AFFECTION OF INSECTS FOR THEIR YOUNG. 341 



be to them poison, she is in search of some plant of the 

 cabbage tribe. But how is she to distinguish it from the 

 surrounding vegetables ? She is taught of God ! Led 

 by an instinct far more unerring than the practised eye 

 of the botanist, she recognises the desired plant the mo- 

 ment she approaches it, and upon this she places her 

 precious burthen ; yet not without the further precaution 

 of ascertaining that it is not preoccupied by the eggs of 

 some other butterfly ! Having fulfilled this duty, from 

 which no obstacle short of absolute impossibility, no 

 danger however threatening, can divert her, the affec- 

 tionate mother dies. 



This may serve as one instance of the solicitude of in- 

 sects for their future progeny. But almost every spe- 

 cies will supply examples similar in principle, and in 

 their particular circumstances even more extraordinary. 

 In every case (except in some remarkable instances of 

 mistakes of instinct, as they may be termed, which will 

 be subsequently adverted to) the parent unerringly di- 

 stinguishes the food suitable for her offspring, however 

 dissimilar to her own ; or at least invariably places her 

 eggs, often defended from external injury by a variety of 

 admirable contrivances, in the exact spot where, when 

 hatched, the larvae can have access to it. The dragon- 

 fly is an inhabitant of the air, and could not exist in wa- 

 ter : yet in this element, which is alone adapted for her 

 young, she ever carefully drops her eggs. The larvae of 

 the gad-fly ( GasteropJiilus Equi), whose history has been 

 before described to you 3 , are destined to live in the sto- 

 mach of the horse. How shall the parent, a two-winged 

 fly, convey them thither? By a mode truly extraor- 

 " P. 147, &c. 



