414 



INSTINCT OF INSECTS. 



there being nothing in hollow trees (their natural abodes) re- 

 sembling 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 before changing the 

 direction of the comb, but adopted this variation at a con- 

 siderable distance, as though they foresaw the inconveniences 

 which might result from another mode of construction. 1 How- 

 ever difficult it may be to form a clear conception of this 

 union of instinct and reason 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 grey- 

 hound to trust the more fatiguing part of the chase to the 

 younger, and to place himself so as to meet the hare in her 

 doubles." 2 



As another instance of these mixed actions in which both 

 reason and instinct seem concerned, but the former more de- 

 cidedly, may be cited the account which Huber gives of the 

 manner in which the bees of some of his neighbours protected 

 themselves against the attacks of the death's head moth 

 (Acherontia atropos), laid before you in a former letter, by so 

 closing the entrance of the hive with walls, arcades, casements, 

 and bastions, built of a mixture of wax and propolis, that these 

 insidious marauders could no longer intrude themselves. 



We can scarcely attribute these elaborate fortifications to 

 reason simply ; for it appears that bees have recourse to a si- 

 milar defensive expedient when attacked even by other bees, 

 and the means employed seem too subtle and too well adapted 

 to the end to be the result of this faculty in a bee. 



But, on the other hand, if it be most probable that in this 

 instance instinct was chiefly concerned, if we impartially con- 

 sider the facts, it seems impossible to deny that reason had 

 some share in the operations. Pure instinct would have 

 taught the bees to fortify themselves on the first attack. If 

 the occupants of a hive had been taken unawares by these 

 gigantic aggressors one night, on the second, at least, the en- 

 trance should have been barricadoed. But it appears clear, 



1 Huber, ii. 219. 2 Hume's Essay on the Reason of Animals, 



