INSTINCT OF INSECTS. 569 



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 sub- 

 stance ; 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 considerable 

 distance, as though they foresaw the inconveniences which might result 

 from another mode of construction. 1 However difficult it may be to form 

 a clear conception of this union of instinct and reason in the same opera- 

 tion, 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 reasoci that directs " an old greyhound 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 decidedly, 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 airopos), 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 similar defensive ex- 

 pedient 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 in- 

 stinct was chiefly concerned, if we impartially consider 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 entrance should 

 have been barricadoed. But it appears clear, from the statement of 

 Huber, that it was not until the hives had been repeatedly attacked and 

 robbed of nearly their whole stock of honey, that the bees betook them- 

 selves to the plan so successfully adopted for the security of their remain- 

 ing treasures ; so that reason, taught by experience, seems to have called 

 into action their dormant instincts. 3 



If it be thus probable that reason has some influence upon the actions 

 of insects which must be mainly regarded as instinctive, the existence of 

 this faculty is still more evident in numerous traits of their history where 

 instinct is little if at all concerned. An insect is taught by its instincts 

 the most unerring means to the attainment of certain ends ; but these 

 ends, as I have already had occasion more than once to remark, are 

 limited in number, and such only as are called for by its wants in a state 

 of nature. We cannot reasonably suppose insects to be gifted with 

 instincts adapted for occasions that are never likely to happen. If, 



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



s Huber, ii. 289. 



