PREVENTIVES AND REMEDIES. 159 



may be heated to 190 of Fahrenheit's scale without 

 losing its germinating power, and this is sufficient to 

 kill all the insects contained in it. 



It is an interesting fact that in all this ceaseless 

 crusade against the destructive insect tribes, Nature 

 is ever cooperating with man. In the order of Provi- 

 dence, some races of the animal creation are appointed 

 to arrest the growth and progress of others ; thus lim- 

 iting the results of excessive fecundity, which, if not 

 restrained, would soon cause the earth to be overrun 

 and monopolized by a few prolific tribes to the exclu- 

 sion of all others. Natural history everywhere abounds 

 with curious illustrations of this marvellous law, by 

 which the equilibrium of the animal -kingdom is stead- 

 ily and mysteriously preserved. 



" Many of the almost unheeded insects," says Levi 

 Bartlett, in a communication to the Country Gentle- 

 man, " that flit about the farmer's feet, as he traverses 

 his acres, are truly his friends and agents in destroy- 

 ing other species that are so injurious to his crops. 

 The first named should be protected, the latter should 

 be destroyed, in all their three-fold stages, as far as 

 possible. But without some knowledge of the science 

 of entomology, no one can discriminate, to any great 

 extent, between his insect friends and foes. Most of 

 the tiger-beetles should b'e protected by the farmer 

 while the May-beetle, and others of his like, should be 

 crushed beneath the foot, even if it should 'feel a 

 pang as great as when a giant dies.' ' : 



But of all the agents that cooperate with the 

 farmer in his warfare upon injurious insects, there are 



