1901.] NATURAL SCIENCES OF PHILADELPHIA. 535 



Queens and workers will usually live peaceably with auy ant 

 that they have reared from the pupa, and they may be caused to 

 rear successive broods of unlike lineage, or to rear at one time a 

 brood from eggs, larvte or pupse of div^erse stock. But both queens 

 and workers appear to be less at ease and to filiate less closely 

 with such associates than with those of their own line, unless they 

 greatly outnumber the introduced members of their group. If 

 pupse of alien stock are given to them in large numbers, shortly 

 before the pupte become callows, many of the callows are immedi- 

 ately killed. 1 segregated three groups, each consisting of a colony 

 C queen and seven adult workers, and gave to each group eight 

 pupse from colony E. In two of these groujDS the pupte all became 

 callows within four days and all were killed. In the third group 

 the pupse were younger, none became active before the seventh day 

 after being introduced, and five were permitted to live. These 

 five callows had doubtless, during their longer residence in the 

 group fostering them, been overlaid with the odor of the C colony, 

 and therefore when they became active they bore an odor inofien- 

 sive to their adult companions. They were doubtless smeared 

 with the odor of their hosts. 



I have repeatedly seen a queen, with numerous workers of alien 

 stock, flee from the group of ants that I had induced her to rear 

 in her own nest. She had been unable to lick so many pupse into 

 her own likeness. 



Ants remember, or are for some time positively chemotropic to, 

 the odor to which they were earliest accustomed. An isolated queen 

 of the D colony first reared four workers from larvse of the C 

 colony, and later on this mixed group reared three callows from 

 pupse of the E colony. When these callows were fifteen days old 

 I removed them to the E colony, where they were happily domes- 

 ticated five days. I then sequestered them in a Petri cell, and 

 found that they instantly affiliated with either the D colony queen 

 or the C colony workers that had earliest fostered them. They also 

 affiliated with C colony adults deprived of the smell-sense. 



Two queens of the C colony separately reared eight callows from 

 pupse of the E colony. When the callows were from eight to fifteen 

 days old, I put the two queens into one Petri cell and the eight 

 callows into another, and kept the C and E ants thus apart for 

 thirty days. I then reunited the queens and the young ants and 

 thev again filiated, with no sign of distrust or aversicm. 



