OF INSECTS, &C. 351 



the latter bearing no fruit, and their leaves being 

 eaten by the caterpillar, while the former have 

 borne fine clean fruit ever since. 



The trees, twenty-five in number, which I left 

 to nature, continued in a sickly state for three 

 years, neither bearing fruit nor putting forth 

 shoots. After the third year I headed them down, 

 scraping the stems and clearing of}' the insects ; 

 they are now recovered, having made as fine wood 

 as the others, and are in a healthy flourishing 

 state. 



Fig. 2. Plate IX. represents different states of 

 a kind of moth, whose caterpillar has for many 

 years done great mischief among Pear-trees on 

 walls. One wall in particular, in Kensington 

 gardens, was very much hurt every year, for 

 several years successively. 1 imagined that it 

 had been the effect of lightning, or a blight ; 

 till, on picking off the caterpillars, we found a 

 small sort in its case, sticking to the leaves, as 

 at a, (See the description of the Plate.) All the 

 first leaves were destroyed by the caterpillars : I 

 was, therefore, rejoiced that I had found out the 

 cause of their being so much injured every year, 

 being perforated in many places, and dropping 

 off very early. 



The Chermes. 



Chermes is a genus of insects belonging to the 

 order Hemiptera, and of which there are twenty- 



