40 



bring up her brood. In only one case did he find an incerta 

 female present. In course of time the nest assumes the form 

 of a consocians nest, and eventually becomes entirety such. 



His experiments with these two species demonstrated several 

 surprising facts : 



1. A consocians female that has been living with incerta 

 workers is readily accepted by strange incerta workers. 



2. If a consocians female has been living with her own species, 

 she is not accepted unless very young. 



3. A consocians female that has been living with incerta 

 workers is violently attacked by a colony of her own species. 



4. An incerta colony is far less hospitable to strange incerta 

 females than to consocians females that have been living with 

 strange incerta workers. 



Other instances that Wheeler found in North America are 

 F. microgyna (he found three mixed colonies of F. microgyna, 

 V. rasilis, and F . fusca, v. argentata) and F. dakotensis which he 

 found in association with F. incerta in Colorado. Muckermann 

 found mixed colonies of F. dakotensis, v. wasmanni, and F. 

 subsericea. 



Wheeler suggested that a similar condition would be found 

 to obtain with F. rufa and exsecta and F. fusca in Europe. This 

 would, of course, explain the mixed colonies above mentioned 

 found by Forel. The female of F. rufa is, however, much 

 larger in proportion to its workers than those of the American 

 ants just mentioned, but though fresh colonies are most often 

 formed by branches from the parent colony, we shall see that 

 both F. rufa and F. exsecta occasionally succeed in bringing up 

 their families with the aid of F. fusca. 



The case of F. truncicola, a continental subspecies, is already 

 clear. Three mixed colonies with F. fusca have been found 

 by Wasmann, two in Luxemburg and one in Saxony, in addition 

 to the one found by Forel. Wasmann, on March 22nd, 1908, 

 found at Luxemburg a young truncicola colony in a pure fusca 

 type of nest, where there w^as no fusca present. On April 15th 

 they had moved and built a true truncicola nest. He states 

 that a truncicola female regularly grounds her new colony, with 

 the help of fusca, after the marriage-flight, by entering a fusca 

 nest. 



