THE APHIS. 



INDIVIDUALLY the aphis is insignificant; collectively 

 the aphides are a mighty army working incessant 

 damage to man. Whether the locust, the caterpillar, or the 

 aphis effects the greatest injury upon the vegetation neces- 

 sary to man's existence is a moot point. Were the locust 

 to be found in all parts of the world, instead of being con- 

 fined within comparatively limited regions, the palm would 

 certainly be awarded to it, for the locust spares nothing, 

 and destroys every green thing as its armies march along. 

 The caterpillar and the aphis, although far more widely 

 distributed, are less universal in their tastes, and fortunately 

 neither of them has any partiality for cereals, the great staple 

 of man's food. It may well be believed, however, that were 

 it not that the caterpillar is kept down by the ichneumon, and 

 the aphis by the ladybird and other foes, both would in a very 

 short time multiply so vastly that having devoured every 

 other green thing they would be driven to fall upon the 

 corn crops in their green stage ; for when approaching ripe- 

 ness the cereals are far too hard for mastication even by 

 the jaws of the caterpillar, while the aphis might as well 

 endeavour to obtain sustenance from a stone-wall. It is 

 needless, however, here to enter into a detailed considera- 

 tion as to the respective merits, or rather demerits, of the 



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