THE PROGRESSIVE ODOR OF ANTS. 13 



workers of Stenamma fulvum piccuin had been inmates of one of 

 my mixed nests, with Camponotus pennsylvanicus and Formica 

 subscricca, all hatched between August 14 and September 3, 

 1903. The Stcnammcts had been removed from the mixed nest, 

 and kept in segregation since June 23, 1904, and had never met 

 a queen. On August 13, 1905, I introduced into this nest a 

 young, winged queen of the same variety as these workers, on the 

 twenty-fourth day after I had isolated her to ensure her freedom 

 from incurred odor. The queen fled from the group of workers 

 and constantly tried to escape. She was attacked whenever I 

 forced her into the group of workers, and was caught and killed 

 by them on the ninth day of her sojourn. A dealated queen intro- 

 duced later, from the wild colony to which these workers origi- 

 nally belonged, was also killed by them. 



Since ants possess so discriminating a sense of smell, and are 

 so exacting concerning an adherence to the criterion established 

 for their nest, and since even those ants who have had an ex- 

 tended experience in ant-odors, and who have been queenless for 

 two years, refuse to affiliate with a queen of an alien odor though 

 of their own variety, we may hardly expect that they will volun- 

 tarily associate with queens of another species. During the sum- 

 mer of 1905 I introduced queens of other species into segregated, 

 queenless groups of adult Stenamma fulvum^ of Formica ncoga- 

 gatcs and of Formica Schaufussi, that had had their sense of smell 

 highly educated by long association with workers of two or three 

 different species of ants, but in every case the introduced queen 

 was killed within a few days, in spite of her constant efforts to 

 keep aloof from the workers. 



In no species of ant have I found workers that would tolerate 

 the presence of any queen of unfamiliar odor, nor any queen that 

 would willingly remain among workers of unfamiliar odor. 

 Although all species of ants have not been thus tested we may 

 well assume that what is shown to be a fundamental trait in a few 

 species will manifest itself in all species of the tribe. 



