46 



each other. On April 15th the F. rufa female died, but not 

 from violence. 



We do not wish here to enter upon the vexed question of 

 the origin of the slave-making instinct and its connection with 

 the habit of Temporary Social Parasitism, but there seems 

 clear evidence that the raiding habit of F. rufa workers shows 

 itself occasionally in the females. It is well known that F. 

 rufa will attack nests of other ants and pillage their brood, and 

 in some cases will even rear the latter. Crawley has shown 

 that F. rufa colonies in captivity will carry off pupse of their 

 own species, of F. sanguínea, F. fusca and its races, L. niger 

 and L. flavus, but seldom those of Myrmica. These pupa;, 

 especially those of L. flavus and L. niger females, were often 

 kept for weeks, but eventually eaten. In May 191 2, however, a 

 captive colony of F. rufa carried in over a dozen female pupae 

 of F. sanguínea, very few of which were devoured. On July 8th 

 one hatched, and the young female was carefully extracted 

 from the cocoon and cleaned, but no sooner was she able to 

 walk than the workers began to attack her, eventually killing her. 

 Crawley had a colony of F. sanguínea from WelHngton College, 

 in 1908, which, in addition to the ordinary F. fusca slaves, pos- 

 sessed a number of F . rufa slaves, hatched from pupae carried 

 in b}^ the F. sanguínea workers. In 191 1 a strong F. rufa 

 colony from Porlock was placed on the same tray. Some of 

 the workers from this colony entered the F. sanguínea nest, 

 where they were unmolested, owing perhaps to the F. sanguínea 

 workers having become accustomed to the presence of F. rufa 

 in their nest. Next day the new F. rtifa colony invaded the 

 F. sanguínea nest and kidnapped all the F. rufa slaves be- 

 longing to the latter, and carried them to their own nest. They 

 also carried in a number oi F. sanguínea workers, who allowed 

 themselves to be taken without resistance. The following day 

 the kidnapped F. sanguínea were found dead and thrown out 

 of the nest, but the captured F. rufa workers were at home in 

 their new quarters. 



Wasmann records in 1909 that he had two F. rufa females 

 which robbed the pupae from a weak F. fusca nest and assisted 

 the callows to hatch. In June 1912 Crawley placed three 

 F. rufa females in the fourth chamber of a four-chambered 



