ON THE FOUNDING OF NESTS BY ANTS. 83 



the 2 tapped it hard with her antennte and stroked it briskly on both 

 sides of the head with her front feet. February 6th the $ was attacked 

 by a ^ , which eventually she killed. February 7th, as half the ^ s 

 remained in the other partition of the nest, I put the ? and the ^ s 

 with her into a small plaster nest with only one compartment, and 

 gradually introduced the remaining '^ s. One of these persisted in 

 attacking her, and, after fighting with it all day, both rolling over and 

 over, she killed it in the evening. By February 9th I had introduced 

 all the S s into this very small nest ; they are now all quite friendly, 

 and the ? sits on and among them in a corner. They clean her legs 

 and body and feed her. To-day, February 24th, having given them 

 some honey, at which nearly all the ^ s fed, the J was afterwards fed 

 by some of them. It is, therefore, quite clear that if this ? will lay 

 eggs the larvfe will be brought up by these strange ^ s. It also confirms 

 the fact that ^ s of the F. fusca group will accept a strange F. rufa ? . 



In the event of a F. saiKjuinea queen entering a strange F. fusca 

 nest, she takes possession of the pupse, fights with, drives away, or 

 kills, the F. fnaca ^ s, and, when the F. fusca pupne hatch, they help her 

 to bring up her brood. The mixed character of the nest is kept up by 

 slave raids on other F. fiisca nests. I carried out some experiments 

 last year with F. mwiulnea ^ s, and these I recorded in detail in a 

 paper on " Experiments with Ants' nests," which I read before the 

 Entomological Society of London on December 1st, 1909. 



In the two experiments which were successful {i.e., in which the 

 F. nawjHinea $ was not killed), the $ s killed all the F. fusca ^ s in the 

 nests into which I introduced them, and took possession of the F. fusca 

 -cocoons, and sat on them in a corner of the nest. These two experi- 

 ments also confirmed what had been recorded about F. sanguinea. 



Formica e.vsecta appears to generally found its colonies, according 

 to Wasmann, with F. fusca. The $ F. e.vsecta is smaller in compari- 

 son with her ^ s than is the case with the rest of the F. rufa group, and 

 is of a darker colour, and would thus be more easily accepted by the 

 F. fusca ^ s. Wheeler has also shown this to be the case with the F. 

 -exsecta race in America. Forel, however, has recorded that it also forms 

 colonies by branch nests, where the species is numerous and many 

 nests are found together. This was probably the case at Bournemouth, 

 where I found manj' F. e.vsecta nests all together, but in the Isle of 

 Wight, and at Aviemore in the Highlands, where I discovered this rare 

 species, the former method was probably that used. At Parkhurst 

 Forest the few nests were in the ground, and with very little nest 

 materials built on them, suggestive of a recent fusca origin. At Avie- 

 more, two nests close together were of the usual e.vsecta type, built up 

 of grass and ling, but the third, which was a mile or two away, was 

 partly under a large stone, a heap of the nest material being built up 

 on one side. Under the stone were galleries such as are constructed 

 by F. fusca. 



Lasius umbratus is said sometimes to found its colony in a nest of 

 L. )ii;ier. Mr. Crawley records that he had a $ L. umbratus accepted 

 by a L. ni/jer nest {Knt. Mo. Ma;/., 1909, p. di), which agrees with 

 this view. 



Lasius fulit/inosus, which is often very numerous in a district in 

 which it occurs, partly founds its colonies by branch nests. Wasmann 

 has pointed out, however, that nests of Lasins umbratus are frequently 



