234 A. M. FIELDE. 



periment eleven months old, a callow of the same colony, just 

 seven days old. The callow received careful examination from 

 the older ants, and was then amicably entertained by them. 

 They doubtless recognized in the callow their own early odor. 



Experiment F.--On July 6, 1904, after the queen and the 

 fourteen workers mentioned in experiment D were all serenely 

 grouped in the nest there described, I introduced two workers 1 of 

 the N colony, hatched between August 14 and September 3, 1903, 

 and therefore about ten months old, while the resident ants were 

 not over seventy-three days old. The two visitors had affiliated 

 previously with the N queen, and had been approved by her. 

 They were probably the issue of her eggs of the previous year. 

 They were, however, seven or eight months older than the resident 

 workers, and, although they were larger than any worker resi- 

 dent, they were persistently attacked and dragged, sometimes by 

 more than one resident at a time. The visitor-ants did not retal- 

 iate. One of them tried to placate her young sisters by offers of 

 regurgitated food, and after a half hour there were signs of dimi- 

 nution in the strength of the attacks. I- then removed the visi- 

 tor-ants. There are all degrees in the hostility shown by ants 

 to one another, as well as many variations in the degree of close- 

 ness in their affiliations. 



In this experiment, the older ants had met no younger ones 

 during their lives, and the younger ones had never before en- 

 countered sisters older than themselves. 



RECOGNITION OF ODORS OF OTHER SPECIES. 

 TJic A Scries. 



Evidence of ability to recognize odors that have not been 

 encountered during many months has been taken from ants of 

 diverse species and of a recorded life history. In August, 1903, 

 I formed a mixed colony of workers of Camponotus pennsylvani- 

 ciis, Formica subsericea and Stcnannna fnlvnm, all of whom 

 hatched in my artificial nests between August 14 and Septem- 

 ber 3. Every ant within a few hours after its hatching was 



1 My method, which is also Forel's, of marking ants so as to readily distinguish 

 them from others of their species, is described in a foot-note of " Notes on an Ant," 

 already referred to. Ants were marked whenever an experiment required it. 



