9 
INTRODUCTION. 
many accidents throuMi the influence of the elements, and 
they fall a prey to nmnerous animals, many of them also 
of the insect race, wliich, while they falfil their own part 
in the economy of nature, contribute to preyent the midue 
increase of the noxious tribes. Too often, by an unwise 
interference with the plan of Prorfdence, we defeat the 
yery measures contriyed for our protection. AVe not only 
suffer from our oym carelessness, but throuo:h ionorance 
fall into many mistakes. Cirflization and cultivation, in 
many cases, haye destroyed the balance originally exist¬ 
ing between plants and insects, and between the latter and 
other animals. Depriyed of their natural food by the 
remoyal of the forest trees and shmbs, and the other 
indigenous plants that once coyered the soil, insects haye 
now no other resource than the cultiyated plants that haye 
taken the place of the original vegetation. The destruc¬ 
tion of insect-eating animals, whether quadmpeds, birds, 
or reptiles, has doubtless tended gi’eatly to the increase of 
insects. Colonization and commerce have, to some extent, 
introduced foreimi insects into countries where they were 
before unknovm. It is to such causes as these that we 
are to attribute the unwelcome appearance and the undue 
multiplication of many insects in our cultiyated grounds, and 
eyen in our store-houses and dwellings. ^Ve haye no reason 
to belieye that any absolutely new insects are generated or 
created fi’om time to time. The supposed new species, made 
known to us first by them unwonted depredations, may haye 
come to us from other parts, or may haye been driven by the 
hand of improvement fr’om their native haunts, where here¬ 
tofore the race had lived in obscmlty, 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 
