208 THE NATUEAL HISTORY 



LETTER LIII. 



TO THE SAME. 



As 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 any thing 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 they were coated over 

 with husky shells, from whose sides proceeded a cotton-like 

 substance, surrounding a multitude of eggs. This curious and 

 uncommon production put me upon recollecting what I have 

 heard and read concerning the coccus vitis viiiifercB of Linnaeus, 

 which, in the south of Europe, infests many vines, and is an 

 horrid and loathsome pest. As soon as I had turned to the 

 accounts given of this insect, I saw at once that it swarmed on 

 my vine ; and did not appear to have been at all checked by the 

 preceding winter, which had been uncommonly severe. 



Not being then at all aware that it had any thing to do with 

 England, I was much inclined to think that it came fi-om Gibraltar 

 among the many boxes and packages of plants and birds which 

 I had formerly received from thence ; and especially as the vine 

 infested grew immediately under my study-window, where I 

 usually kept my specimens. True it is that I had received 

 nothing from thence for some years : but as insects, we know, 

 are conveyed from one country to another in a very unexpected 

 manner, and have a wonderful power of maintaining their exist- 

 ence till they fall into a nidus proper for their support and in- 

 crease, I cannot but suspect still that these cocci came to me 

 originally from Andalusia. Yet, all the while, candour obliges 

 me to confess that Mr. Lightfoot has written me word that he 

 once, and but once, saw these insects on a vine at Weymouth in 

 Dorsetshire ; which, it is here to be observed, is a sea-port town 

 to which the coccus might be conveyed by shipping. 



As many of my readers may possibly never have heard of this 



