AFFECTION OF INSECTS FOR THEIR YOUNG. 289 



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 circum- 

 stance 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 in- 

 stance 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 instinctive 

 forbearance almost miraculous ? 



Some Ichneumons, instead of burying their eggs in the 

 body of the larvae that are to serve their young for food, con- 

 tent themselves with gluing them to the skin of their prey. 

 This is the case with Scolia flavifrons, which my learned 

 entomological friend M. Passerini of Florence has found places 

 its eggs on the larva of a large beetle ( Oryctes nasicornis), upon 

 which when hatched the larva of the Scotia feeds, by intro- 

 ducing the three first segments of its body into the belly of 

 its victim, always between the sixth and seventh segment, so 

 that this insect is a semi-internal parasite.^ Another tribe, 



* Osservazioni sulle Larve, Ninfe, 8fc. (Pise, 1840). Guerin-Meneville, Revue 

 Zoolog. 1841, p. 240. 



VOL. I. U 



