Heredity of Instincts. 29 



itself is, by its structure, intermediate between the honey and the 

 humble-bee, though more closely allied to the latter. It constructs a 

 comb of wax, almost regular, consisting of cylindrical cells, in which 

 the larvae are hatched, and a certain number of large cells to hold 

 its store of honey. The latter cells are nearly spherical, and situated 

 at a considerable distance from each other. Now, it has been 

 calculated that if the melipona were to construct these cells at 

 equal distances, and all of one size, if she were to arrange them 

 symmetrically in two layers, the result would be a structure as per- 

 fect as the hive of the honey-bee. ' Hence we may safely conclude,' 

 says Darwin, ' that if we could slightly modify the instincts already 

 possessed by the melipona, and in themselves not very wonderful, 

 this bee would make a structure as wonderfully perfect as that of 

 the hive-bee.' 



Since natural selection acts only by accumulating slight varia- 

 tions of organization or of instinct, which may be advantageous 

 to the individual, the question arises, How comes it that the succes- 

 sive and gradual variations of the constructive instinct, rather than 

 of any other instinct, should have by degrees formed the architec- 

 tural talent of the honey-bee ? Darwin's answer is ' The bee must 

 consume a great amount of honey in order to secrete a small 

 quantity ' of wax ; and during the winter it lives on its honey. 

 Whatever tends to make a saving of wax will also tend to save 

 honey, and so will be of service to the future of the hive.' If, now, 

 we suppose that the humble-bee hibernates, it will need a great 

 quantity of honey ; consequently every modification of instinct, 

 which would lead them to construct cells so near each other as to 

 have a parti-wall, would save some little wax, and so be of ad- 

 vantage to them. Hence it would continually be more and more 

 advantageous to the humble-bees if they were to make their cells 

 more -and more regular, nearer together, and aggregated into a 

 mass, like the cells of the melipona. ' So, too, it would be advan- 

 tageous to the melipona if she were to make her cells closer 

 together, thus approaching the perfect comb of the honey-bee. 

 Thus the most wonderful of all known instincts, that of the hive- 

 bee, can be explained by natural selection having taken 

 advantage of numerous successive slight modifications of simpler 

 instincts.' J 



1 Origin of 'Species ; ch. vii. 



