VARIATION OF INSTINCT IN DEFINITE LINES. 221 



bees themselves boring holes. Tlie minute holes made by 

 the humble-bees were not visible from the mouth of the 

 flower, where the hive-bees had hitherto invariably alighted : 

 nor do I believe, from some experiments wliich I have made, 

 that they were guided by the scent of the nectar escaping 

 through these orifices more readily than through the mouth 

 of the flower. The kidney-bean is also an exotic. I must 

 think that the hive-bees either saw the lmml)le-l)ees cutting 

 the holes, and understood what they were doing, and imme- 

 diately profited by tlieir labour ; or that they merely imitated 

 the liumble-bees after they had cut the holes, and when 

 sucking at them. Yet I feel sure that if anyone who had 

 not known this previous history had seen every single hive- 

 bee, without a moment's hesitation, flying with the utmost 

 celerity and precision from the under side of one flower to 

 another, and then rapidly sucking the nectar, he would have 

 declared that it was a beautiful case of instinct." 



Mr. Darwin in his MSS has also the following observa- 

 tions concerning the subject of imitation : — " It is difficult to 

 determine how much dogs learn by experience and imitation. 

 I apprehend tliere can be little doubt that the manner of 

 attack of the English Bull-dog is instinctive (Rollin, ' Mem., 

 &c.,' tom. iv, p. 339). I believe that certain dogs in South 

 America without education rush at the belly of the stag 

 which they hunt, and that certain other dogs when first 

 taken out run round the heads of Peccaris. We are led to 

 believe that these actions are imitative when we hear from 

 Sir J. Mitchell (' Australia,' vol. i, p. 292), that his dogs did 

 not learn how safely to seize the Emu by the neck, until the 

 close of his second expedition. On the other hand Mr. Couch 

 ('Illustrations of Instinct,' p. 191) gives the case of a dog 

 who learned, after a single battle with a Badger, the spot 

 where it would inflict a fatal bite, and it never forgot the 

 lesson. In the Falkland Islands it seems that the dogs 

 learned from each other the best way of attacking the wild 

 cattle (Sir J. Ross, * Voyage,' vol. ii, p. 246)." 



Again, Mr. Darwin points out that many species of wild 

 animals certainly learn to understand and to profit by the 

 danger cries and signals employed by other species, and this 

 is a kind of imitation.* He also adduces a good deal of 



* Thus, for instance, he says that "the inhabitants of the United States 

 like to have martins build on their houses, as their cry when a hawk 



