Chap. Vlli.] OP NATURAL SELECTION. 35t 



as instinct alone is concerned, the wonderful difference 

 in this respect between the workers and the perfect 

 females, would have been better exemplified by the hive- 

 bee. If a working ant or other neuter insect had been 

 an ordinary animal, I should have unhesitatingly as- 

 sumed that all its characters had been slowly acquired 

 through natural selection; namely, by individuals hav- 

 ing been bom with slight profitable modifications, 

 which were inherited by the offspring; and that these 

 again varied and again were selected, and so onwards. 

 But with the working ant we have an insect differing 

 greatly from its parents, yet absolutely sterile; so that it 

 could never have transmitted successively acquired 

 modifications of structure or instinct to its progeny. It 

 may well be asked how is it possible to reconcile this 

 case with the theory of natural selection? 



First, let it be remembered that we have innumera- 

 ble instances, both in our domestic productions and in 

 those in a state of nature, of all sorts of differences of in- 

 herited structure which are correlated with certain ages, 

 and with either sex. We have differences correlated 

 not only with one sex, but with that short period when 

 the reproductive system is active, as in the nuptial 

 plumage of many birds, and in the hooked jaws of the 

 male salmon. We have even slight differences in the 

 horns of different breeds of cattle in relation to an arti- 

 ficially imperfect state of the male sex; for oxen of cer- 

 tain breeds have longer horns than the oxen of other 

 breeds, relatively to the length of the horns in both the 

 bulls and cows of these same breeds. Hence I can see 

 no great difficulty in any character becoming correlated 

 with the sterile condition of certain members of insect - 

 communities: the difficulty lies in understanding how 



