INDIRECT BENEFITS DERIVED FROM INSECTS. 257 



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 Sarco- 

 phaga camariaj &c.) depositing upon it their young al- 

 ready hatched*; others {Musca Ccesar, &c.) covering it 

 with millions of eggs, whence in a day or two proceed 

 innumerable devourers. An idea of the dispatch made 

 by these gourmands may be gained from the combined 

 consideration of their numbers, voracity and rapid de- 

 velopment. One female of S. 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 remark- 

 able 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 W. vomitoria, that three of these flies will 

 devour a dead horse as quickly as would a lion. 



As soon as the various tribes o^ Muscidcx;\\a.\e opened 

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

 beetles, Necroj)hori^ Silphce, Dermestcs, Cholevcc, and Sta- 

 j)hylinid(p, actively second their labours. Wasps and 

 liornets also come in for their portion of the spoil ; and 

 " Platf. XXII.FiG. 4,5. 



VOL. I. S 



