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wither, I placed frefh branches near the others, to which the ca-^ 

 terpillars remoA^ed themfelves. 



When thefe caterpillars came to their full growth, they prepared 

 to enclofe themfelves in a web fimilar to the filk worm, with this 

 difference, that at one extremity of their web or cafe, there was a 

 fmall aperture. A rcprefentation of this web is given at fn;. 20. 

 Thefe animals, thus inclofed in their web, I put into a glafs tube, 

 together with feveral others of the fame kind which I had found on 

 the apple trees, placing the whole in a large glafs. After fome 

 time, I faw come out of the greatell part of thefe webs certain 

 white flying infeds, having their wings diverfified with black 

 fpots ; they were fome\vhat fmiilar to thofc flying animals found in 

 granaries, and proceeding from the Maggot, which mealmen, and 

 bakers likewife, call dc If^olf, and of which 1 have treated fully in 

 another place. I was deflrous of keeping thefe creatures alive till 

 1 fliould fee whether they would lay eggs, but they all died. 



I have eaufed a drawing to be made of this flying animal, as it 

 appeared to the naked eye, when come out of its web, and this is 

 to be feen at Jig. 2 1 . To have made a drawing of it from the mi- 

 crofcope, would have been too troublefome, by reafon of the mul- 

 titude of feathers with which, not only the wings, but the feet, the 

 horns, and the whole body were covered, and alfo by reafon of a 

 crooked organ on the fore part of its head ; the true form and make 

 of which I was not able to obferve with fufficient accuracy. 



Among thefe flying animals, I faw in the glafs two blackifl^ 

 Flies, which I conceived muft have been produced in this manner, 

 namely, that fome black Fly of the fame fpecies having laid its egg 

 upon oneof thofe caterpillars, the Maggot thence produced had fed 

 upon the caterpillar till it had acquired its full growth, and there- 

 upon was changed into a black Fly, inftead of the web producing 

 a white flying animal with black fpots. 



In one of the glafles, wherein I had inclofed the webs I have 

 raentionedj there iflucd from thofe webs not only the flying animtvlsr 



