^O Bulletin American Musemn of Natural History. [Vol. XXII, 



and conciliatory as the firstling workers of incipient colonies. And 

 finally, unless the experiments were to be performed in the open 

 country, where they would hardly be practicable, it was necessary to 

 compel the females to reveal as much as possible of the resources of 

 their instincts by preventing their escape from the alien workers. In 

 some cases the nests were large enough to enable the females to keep at 

 a safe distance from the spot on which the workers had settled with 

 their cocoons. 



OBSERVATIONS AND EXPERIMENTS. 



I. Formica difficilis Emery var. consocians Wheeler. 



Owing to the lateness of my arrival in Colebrook during the summer 

 of 1904, I failed to find the males and virgin females of F . consocians 

 and was therefore unable to complete my observations on the habits of 

 this interesting ant. During the past summer I arrived as early as 

 June 27, and at once began a search which resulted in my finding not 

 only the colonies which had been seen in former years but several 

 additional ones in different localities. The species is, however, by no 

 means common. It certainly occurs only in stations occupied by 

 colonies of its temporary host, F. schaufiissi var. incerta Emery. 

 Unlike several members of the nf/a group, consocians is monodomous, 

 that is, its colony is confined to a single nest. The sexual individuals, 

 which were found only in the larger colonies, began to hatch July 3 to 5. 

 The males seemed to make their appearance earlier than the females, 

 and the summer brood of workers did not appear till after the latter 

 had hatched. Most of the colonies contained both sexes, but one was 

 always much more abundant than the other. The opened nests pre- 

 sent a very pretty appearance. The males are deep black, the females 

 rich fulvous yellow with black wings, the workers have a dull orange 

 red head and thorax and an opaque brown and somewhat glaucous 

 gaster. The small size of the females and their parasitic habits would 

 lead one to suppose that they must be produced in greater numbers 

 than the much larger females of F. subsericea, schanfussi, etc., and this 

 is certainly the case. Some of the colonies must have contained as 

 many as 800 females, since fully half that number hatched from part of 

 the cocoons taken from a single colony and kept in one of my artificial 

 nests. As the weather during the past July was extremely warm, the 

 males and females hatched and matured in this and other artificial 

 nests with great rapidity. They became very actively photo tropic 

 just before July 20 and, had they been permitted, would have escaped 



