THE GOLDSMITH BEETLE. 479 



of vegetation was considerably retarded. The dif- 

 ference in that of the hop was from sixty-four to 

 eighty per cent., while in others it was not more 

 than four. If this occurred when the wood was 

 soft, it caused a sudden stagnation of the sap in the 

 leaves, while the cells were distended with the cir- 

 culation. Their lesion, and the discharge of their 

 contents, can easily be accounted for in a district 

 where a plant had not been furnished with sufficient 

 carbon to properly strengthen its cell walls. Thus 

 it seems to result from lesion produced by weakness 

 of the cell wall from want of carbon, acted upon so 

 as to produce stagnation. The only remedy yet dis- 

 covered is immediate amputation of the part. The 

 prevalent idea that it is contagious, results from the 

 rapidity with which this poisonous sap conveys the 

 elements of decay, when the circulation is restored, 

 and it becomes mixed with healthy sap. 



2. Insects. (1) The attack of the Goldsmith Beetle 

 — Areoda lanigera. This appears about the middle 

 of May. It flies during the night, and clings to 

 the under surface of the leaf during the day. It 

 consumes the young leaves of the pear and those 

 of some forest trees. It is not usually sufficiently 

 prevalent to injure the tree. If it becomes unduly 

 multiplied, spread a sheet under the tree, and strike 

 the stem a smart, quick blow, when it falls, and can 

 be picked up and burnt. It is " nine-tenths of an inch 



