268 T H E P H I L O S O P H Y 



The oeconomy and manners of infeds are more open to infpec- 

 tion. Thofe of the winged tribes undergo many changes, both in 

 figure and ftrudture, before they arrive at the age of puberty. They 

 firft. efcape from the eggs in the form of minute caterpillars. In this 

 ftate they are exceedingly voracious, and grow with rapidity to their 

 full fize ; but they are deftitute both of the power and of the organs 

 neceflary for the multiplication of the fpecies. They are next tranf- 

 formed into chryfalids : In this ftate, their bodies are covered 

 with a kind of cruft or Ihell, from which the animals have again to 

 efcape, as from a fecond egg. In this imprifoned condition, they 

 remain during a longer or ftiorter period, according to the fpecies, 

 or to the feafon of the year in which they are transformed. After 

 their transformation into flies, they burft this cruft or ftiell, and ap- 

 pear in the form of flies, furnifhed with wings, legs, feelers, &c. of 

 all which they were deftitute in their former ftate. When tranf- 

 formed into flies, caterpillars have arrived at the age of puberty. 

 They are now perfedl animals, and endowed with, the faculty of 

 tranfmitling a numerous progeny to pofterity. 



CHAP. 



