272 SECRETS OF ANIMAL LIFE 



in considering the maternal care of some of the 

 worker-ants and worker-bees, who are normally 

 non-productive females. They mother the young 

 as if these were their own, and we explain this by 

 the natural supposition that this capacity dates 

 back to the time when all the females were normally 

 mothers, before the communal life with its marked 

 division of labor was established. It may be re- 

 membered that fertile workers occasionally occur, 

 and that a worker grub can be nurtured into a 

 queen. We cannot suppose that the workers simply 

 inherit their nursing capacities from their mother 

 the queen for she does not exhibit the qualities 

 required, being specialized for sheer maternity. We 

 must go much farther back. Another illustration 

 of our argument may be found in a widely different 

 sphere in the case of the European cuckoo. In a 

 somewhat elaborate way the mother-bird secures 

 the success of offspring to which she is herself a 

 stranger. Laying her egg on the ground, she takes 

 it in her mouth, flies with it down the hedgerow, 

 and puts it into the selected nest of a foster-parent, 

 and thus hits an unseen mark. The existence of 

 other kinds of cuckoo which show less perfect 

 evasion of parental duties convinces us that the 

 utilization of other nests and of foster-parents was 

 gradually evolved from a state of affairs in which 

 cuckoos reared their own young. The egg has 

 significance to the mother-cuckoo, who has no 

 experience of nestling or chick, because she belongs 

 to a race in which brooding was once the rule. 



