females of F. sanguinca and Polyergus the hostility 

 of alien workers is so pronounced and persistent that mixed colonies 

 cannot be produced as in the former case. The females are obliged 

 to exterminate the old workers and to take possession of the brood 



