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were thus produced, namely, by the before-mentioned kind of 

 fl\, laying its eggs on the leaves of the oak, where, when the 

 young maggot is hatched, it bites or pierces the vellels of the leaf, 

 fo that the juices flow out, and are hardened into globules, fpread- 

 ing themfelves, at the fame time, in a circular form like veffels,. 

 and thus produce what is called the gall-nut, and which juices, while 

 hardening, do inclofe the maggot in the middle. 



This newly-formed gall-nut fupplies the animal with food, 

 for it eats away the fubftance of the nut by little and little, round 

 about itfelf, whence proceeds the cavity we find in the middle of 

 thefe galls, and which cavity grows larger, as the animal increafes 

 in fize. And it feems to me, that unlefs fome of the large vellels 

 in the leaves were injured or perforated by one of the maggots 

 I have defcribed, there could not be any gall-nut formed, for in 

 every nut which I opened, I conftantly found a maggot (though 

 in an hundred fuch nuts, I found but two which contained more 

 than one) and this, though one gall-nut was fixty times the fize 

 of another, 



It is however to be noted, that the wounding or biting the 

 large veflels in the leaves, does not conftantly produce a gall- 

 nut ; for this is only formed, where a fufficient quantity of the 

 juices ifl'ues from the opened veflels ; to this alfo, the heat contri- 

 butes much, by condenfmg or thickening the juice ; and hereupon 

 it is my opinion, that where thefe veflels are opened in the morn- 

 ing, galls will more eafily be formed than when it happens in the 

 evening , for I law on thofe leaves on which were gall-nuts, and 

 alfo on thofe where none were to be feen, the leaves and veflels 

 much eaten into, and the veflels pierced through, and yet, not the 

 leaft appearance of the formation of a nut on the place. Farther, 

 I concluded, that many of thefe maggots get their fulienance 

 from the leaves without piercing the large veflels, for in many 

 places I faw the leaves eaten av/ay and in holes. 



In further profecuting my inquiries on this fubje61;, I found 



