Architecture in the Animal Kingdom. 105 



sanguinea colonies here (No. 112 of stat. map) is 

 built in a lofty and sturdy oak, in the mould and the 

 clefts of a holl6w in the tree, almost a yard above the 

 ground. These observations show that the sanguine 

 ants are able to choose the most peculiar places for 

 their nest and to adapt its construction to any local 

 circumstances. This is confirmed by the following 

 observation. In the immediate neighborhood of Exa- 

 ten the earth-nests prevail, while two kilometers further 

 or near the village of Grathem, the greater number of 

 nests are built in rotten fir-stumps, because in that 

 region the ground is more turfy and thus renders the 

 construction of earth-works rather laborious. 



Not less variable than the style is the number of 

 nests constituting a colony of F. sanguinea. Among 

 the above mentioned 410 colonies which are known 

 to me in this region, there are but a few that have only 

 one nest. These are mostly weak tribes which, on 

 account of the scarcity of members, feel no need of 

 other nests. In some cases, however, even a very 

 strong colony has only a single nest built in a specially 

 convenient place, generally at the foot of a fir 

 (e. g., col. 208 and 216). In such cases the concen- 

 tration of the building is of greater advantage than 

 its division into a number of different nests. 

 However, by far the majority of the sanguinea colo- 

 nies have several nests, averaging from two to eight, 

 either close together or farther off from another, some- 

 times inhabited simultaneously, sometimes by turns. 

 The distance between the nests of one colony is mostly 

 only from ^ to 4 m., but sometimes from 10 to 20 m. 

 or more. The latter is particularly the case with their 



