ADOPTION OF QUEENS BY ALIEN SPECIES. 283 



and myself (igoic). Schmitt found near Beatty, Pa., a small mixed colony of A. 

 tennesseensis and A. picea, a variety of fulva, and one of the commonest ants in 

 the northern states. He was impressed with the fact that the nest of this colony 

 was under a stone, because tennesseensis normally nests only in rotting wood. 

 During the summer of 1902 I found near Rockford, 111., two mixed colonies like that 

 observed by Schmitt, except that the variety picea was represented by the 

 variety rudis. Both colonies were of small size and situated under stones. In one 

 of them a tennesseensis queen was unearthed. There can be little doubt, therefore, 

 that the glabrous queens seek out small nests of some variety of fulva and start 

 their colonies in them just as consocians does in the nest of incerta. This habit 

 is also indicated by the sporadic distribution of tennesseensis and its occurrence 

 only in localities where some form of fulva is abundant." 



The reasons for performing adoption experiments with queens 

 of the other species will be given as I take up those experiments. 



METHOD. 



The method used in these experiments consisted in placing 

 artificially dealated queens of the supposedly parasitic species 

 in a nest with a few workers and brood of the supposed host 

 species and observing their behavior under these conditions. 

 This is the same method used by Wheeler in the experiments 

 recorded in the paper mentioned above, and possible objections 

 to it are answered by stating that an artificially dealated queen 

 behaves in the same manner as a fertilized queen that has dea- 

 lated herself, and that if one is to conduct such experiments on a 

 large scale it is necessary to use artificial nests and to prevent the 

 escape of the introduced queen. For most of the experiments 

 I used large Petri dishes 4 1/2 and 6 in. in diameter into which I 

 dumped the ants with their brood and some earth from the nest. 

 For some of the experiments, however, I used nests of the Fielde 

 pattern, and in that case I always introduced the queen into the 

 light chamber and allowed her to find her own way into the dark 

 chamber where most of the ants stayed, thus imitating natural 

 conditions a little more closely. When I used Fielde nests, 

 one chamber was kept covered with a piece of orange-colored 

 glass. A few of the experiments with each species I watched 

 very closely, especially when the queen was first introduced, 

 sometimes watching a nest almost constantly for several hours, 

 but as I had a large number of experiments going at the same 

 time, sometimes more than fifty, I had to be content with examin- 

 ing most of them hastily several times a day and depending 



