Architecture in the Animal Kingdom. Ill 



hill in the forest, however, was in ruins, a sig^ that it 

 had been completely abandoned by its builders. 



Neither experience, nor instruction, nor ''profound 

 thought" could have taught the ants, that tar-paper 

 possesses in a high degree the qualities which allowed 

 them to dispense with an ant-hill ; for it was a material 

 which ants are not wont to meet with. It is not, there- 

 fore, "intelligence,'^ but the instinct of ants that rightly 

 accounts for a change of nests seemingly so wise. The 

 first ants that happened to find the paper were de- 

 lighted with the place; their senses were impressed 

 with its comfort and security. This led them to bring 

 over some of their nest-mates, and since these also 

 were pleased, the whole colony finally emigrated and 

 settled at the new place. The sensitive powers of 

 cognition and appetite also explain very easily, why 

 the ants did not raise a hill above the tar-paper. Under 

 the artificial roof they felt safe and warm enough 

 without a superstructure, therefore they saw no need 

 of any additional construction. Other ants, too, often 

 omit to build above ground, when they meet a 

 stone, that furnishes sufficient warmth and protection 

 for the underground parts of the nest. Even of F. 

 rufa, which is the most typical "hill-ant," I found a 

 series of nests under stones, near Goebelsmuehl, 

 (Luxemburg) in July, 1904. 



As ants, and in particular the sanguine slave- 

 makers, are able to adapt their skill in building nests 

 to the most varied localities and conditions of season, 

 so the same instinct manifests great plasticity with 

 regard to sudden emergencies, e. g., against the attacks 

 of their various enemies. A weak colony of F. san- 



