8o Bulletin American Museum of Natural History. [Vol. XXII, 



Another worker had been killed. The remaining 2 were wandering about aim- 

 lessly and not endeavoring to recover their cocoons. One of them had lost an 

 antenna. At 1.30 p.m. they tried to associate themselves with the rubiciinda 

 and suhsericea females. The latter were a link between the two inimical fac- 

 tions represented by the workers and ruhicunda. July 19, 7.30 a. m. the colony 

 was in statu quo except that one of the subsericea females was dying. July 20, 

 7.30 A.M. During the night the ruhicunda had killed one of the workers and 

 injured another. She was now in full possession of the brood and two surviving 

 subsericea females. July 21 the experiment was discontinued. 



Experiment j/. July 14, 2. p.m. A vigorous and active rubicunda female 

 was placed in a nest with 9 subsericea workers and about 150 worker cocoons. 

 By 2.17 P.M. she had killed 6 workers and was rushing wildly about the nest, 

 apparently more in fear than in anger. Two of the three remaining workers 

 were callows. By 5.20 p.m. she had carried nearly all of the cocoons to a 

 corner of the nest and was standing guard over them with open mandibles. 

 At 6 P.M. one of the callows associated herself with the female. July 15, 

 7 A.M. the other callow had joined the female, who had transferred all the 

 cocoons to another corner of the nest. The single mature worker was lurking 

 in the diagonally opposite corner. The dead subsericea which were scattered 

 about the nest yesterday had all been collected (by the female?) and placed 

 in a pile near the cocoons. Whenever the nest was uncovered the female en- 

 deavored to conceal the brood. July 16, 8 a.m., 3 callows had hatched in the 

 night. The mature worker was with the brood, but ran away and hid when 

 the nest was uncovered. The female was very alert and showed great solic- 

 itude for the brood. At 2.20 p.m. the single adult worker kept away from 

 the brood and tried to escape from the nest by gnawing at the towelling. July 

 17, 7.30 A.M., this worker had joined the callows and all the ants were living 

 peacefully together. Later in the morning the total number of workers had 

 risen to 12. At noon the single mature worker deserted the brood and went to 

 stay in the light chamber, the entrance to which had been closed on the previous 

 day. July 18, 8 a.m., there were 27 subsericea workers altogether. The single 

 mature worker had again joined the colony during the night and mingled with 

 the callows. Henceforth she became a permanent member of the colony. 

 The number of workers increased to 36 by noon. July 19, 7.30 a.m., there 

 were 51 subsericea. The female was very timid when the nest was uncovered. 

 Although she seemed to be much interested in the callows she was not seen 

 to care for the cocoons after the callows had begun to aid one another in hatch- 

 ing. The number of subsericea increased as follows: July 20 there were about 

 60; July 21 about 80; July 22 about 90; July 23 more than 100. At 12 M. on 

 the date last mentioned the colony was given 150 worker cocoons of F. rufa 

 integra. They at once seized them and began to carry them to the pile of un- 

 hatched cocoons of their own species. July 24, 8 a. m., there were about 125 

 subsericea in the nest. They were carefully hoarding the integra cocoons mingled 

 with a few remaining cocoons of their own species. July 25, 7.30 a.m., the 

 subsericea took a few of the integra pupas out of their cocoons, killed them and 

 threw them on the refuse heap. Two callow integra were walking about the 

 nest. July 26 both of these callows had been killed. The nest was transported 

 to New York and not examined till August 6, when nearly all the integra had 



