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IX. On an Insect which is occasionally very injurious to Fruit- 

 trees. In a Letter to the Right Hon. Sir Joseph Banks, 

 Bart.K.B.P.R.S.fyc. % William Spence, Esq. F.L.S. 



Read June 2, 1812. 



My dear Sir, 



A s you give me reason to think that the few facts which I 

 have observed relative to the history of Tortrix Wceberana, 

 the larva of which is very injurious to the fruit-trees in my 

 garden, will be acceptable to the Horticultural Society, I 

 beg leave, through you, to lay them before that valuable 

 Institution, accompanied by a popular description of the 

 insect in its different states. 



My attention was first attracted to it some years ago, by 

 observing small masses of saw-dust-like excrement, the 

 usual indication of the presence of larvae, protruding from 

 the edges of the cankered parts of a very diseased sum- 

 mer Apple-tree, of the name of which I am ignorant. On 

 cutting off a portion of the wood, I found many small white 

 larvae inhabiting cavities, which they had excavated between 

 the bark and alburnum, and sometimes wholly in the latter, 

 upon which they seemed to feed. These larvae were of dif- 

 ferent sizes, and amongst them were several chrysales, which 

 being detached, and placed under a glass, produced in a few 

 days the Tortrix Wceberana, a small moth very abundant in 

 the garden, and thus proved to be the parent of the larvae. 



VOL. II. E 



