INSTINCT OF INSECTS. 



401 



him no very easy task — a task, in short, which it may be 

 doubted if he would satisfactorily perform in a twelvemonth, 

 though gifted with a clear head and a competent store of 

 geometrical knowledge, and which, if destitute of these re- 

 quisites, it may be safely asserted that he would never per- 

 form at all. How then can we imagine it possible that this 

 difficult problem, and others of a similar kind, can be so com- 

 pletely and exactly solved by animals of which some are not 

 two days old, others not a week, and probably none a year ? 

 The conclusion is irresistible — it is not reason but instinct 

 that is their guide. 



The second head, under which I proposed contrasting the 

 instinct of insects with those of the larger animals, was that 

 of their number in the same individual. In the latter this is 

 for the most part very limited, not exceeding (if we omit 

 those common to almost all animated beings) eight or ten 

 distinct instincts. Thus in the common duck, one instinct 

 leads it at its birth from the egg to rush to the water ; another 

 to seek its proper food ; a third to pair with its mate ; a 

 fourth to form a nest; a fifth to sit upon its eggs till 

 hatched; a sixth to assist the young ducklings in extricating 

 themselves from the shell; and a seventh to defend them 

 when in danger until able to provide for themselves : and it 

 would not be easy, as far as my knowledge extends, to add 

 many more distinct instinctive actions to the enumeration, or 

 to adduce many species of the superior classes of animals en- 

 dowed with a greater number. 



But how vastly more manifold are the instincts of the 

 majority of insects ! It is not necessary to insist upon those 

 differences which take place in the same insect in its different 

 states, leading it to select one kind of food in the larva and 

 another in the perfect state — to defend itself in one mode in 

 the former, and in another in the latter, &c. ; because, 

 however remarkable these variations, they may be referred 

 with great plausibility to those striking changes in the 

 organic structure of the animal which occur at the two 

 periods of its existence. It is to the number of instincts 

 observable in the same individual of many insects in their 

 perfect state that I now confine myself ; and as the most 



VOL. II. I> I) 



