FOOD OF INSECTS. 401 



this case, as operates to prolong- the term of existence 

 of annual plants that have been prevented from per- 

 fecting their seed ; and it would almost seem to favour 

 the hypothesis of some physiologists, who contend that 

 every organized being has a certain portion of irrita- 

 bility originally imparted to it, and that its life will be 

 long or short as this is slowly or rapidly excited— ^no 

 great consolation this for the advocates for fast-living, 

 unless they are in good earnest in their affected prefe- 

 rence of a " short life and a merry one:" though it 

 must be admitted that they would have the best of the 

 argument were the alternative such a state of torpid 

 insensibility as that with which our larva purchased 

 the prolongation of its existence. 



After this general view of the food of insects, and of 

 circumstances connected with it, I proceed to give you 

 an account of some peculiarities in their modes of pro- 

 curing it. 



The vegetable feeders have for the most part but little 

 difficulty in supplying their wants. In the larva state 

 they generally find themselves placed by the parent in- 

 sect upon the very plant or substance which is to nou- 

 rish them ; and in their perfect state their wings or feet 

 afford a ready conveyance to the banquet to which by 

 an unerring sense they are directed. All nature lies 

 before them, and it is only when their numbers are ex- 

 traordinarily increased, or in consequence of some un- 

 usual destruction of their appropriate aliment, that they 

 perish for want. The description of their food renders 

 unnecessary those artifices to which many of the carni- 

 vorous insects are obliged to have recourse ; and none 



VOL. I. 2d 



