354 THE WONDER OF LIFE 



each escorted by a few soldier and worker termites. It 

 appears that the larvse exude a strong odour which is 

 attractive to the termites. Just as man may have flowers 

 in a room for the sake of their perfume, so the termites 

 have caterpillars. Chacun d son gout. 



In not a few cases, the fact of association is well estab- 

 lished, but its meaning remains obscure. Thus Mr. F. P. 

 Smith has reported the normal occurrence of a spider 

 (Thyreosthenius biovatus) in the nests of the wood-ant 

 (Formica rufa). The ants tolerate their guest, which they 

 could readily destroy, but what the spider is after remains 

 undiscovered. It is possible that it feeds on other inmates 

 of the ant-hill (the scavengers and pets) ; it is possible that 

 it eats the ' ants' eggs ' on the sly. There are two other 

 so-called ' myrmecophilous spiders ' in Britain on quite 

 a different footing from spiders found casually wandering 

 about on ant hills but the significance of the association 

 requires to be looked into. 



Slave -Making. If slave-keeping among ants occurred 

 once or twice, one might think it was some strange aberra- 

 tion among the little people, but there are many instances 

 and many stages of the 'institution'. 



A fertilized queen of the red ant, Formica sanguinea, 

 may fall after her nuptial flight into a nest of black ants, 

 Formica fusca, where there is no queen. She is received 

 and fed, and the eggs which she lays are tended. A mixed 

 colony arises, with the reds as masters and the blacks as 

 slaves, the former being more active in external operations 

 and the latter in the discharge of domestic duties. As 

 the blacks do not multiply, the reds make sallies and bring 

 back pupae from neighbouring nests of blacks. Those 

 that are not eaten grow up to slavery. Sometimes, how- 



