132 HISTORY OF 



upon the substance of their prison. As they 

 grow larger, they require a greater supply, till at 

 last the animal by whose vitals they are support- 

 ed, is no longer able to sustain them, but dies, its 

 whole inside being almost eaten away. It often 

 happens, however, that it survives their worm 

 state, and then they change into a chrysalis, en- 

 closed in the caterpillar's body till the time of 

 their delivery approaches, when they burst their 

 prisons, and fly away. The caterpillar, however, 

 is irreparably destroyed ; it never changes into a 

 chrysalis, but dies shortly after, from the injuries 

 it had sustained. 



Such is the history of this fly, which, though 

 very terrible to the insect tribe, fails not to be of 

 infinite service to mankind. The millions which 

 it kills in a single summer are inconceivable ; 

 and without such a destroyer the fruits of the 

 earth would only rise to furnish a banquet for 

 the insect race, to the exclusion of all the nobler 

 ranks of animated nature. 



CHAPTER V. 



OF THE ANT. 



THOUGH the number of two-winged flies be very 

 great, and the naturalists have taken some pains 

 to describe their characters and varieties, yet 

 there is such a similitude in their forms and man- 

 ners, that, in a work like this, one description 



