INSTINCT AND INTELLIGENCE. 



that she has been forestalled by some precursor of her own tribe, 

 that has already buried an egg in the caterpillar she is examining. 

 In this case she leaves it, aware that it would not suffice for the 

 support of two, and proceeds in search of some other yet unoc- 

 cupied. The process is, of course, varied in the case of those 

 minute species, of which several, sometimes as many as 150, can 

 subsist on a single caterpillar. The ichneumon then repeats 

 her operation, until she has darted into her victim the requisite 

 number of eggs. 



51. The larvse hatched from the eggs thus ingeniously deposited, 

 find a delicious banquet in the body of the caterpillar, which is 

 sure eventually to fall a victim to their ravages. So accurately, 

 however, is the supply of food proportioned to the demand, that 

 this event does not take place until the young ichneumons have 

 attained their full growth, when the caterpillar either dies, or, 

 retaining just vitality enough to assume the pupa state, then 

 finishes its existence ; the pupa disclosing not a moth or a 

 butterfly, but one or more full-grown ichneumons. 



In this strange and apparently cruel operation one circumstance 

 is truly remarkable. The larva of the ichneumon, though every 

 day, perhaps for months, it gnaws the inside of the caterpillar, 

 and though at last it has devoured almost every part of it except 

 the skin and intestines, carefully all this time avoids injuring the 

 vital organs, as if aware that its own existence depends on that of 

 the insect on which it preys ! Thus the caterpillar continues to 

 eat, to digest, and to move, apparently little injured, to the last, 

 and only perishes when the parasitic grub within it no longer 

 requires its aid. What would be the impression which a similar 

 instance amongst the race of quadrupeds 

 would make upon us ? If, for example, 

 an animal such as some impostors have 

 pretended to carry within them should be 

 found to feed upon the inside of a dog, 

 devouring only those parts not essential 

 to life, while it cautiously left uninjured 

 the heart, arteries, lungs, and intestines, 

 should we not regard such an instance 

 as a perfect prodigy, as an example of in- 

 stinctive forbearance almost miraculous ? * 

 52 - The sexton-beetle, or Necrophorus 

 (fig. 13), when about to deposit its eggs, 

 takes care to bury with them the carcass of a mole or some 

 other small quadruped; so that the young, which, like the 



* Kirby, Int., vol. i., p. 288. 

 136 



