104 Chapter HI. 



tation of the hereditary instinctive activities. As 

 these ants, in the parlance of modern animal psychol- 

 ogy, possess a high degree of "individual intelligence," 

 because under the influence of their sense-perceptions 

 and sense-experiences they are able to adapt their 

 innate, instinctive dispositions and aptitudes to any kind 

 of circumstances, so they manifest great adaptibility in 

 the building of their nests. I have drawn up statistics 

 of the sanguinea colonies in the neighborhood of Exa- 

 ten, which show that to my knowledge there are in 

 this region about 2,000 nests of this ant species, 

 embracing 410 colonies. The architectural style of the 

 nests varies greatly. By far the majority of them 

 are underground, built either below the bare surface 

 or under a shrub of heather, beneath a loose clod, 

 under a stone or at the foot of a tree. In connection 

 with this underground earth-nest there is generally 

 on the surface a greater or smaller heap of dry leaves 

 collected from the heather shrubs. This heap, together 

 with the earth carried out of the interior galleries and 

 the twigs of the shrubs supporting the whole construc- 

 tion, forms a sort of protective dome. With large nests 

 this hill sometimes has a circumference of several 

 meters and a height of several decimeters (e. g., in 

 colonies Nos. 208, 216, 118); but often it is rather 

 insignificant and sometimes it is altogether wanting. 

 Besides these simple or mixed earth-nests, F. san- 

 guinea builds also in rotten stumps of fir-trees or oaks, 

 now under the loose bark, now in the wood, now in the 

 roots. Sometimes the old stump is surrounded by 

 earth-galleries, and sometimes the whole nest is con- 

 fined to the stump itself. The nest of one of our 



