LETTER LIU. 



'To the same. 



I have sometimes known you make inquiries 

 about several kinds of insects, I shall here send 

 you an account of one sort which I little expected 

 to have found in this kingdom. I had often 

 observed that one particular part of a vine growing 

 on the walls of my house was covered in the 

 autumn with a black dust-like appearance, on 

 which the flies fed eagerly ; and that the shoots and leaves thus 

 affected did not thrive ; nor did the fruit ripen. To this substance 

 I applied my glasses ; but could not discover that it had anything 

 to do with animal life, as I at first expected : but, upon a closer 

 examination behind the larger boughs, we were surprised to find that 



