254- INDIRECT BENEFITS DERIVED FROM INSECTS. 



knows what dreadful miasmata exhale from them, and 

 taint the air we breathe. But no sooner does life depart 

 from the body of any creature, at least of any which from 

 its size is likely to become a nuisance, than myriads of 

 different sorts of insects attack it, and in various ways. 

 First come the Histers and pierce the skin. Next follow 

 the flesh-flies, some, that no time may be lost, (as Musca 

 carnaria, &c.) depositing upon it their young already 

 hatched 3 ; others (M. Ccesar, &c.) covering it with mil- 

 lions of eggs, whence in a day or two proceed innumerable 

 devourers. An idea of the dispatch made by these gour- 

 mands may be gained from the combined consideration 

 of their numbers, voracity and rapid development. One 

 female of M. carnaria will give birth to 20,000 young; 

 and the larvae of many flesh-flies, as Redi ascertained, will 

 in twenty-four hours devour so much food, and grow so 

 quickly, as to increase their weight two hundred fold ! In 

 five days after being hatched they arrive at their full 

 growth and size, which is a remarkable instance of the 

 care of Providence in fitting them for the part they are 

 destined to act : for if a longer time was required for their 

 growth, their food would not be a fit aliment for them, or 

 they would be too long in removing the nuisance it is 

 given in charge to them to dissipate. Thus we see there 

 was some ground for Linne's assertion under M. vomi- 

 toria, that three of these flies will devour a dead horse 

 as quickly as would a lion. 



As soon as the various tribes of Muscse have opened 



the way, and devoured the softer parts, a whole host of 



beetles, Necrophori, Silphce, Dermestes, Cholevce, and Sta- 



phylinidce, actively second their labours. Wasps and 



a Plate XXII. Fig, 4, 5. 



