'ó9 



other. Soon after its establishment workers of the Weybridge 

 colony were seen at the door of the Porlock nest, and on April 2nd, 

 IQ12, the Weybridge workers were found busily tran^J orting 

 their own females, workers, and brood to the Porlock nest, where 

 they were received without hostility. Next da}- the two colonies 

 were amalgamated, but though there were no fights between the 

 workers, three females were eventually killed. Thus queens 

 from both colonies were killed, but not a single worker. This 

 suggests that it is possible for a large colony of this species 

 completely to absorb a smaller and weaker one. 



There is, however, another way in which colonies (,i F. rufa 

 and F. exsecta groups are founded, and that is by what is now 

 known as " Temporary Social Parasitism." The female seeks 

 out a colony, generali}' queenless, of F. fusca and its races 

 and is adopted by the workers, who bring up her brood. The 

 colony eventually becomes a pure one of the female's species, 

 owing to the natural death, in due course, of the host workers. 

 To Professor Wheeler is due the credit of this discovery, which 

 he has confirmed by many experiments. The number, however, 

 of such incipient mixed colonies that have actually been found 

 in nature is very small. In July 1871 Forel found, near to 

 Loco (Tessin), under a stone, a colony consisting of three-quarters 

 fusca workers and one-quarter truncicola workers, with larvae 

 and cocoons of the latter. Apparently he did not see the queen, 

 which would have run underground. About the same time he 

 found a small nest of exsecto-pvcssilabris containing a certain 

 number of fusca workers. In both these cases there was the 

 utmost friendliness between the two species. Again in August 

 of the same year he found a mixed colon\- of pratensis and fusca 

 with a number of small cocoons in the nest. Wasmann found 

 an incipient colony of the same two species in Holland. 



That these mixed colonies represented a regular mode of 

 colony-founding was, however, unsuspected until Wheeler, 

 closely followed b}- WAS^L\N^■, formulated his theor}- of Tem- 

 porary Social Parasitism in 1904. He fcnrnd nian\- mixtd colonies 

 consisting of females of the North American F. consocians and 

 workers of the timid F . incerta, and concluded that a \'oung fer- 

 tilised female of the former entered small incipient or depauperated 

 colonies of the latter, induced the workers to accejtt hir, and U) 



