2 INTRODUCTION. 



many accidents through the influence of the elements, and 

 they fall a prey to numerous animals, many of them also 

 of the insect race, which, while they fulfil their own part 

 in the economy of nature, contribute to prevent the undue 

 increase of the noxious tribes. Too often, by an unwise 

 interference with the plan of Providence, we defeat the 

 very measures contrived for our protection. We not only 

 suffer from our own carelessness, but through ignorance 

 fall into many mistakes. Civilization and cultivation, in 

 many cases, have destroyed the balance originally exist- 

 ing between plants and insects, and between the latter and 

 other animals. Deprived of their natural food by the 

 removal of the forest trees and shrubs, and the other 

 indigenous plants that once covered the soil, insects have 

 now no other resource than the cultivated plants that have 

 taken the place of the original vegetation. The destruc- 

 tion of insect-eating animals, whether quadrupeds, birds, 

 or reptiles, has doubtless tended greatly to the increase of 

 insects. Colonization and commerce have, to some extent, 

 introduced foreign insects into countries where they were 

 before unknown. It is to such causes as these that we 

 are to attribute the unwelcome appearance and the undue 

 multiplication of many insects in our cultivated grounds, and 

 even in our store-houses and dwellings. We have no reason 

 to believe that any absolutely new insects are generated or 

 created from time to time. The supposed new species, made 

 known to us first by their unwonted depredations, may have 

 come to us from other parts, or may have been driven by the 

 hand of improvement from their native haunts, where here- 

 tofore the race had lived in obscurity, and thus had escaped 

 the, notice of man. 



To understand the relations that insects bear to each other 

 and to other objects, and to learn how best to check the 

 ravages of the noxious tribes, we must make ourselves thor- 

 oughly acquainted with the natural history of these animals. 

 This subject is particularly important to all persons who are 



