414 THE LIFE OF AN INSECT. 



probability without being aware of the reasons 

 why it should do so. How can it tell that its 

 future progeny will eat this food, or that food? 

 How can the poor blow-fly, when it leaves its eggs 

 on our food, be certain that it is appointing a 

 suitable place for the birth-spot of its progeny ? 

 Why does it not select the green surface of the 

 leaf, or the warm corner of the window, or the 

 bare earth, for this purpose ? We might say, 

 perhaps, in this instance, that the insect is only 

 choosing the place where it obtains its own food. 

 . But what shall we say when we find insects, such 

 as the butterfly, depositing their eggs upon plants 

 which they never frequent at any other time, and 

 from which they never obtained a particle of food 

 themselves ? Some, for instance, deposit them on 

 the nettle, although never tasting anything from 

 this plant themselves, while the young which are 

 to proceed forth from the eggs feed voraciously 

 upon it. 



We cannot, in any way but one, account for 

 this forethought. The poor insect, left to itself, 

 would undoubtedly deposit its eggs indifferently 

 anywhere ; arid the result would be, that its 

 young family, if hatched at all, would awake 



