OF -NATURAL HISTORY. §95 



gradually thickens and grows harder, till it acquires the ufual 

 degree of firmnefs. By this time the animals have refum-ed 

 their former flrength and activity ; they come out from their 

 retirements, and go about in queft of food. 



Serpents, and many other reptiles, caft their f!dns an- 

 nually. The beauty and luftre of their colours are then 

 highly augmented. Before cafting, the old flcins have a 

 tarnilhed and withered appearance. The old fiiins, like 

 the firft fet of teeth in children, are forced ofFby the grovv-th 

 of the new. 



We come now to give fome account of the transformations 

 of infccfs^ which are both various and wonderful. All wing- 

 ed infe(fts, without exception, and many of thofe which are 

 deflitute of wings, muft pafs through feveral changes before 

 the animals arrive at the perfe6lion of their natures. The 

 appearance, the ftrudlure, and the organs of a caterpillar, of 

 a chryfalis, and of a fly, are fo different, that, to a perfon un- 

 acquainted with their transformations, an identical animal 

 would be confidered as three diftincl fpecies. Without the 

 aid of experience, who could believe that a butterfly, adorn- 

 ed with four beautiful wings, furnillied w^ith a long fpiral 

 probofcis or tongue, inftead of a mouth, and with fix legs, 

 fliould have proceeded from a difgufting, hairy caterpillar, 

 provided with jaws and teeth, and fourteen feet ? Without 

 experience, who could imagine that a long, white, finooth, 

 foft worm, hid under the earth, fliould be transformed into 

 a black, cruftaceous beetle, having wings covered with horny 

 tflytra, or cafes ? 



Upon this branch of the fubject, we fhall,/r/?, give an ex- ' 

 ample or two of the moft common transformations of In- 

 fects ; and, fecofidly, defcribe fome of the more uncommon 

 kinds. 



Befide their final metamorphofis into flies, caterpillars un- 

 dergo feveral intermediate changes. All caterpillars caft or 



