

DISEASES 



Sect. XIV. 3. 2. 



parently injure the leaves ; as on the nut-trees, where perhaps the/ 



were not hatched from eggs, but might have come thither in th 



eir 



winged flate, and have then produced their innumerable viviparous 

 offspring ; as on the nut-trees above mentioned I could not difcern. 

 the eggs, from which they were hatched, and a few larger a'phifes. 



with wings appeared early in the 

 without wings. 



feafon amongft the 



fmaller onesv 



We may finally conjedure on this interefling fubjea, firft, that the 

 aphifes produced from eggs early in the fpring may have a larva or 

 caterpillar ftate, 



and that durino; that ftate 



they may feed on the 

 young leaves of peaches, ne6larines, plums, and cherries, and thus 

 cccafion them to curl and die. 2. That thofe, which are not from 



£)£> 



have no larva ftat 



d only pun6lure the larger chyle veffels 



of the you 



-1 



the pulmonary arteries 



f the leaves, which 



the vegetable fap-juice from the roots, 



d th 



us 



th 



hey 



fuck it up, and live on it, before it is converted into blood, as moth 



butterflies, and bees 

 other 



honey in their winged ftate, th 



o 



anther-duft, in th 



1 



a 



parts of vegetables,, as on their leaves, or 

 ftate ; and that thefe pun£lures are attended with no vifibl 



jury to the leaf. 3, That for a week or two about Midfummer, when 



the umbilical vefTels of the new buds convey the fap-juice to them, 



or to the refervoirs of nutrim.ent preparing for them, that the aphifes 

 by piercing thefe veffels, or the pulmonary arteries of the leaves, ac- 



quire fo 



a 



a quantity of 



faccharine material, th 



paffes 



through them almoft unchanged. 



falling on the leaves and ground 



beneath them, and produces what is called the honey-dew ; b 

 this happens only for a fhort 



feafo 



week or two ab 



Mid 



fummer, during the production of the new buds. And laftly, tha 

 the black powdery material on the upper furface of the leaves of th 



nut-trees 



ene 



and plum-trees, and of the fhrubs which grow b 



them, is an excrement from the aphifes, which hang on the unde 



furfaces of the leaves above them, like the black bitter powder m th 



nut 



h 



V 



