26 INTRODUCTION. 



of his attention must be occupied in prosecuting experiments 

 for the piu-pose of discovering how this or that insect enemy 

 may be combated in the most successful manner. And, in- 

 deed, it must be admitted, that this is a charge too well 

 founded, although, perhaps, a few observations may con- 

 vince those who are the most ready to bring it forward upon 

 every opportunity, that it may be greatly palliated. In the 

 first place, therefore, it may be urged, that these destructive 

 insects, appearing as they do in occasional seasons in vast 

 profusion, are produced in such myriads for some wise pur- 

 pose, which we may not be permitted to understand. They, 

 like the locusts, of which so splendid a poetical description 

 is recorded in the second chapter of the prophet Joel, form 

 a portion of the army of the Almighty wherewith He scourges 

 the nations ; and, although the scientific researches of man- 

 kind might discover means of destroying, in some degree, 

 these hosts, it may perhaps not unreasonably be supposed 

 either that he would not be allowed to frustrate the designs 

 of Providence, or that, if this evil were removed, others per- 

 haps more weighty might arise in their stead. In the second 

 place, the minuteness of the size of these creatures presents 

 an almost insurmountable barrier against those delicate in- 

 quiries and examinations of them, during every state of their 

 existence, by which alone we can arrive at a knowledge of 

 the real nature and cause of the mischief, and be thereby, 

 and thereby alone, enabled to judge of a suitable remedy. 

 In the third place, the want of a sufficient opportunity for 

 such researches is not the least objection which may be brought 

 against the charge. It must be admitted, that no effectual 

 check can be given to the ravages of any species of noxious in- 

 sect, until its entire habits and economy have been ascertained. 

 Thus far in the inquiry is the strict province of the entomolo- 

 gist, whose attention ought to be directed from day to day, and 

 from year to year, not to isolated spots of ground, but to whole 



