APHIS. 183 



regard to blights: the one that the insects which 

 cause them are brought from a distano - rerly 



Is; the other that they attach tL 

 none br. Neither of T 



opinions, as far as I have observed, is founded in 



I am induced from the numerous ob^ 

 tions I have made on insects for a series of years, 

 (in pursuing the cultivation of plants) to consider 

 Aphis as by far the most general cause of the 

 diseases distinguished by the name of Blights. 

 Other insects it is true, more especially the larvae 

 of some of the Lepidoptera, as those of the Pha- 

 IcencE tortrice-s, disfigure and do infinite mischief to 

 plants by rolling and curling up the leaves; but 

 these for the most part confine themselves to 

 certain trees and plants. Their ravages are also 

 of shorter duration, being confined to the growth 

 of one brood, and they are also .ral. It 



would be no difficult matter for me to fill a volume 

 with observations to which I have been an 

 w itness of the injuries which plants sustain from 

 insects; but that would be foreign to my present 

 purpose, which is to shew that the Aphis is the 

 grand cause of these diseases, and to place the 

 modus operandi or manner in which they effect 

 this business in its true light." 



" We are fully aware that certain gregarious 

 insects may at particular times rise up in the air, 

 and if small and light, be impelled by any wind 

 that mav chance to blow at the time; and on this 



V 



principle we account for that shower of Aphides 

 described bv Mr. White to have fallen at Selborne. 



