THE BLIGHT-BEETLE. 
89 
followed by tlic immediate death of the part affected. This 
kind of blight, as it has been called, being oftenest confined 
to a single branch, or to the extremity of a branch, seems to 
be a local affection only. It ends with the death of the 
branch, down to a certain point, but does not extend below 
the seat of attack, and does not affect the health of other 
parts of the tree. In June, 1810, the lion. John Lowell, of 
Iioxbury, discovered a minute insect in one of the affected 
limbs of a pear-tree ; afterwards, he repeatedly detected the 
same insects in blasted limbs, and his discoveries have been 
confirmed by Mr. Henry Wheeler and the late Dr. Oliver 
Fiske, of Worcester, and by many other persons. Mr. Low- 
ell submitted the limb and the insect contained therein to 
the examination of Professor Peck, who gave an account 
and figure of the latter, in the fourth volume of the “ Massa- 
chusetts Agricultural Repository and Journal.” 
From this account, and from the subsequent communica- 
tion by Mr. Lowell, in the fifth volume of the “ New Eng- 
land Farmer,” it appears that the grub or larva of the insect 
eats its way inward through the alburnum or sap-wood into 
the hardest part of the wood, beginning at the root of a bud, 
behind which probably the egg was deposited, following the 
course of the eye of the bud towards the pith, around which 
it passes, and part of which it also consumes ; thus forming, 
after penetrating through the alburnum, a circular burrow 
or passage in the heart-wood, contiguous to the pith which 
it surrounds. By this means the central vessels, or those 
which convey the ascending sap, are divided, and the circula- 
tion is cut off. This takes place when the increasing heat of 
the atmosphere, producing a greater transpiration from the 
leaves, renders a large and continued flow of sap necessary 
to supply the evaporation. For the want of this, or from 
some other unexplained cause, the whole of the limb above 
the seat of the insect’s operations suddenly withers, and 
perishes during the intense heat of midsummer. The larva 
is changed to a pupa, and subsequently to a little beetle, in 
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