200 INDIRECT INJURIES CAUSED BY INSECTS. 



cies common in this country, and producing the same 

 effect, often to the destruction of the crop, the caterpillar 

 of which feeds in the centre of our apples, thus occasion- 

 ing them to fall a . Even the young grafts, I am informed 

 by an intelligent friend b , are frequently destroyed, some- 

 times many hundreds in one night, in the nurseries about 

 London, by Curculio Vastator^ Marsh., (Otiorhynchus ? 

 picipes] one of the short-snouted weevils ; and the 

 foundation of canker in full-grown trees is often laid by 

 the larvae of Semasia Wceberana*. The sap too is often 

 injuriously drawn off by a minute Coccus, of which the 

 female has the exact shape of a muscle-shell (C. arborum 

 linearis, Geoffr.), and which Reaumur has accurately 

 described and figured d . This species so abounded in 

 1816 on an apple-tree in my garden, that the whole bark 

 was covered with it in every part ; and I have since been 

 informed by Joshua Haworth, jun. Esq. of Hull, that it 

 equally infests other trees in the neighbourhood. Even 

 the fruit of a golden pippin which he sent me were thickly 

 beset with it. But the greatest enemy of this tree, and 

 which has been known in this country only since the 

 year 1787, is the apple-aphis, called by some the Coccus, 

 and by others the American blight. This 'is a minute 

 insect, covered with a long cotton-like wool transpiring 

 from the pores of its body, which takes its station in the 

 chinks and rugosities of the bark, where it increases 

 abundantly, and by constantly drawing off the sap causes 

 ultimately the destruction of the tree. Whence this 

 pest was first introduced is not certainly known. Sir 



* Reaum. ii. 499. h Mr. Scales. 



c See Observations on this Insect in the 2nd volume of the Hor- 

 ticultural Society s Transactions, p. 25. By W. Spence. 

 " Reaum. iv. 69. t. 5. /. 6, 7. 



