INSTINCT OF INSECTS. 509 



tion in an animal whose term of life does not exceed two 

 years. 



It does not follow, however, that reason may not have 

 a part in inducing some of these last-mentioned actions, 

 though the actions themselves are purely instinctive. I 

 do not pretend to explain in what way or degree they are 

 combined ; but certainly some of the facts do not seem to 

 admit of explanation, except on this supposition. Thus, 

 in the instance above cited from Huber, in which the 

 bees bent a comb at right angles in order to avoid a slip 

 of glass, the remarkable variations in the form of the 

 cells can only, as I have there said, be referred to in- 

 stinct. Yet the original determination to avoid the glass 

 seems, as Huber himself observes, to indicate something 

 more than instinct, since glass is not a substance against 

 which Nature can be supposed to have forewarned bees, 

 there being nothing in hollow trees (their natural abodes) 

 resembling it either in polish or substance : and what was 

 most striking in their operations was, that they did not 

 wait until they had reached the surface of the glass be- 

 fore changing the direction of the comb, but adopted this 

 variation at a considerable distance, as though they fore- 

 saw the inconveniences which might result from another 

 mode of construction ^ — However difficult it may be to 

 form a clear conception of this union of instinct and rea- 

 son in the same operation, or to define precisely the limits 

 of each, instances of these mixed actions are sufficiently 

 common among animals to leave little doubt of the fact. 

 It is instinct which leads a greyhound to pursue a hare ; 

 but it must be reason that directs " an old greyhound to 

 trust the more fatiguing part of the chase to the younger, 

 ' Huber, ii. 219. 



