152 Chapter VIII. 



Claviger, etc., and their hosts, I have met with instances 

 of this second form of learning in the manner in which 

 these ants become acquainted with their new guests. 

 At first they are provoked to make an hostile attack 

 upon the beetle on account of its strange shape and un- 

 wonted odor. But on chancing to touch its yellow hair- 

 tufts with their mouths, they make the agreeable ex- 

 perience of licking something highly aromatic, and 

 change their hostile attitude into a friendly disposition 

 often within a few minutes. In future they do not 

 experience any hostile reaction through the odor and 

 shape of the new guest, but tend and feed it, so that 

 other individuals of the same species of beetle, which 

 are subsequently put into the nest, are immediately ad- 

 mitted into the community, even though the odor of a 

 strange species of ant may still adhere to them. We 

 can explain this phenomenon only by saying, that the 

 soothing experience made with the first beetle aroused a 

 new association of representations in the sensitive pow- 

 ers of the ants, in virtue of which the second beetle 

 made at once a very different impression on them, from 

 that which was caused by its predecessor at their first 

 encounter. 



Another observation, that I made with this nest of 

 Formica sanguine a, belongs undoubtedly to the same 

 class of biological phenomena. A Dinar da dentata had 

 been for some time a tolerated, if not a welcome guest 

 of the community. But on account of experiences with 

 a closely allied, but little larger species, the Dinarda 

 Maerkeli* toleration turned into a hostile attitude. 



*) See "Vergleichende Studien" (1st edition), p. 38; "Die psychi- 

 schen Faehigkeiten der Ameisen," p. 84. 



