INJURIOUS INSECTS. 
33 
do not know that we have any evidence of the destruction or 
serious injury of American forests by insects, before or even 
soon after the period of colonization ; but since the white man 
has laid bare a vast proportion of the earth’s surface, and 
thereby produced changes favorable, perhaps, to the multipli¬ 
cation of these pests, they have greatly increased in numbers, 
and, apparently, in voracity also. Not many years ago, the 
pines on thousands of acres of land in North Carolina, were 
destroyed by insects not known to have ever done serious 
injury to that tree before. In such cases as this and others of 
the like sort, there is good reason to believe that man is the 
indirect cause of an evil for which he pays so heavy a penalty. 
Insects increase whenever the birds which feed upon them 
disappear. Hence, in the wanton destruction of the robin and 
other insectivorous birds, the bipes implumis , the featherless 
biped, man, is not only exchanging the vocal orchestra which 
greets the rising sun for the drowsy beetle’s evening drone, 
and depriving his groves and his fields of their fairest orna¬ 
ment, but he is waging a treacherous warfare on his natural 
allies.* 
eral employment of the Robinia to clothe and protect embankments and 
the scarps of deep cuts on railroads, it would do incalculable mischief. As 
a traveller, however, I should find some compensation for this evil in the 
destruction of these acacia hedges, which as completely obstruct the view 
on hundreds of miles of French and Italian railways, as the garden -walls 
of the same countries do on the ordinary roads. 
* In the artificial woods of Europe, insects are far more numerous and 
destructive to trees than in the primitive forests of America, and the same 
remark may be made of the smaller rodents, such as moles, mice, and 
squirrels. In the dense native wood, the ground and the air are too 
humid, the depth of shade too great for many tribes of these creatures, 
while near the natural meadows and other open grounds, where circum¬ 
stances are otherwise more favorable for their existence and multiplica¬ 
tion, their numbers are kept down by birds, serpents, foxes, and smaller 
predacious quadrupeds. In civilized countries, these natural enemies of 
the worm, the beetle and the mole, are persecuted, sometimes almost ex¬ 
terminated, by man, who also removes from his plantations the decayed 
or wind-fallen trees, the shrubs and underwood, which, in a state of 
nature, furnished food and shelter to the borer and the rodent, and often 
3 
