POWER OF RECOGNITION AMONG ANTS. 239 



Nest B i. --On April i, 1904, over six months after their 

 segregation, there were in the Bi nest about sixty Stenammas. I 

 then introduced to their nest two Lasius, their former comrades, 

 taken from nest B2. No fear was evinced by the Lasius, and 

 no aversion by the Stenammas. Residents and visitors perfectly 

 affiliated, and the two Lasius remained safely in the Bi nest 

 four full days. I then, on April 5, removed the two Lasius, and 

 put them into a nest of Stenamma fiihnun where there were two 

 queens and sixteen workers, all hatched in August, 1902, and 

 therefore a year older than were the ants in nest Bi. They 

 were from the same C colony, but had never associated with 

 Lasius. In this nest the Lasius tried to flee or to hide, behav- 

 ing as do ants when in a nest of recognized enemies. At first 

 they eluded the Stenammas, but when I again examined the nest, 

 on the evening of the same day, both Lasius had been killed and 

 put on the rubbish-heap. 



It appears that these very strong-smelling ants, the Lasius, 

 had not so changed their odor during six months that the Bi 

 Stenammas did not recognize it. But on June 1 1, 1904, I took 

 from the wild nest of the F colony two Lasius workers, of un- 

 known age, and introduced them into the Bi nest of Stenammas. 

 They were soon killed, and two like them were also killed when 

 introduced on the ensuing day. 



On August ii, 1904, I introduced a newly hatched Lasius 

 from the R colony, and it was at once killed. 



On June 1 1, 1904, I sought in the old wild nest of the Lasius 

 F colony for a remainder of its population, and secured a few 

 workers and four larvae. On August 4, three cocoons and one 

 naked pupa had appeared from these larvse, and from these 

 cocoons the first worker hatched on August 18. It was im- 

 mediately put into the Bi nest, where it appeared as a yellow 

 pigmy among brown giants. It was much patted with the 

 antennae, was licked, and was cared for among the eggs, larvae 

 and pupae over which the Stenammas were strenuously engaged. 

 The Stcnai/unas recognized an odor from which tJicy had been 

 eleven months separated. 



The Stenammas of nest Bi met no Cremastogaster from Sep- 

 tember 24, 1903, until July 7, 1903, when I introduced into their 



