106 Chapter III. 



summer and winter residences, or rather with the 

 abodes for winter and for spring', for, many but by 

 no means all sanguinea colonies of this country have 

 special winter-quarters established in thickets under 

 the roots of trees or stumps and affording deep and 

 warm recesses for the cold season. The spring resi- 

 dence, however, which again often consists of several 

 single nests, is generally built near the edge of the 

 thicket. Here, on the first warm days of March and 

 April, the ants can always be observed changing their 

 quarters and moving over with the whole family to 

 the spring residence. In September or at least in the 

 beginning of October they change again, moving in 

 the opposite direction. 



If it should become very hot and dry in summer, 

 the colonies move to their winter quarters during the 

 dog-days, thus converting the winter nest into a mid- 

 summer nest.^ When at the end of August, 1898, I 

 had returned after several weeks of absence, I found 

 that during the exceptionally hot days of August most 

 of the sanguinea colonies of this region had aban- 

 doned their spring nest. What had become of them? 

 As I was well acquainted with the winter nests of many 

 colonies by the means of the statistical map I had 

 drawn up in the preceding years, it occurred to me to 

 look there in search of them. The result was rather 

 striking: all of the emigrated colonies possessing 

 winter quarters of their own, had already occupied 

 them ! This was such a regular occurrence, that, when 



*) The country about Exaten consists in its uppermost layer of 

 light sand, which at once loses all its moisture in places exposed for 

 some time to the scorching rays of the sun. This condition of the soil 

 is surely essential in explaining the facts just mentioned. 



