20 LETTERS ON ENTOMOLOGY. 
and whether our higher faculties are not brought 
more into play, and our mental powers more in- 
vigorated, by the meditation and experiments 
necessary to secure ourselves. Viewed in these 
lights, what was a*t first regarded as wholly made 
up of evil, may be discovered to contain a con- 
siderable proportion of good." 
A few facts will convince us of the justice of 
these remarks. In countries where vegetation is 
luxuriant, even the locusts are of use to clear away 
the superabundance of some individual species. 
Sparrman remarks, that a region which had been 
choked up by shrubs, perennial plants, and hard, 
half- withered and unpalatable grasses, after being 
made bare by these scourges, soon appears in a 
far more beautiful dress, clothed with new herbs, 
superb lilies, and fresh annual grasses, and young 
juicy shoots of the perennial kind, affording de- 
licious herbage for the wild cattle and game. 
When in moderate numbers, the grubs, which 
feed upon grass, only devour so much as to make 
room for new shoots, and consequently hinder 
the roots from being matted. There are many 
similar instances, but the ways in which they are 
most beneficial to us, are by removing all dead 
and decaying substances ; supplying food to use- 
ful animals, as fish and birds; and devouring 
