OF NATURAL HISTORY. 389 



the bodies of caterpillars. From thefe eggs proceed fmall mag- 

 gots, which gradually devour the vitals of the animal in which 

 they refide. When about to be transformed into chryfalids, 

 they pierce the flcln of the caterpillar, fpin their pods, and 

 remain on the empty fkin till they affume the form of flies, 

 and efcape into the air to perform the fame cruel office to 

 nnot4ier unfortunate reptile. Every perfon muil recollect to 

 have feen the colewort or cabbage caterpillar fi:uck upon old 

 Walls, or the windows of country cottages, totally covered 

 with thefe chryfalids, which have the form of fmall maggots, 

 and are of a fine yellow colour. One of the moft formi- 

 dable enemies of the caterpillar is a black worm, with fix 

 cruftaceous legs. It is as long, and thicker than an ordina- 

 nary fized caterpillar. In the fore part of the head it has 

 two curved pincers, w^ith which it quickly pierces the belly 

 of a caterpillar, and never quits the prey till it is entirely de- 

 voured. The largefb caterpillar is not fufficient to nourifh 

 this worm for a fingle day j for it daily kills and eats fever- 

 al of them. Thefe gluttonous worms, when gorged with 

 food, become inacSlive, and almoft motionlefs. When in this 

 fatiated condition, young worms of the fame fpecies attack 

 and devour them. Of all trees, the oak, perhaps, nourifhes 

 the greatefl number of different caterpillars, as well as of dif- 

 ferent infecfls. Amongft others, the oak is inhabited by a 

 large and beautiful beetle. This beetle frequents the oak, 

 probably becaufe that tree is inhabited by the greatefl num- 

 ber of caterpillars. It marches from branch to branch, and, 

 when difpofed for food, attacks and devours the firfl: cater- 

 pillar that comes in its way. 



The pucerons, vine-fretters, or plant-lice, are very injuri- 

 ous to trees and vegetables of almoft every kind. Their 

 fpecies are fo numerous, and all of them are endowed with 

 fuch a wonderful fertiUty, that we fhould expe(Sl to fee the 

 leaves, the branches, and the flems of every plant totally cov- 

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