OF NATURAL HISTORY. 301 



fiance, tlie new infeft, furniflied with all its members, is 

 difcovered. But this dlfcovery does' not render the fa£t the 

 lefs wonderful. All winged infeiSls undergo their different 

 transformations after being expelled from the bodies of theii 

 rriothers, and receive great augmentations of lize before their 

 mttamorpncr^^ into the nymph or chryfiiMs ftate, after which 

 their growth (lops. But the fpider-fly ufFord-s an inftance 

 of an infecSl transformed in the belly of its mother, and 

 which grows no more after it eft^apes from its envelope. 

 This fa6l is fully authenticated by Reaumur*, Bonnetf , and 

 other naturalifls. 



The worm from which the tipula or crane-fly is produced 

 is perfe61:ly fmooth. Immediately before its fir ft transfor- 

 mation it retires under ground. After this metamorphofis, 

 tlie furface of the nymph is fnrniflied with a number of 

 prickles. By means of thefe prickles, the nymph, when 

 about to be transformed into a fly, raifes Itfelf in its hole till 

 the cheft of the infe^l is above ground. The fly then burfts 

 its prifon, mounts into the air, and leaves its former cover- 

 ing behind in the earth. 



Many fpecies of flies depofit their eggs in the leaves and 

 different parts of plants. Soon after the egg is inferted into 

 the leaf, a fmall tubercle begins to appear, which gradually 

 increafes in magnitude till the, animal is hatched, and 1i:as 

 pafTed through its diirerent transformations. Thefe tuber- 

 cles are known by the name of galls, and are very different 

 in their form, texture, colour, and fize. Galls of every 

 kind, however, derive their origin from the flings of infedls, 

 which generally belong to the clafs of flies. The female 

 fly, by means of her fting, makes incifions in the leaves or 

 branches of a tree, and in each incifion flie lays an egg. 

 This egg is at firft extremely minute ; but it foon acquires 



* Reaumur, vol. I2. page 412. edit. lamo. 



f Oeuvresdc Bonnet, vol. 4. page 28. edit, 8vo. 



O o 



