220 MENTAL EVOLUTION IN ANIMALS. 



further remains to be said of these. If they occur similarly 

 and simultaneously in a large number of individuals, as may 

 be the case where the new adjustment is simple and obvious, 

 there may be no need of imitation to assist in changing the 

 instinct. But in other cases I am inclined to think that 

 imitation may play an important part in this matter. I must 

 confess, however, that in searching for evidence of one species 

 of animal imitating the beneficial habits of another, I have 

 been surprised at the rarity of its occurrence, although, as I 

 shall presently show, there is abundant evidence of one 

 { iiidwiclual imitating the habits of another individual — whether 

 of its own or of other species, and whether the action imitated 

 is beneficial or useless. This difference, I think, is probably 

 to be explained by the reflection that in all cases where such 

 imitation between species and species may have obtained in 

 the past, we should now only see an instinct common to the 

 two species, and therefore should have no evidence that it 

 was not always common. Consequently, it is only in cases 

 where the imitation by one species of the habits of another 

 is in its earlier phases that we can find evidence of the fact. 

 The following are the only cases of such imitation that I 

 have been able to meet with ; but to them I add a number 

 of cases of individual imitation, because this must evidently 

 form the groundwork of imitation among species. 

 I quote the following from Mr. Darwin's MSS : — 

 " From some experiments which I was making, I had 

 occasion very closely to watch some rows of the tall kidney- 

 bean, and I daily saw innumerable hive-bees alighting as 

 usual on the left wing-petel, and sucking at the mouth of the 

 flower. One morning, for the first time, I saw several 

 humble-bees (which had been extraordinarily rare all summer) 

 visiting these flowers, and I saw them in the act of cutting 

 with their mandibles holes through the under side of the 

 calyx, and thus sucking the nectar : all the flowers in the 

 course of the day became perforated, and the humble-bees in 

 their repeated visits to the flowers were thus saved much 

 trouble in sucking. The very next day I found all the hive- 

 bees, without exception, sucking through the holes which 

 had been made by the humble-bees. How did the hive-bees 

 find out that all the flowers were bored, and how did they so 

 suddenly acquire the habit of using the holes ? I never saw, 

 though I have long attended to the subject, or heard of hive- 



