274 ATREATISEOF 



appearance, of moving to diftant places 

 for want of wings. 



Others fay, that thefe infects are either 

 hatched or brought up by eafterly winds : 

 and this opinion feems the moil probable, 

 for they generally increafe moft when the 

 wind continues in that quarter ; but I 

 think the weather being generally dry then, 

 is the greateft caufe of their appearance. 



I have feen them upon trees in due wxft 

 afpecls, and all others, in dry weather, 

 but I never faw them upon all trees alike, 

 even thofe that were planted againft the 

 fame wall, neither upon all the young 

 branches of one and the fame tree, but I 

 have generally obferved the honey-dews to 

 adhere the ciofeft to the weakeil: trees, or 

 to thofe fnoots which are the weakeft or 

 moft fpungy -, and wherever the honey- 

 dew caufed the leaves to curl, foon after 

 there were fmother-fiies on their under 

 parts. Undoubtedly all trees upon the 

 fame afpeft, and all the branches of one 

 tree, muft receive the fame outward caufe, 

 to be blighted, and one as much as an- 

 other ', by which it is plain, that the fepa- 

 rate parts of a tree, or feparate trees, are 



in 



