THE BLIGHT-BEETLE. 89 



followed hj tlie immediate death of the part aflFected. 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 Avith 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, 181G, the Hon. John Lowell, of 

 Roxburj, 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 jNIr. Henry AVheeler and the late Dr. Oliver 

 Fiske, of Worcester, and by many other persons. j\Ir. 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 " jNIassa- 

 chusetts Agricultiaral Repository and Journal." 



From this account, and from the subsequent communica- 

 tion bv i\Ir. Lowell, in the fifth volume of the " New Eno;- 

 land Farmer," it appears that the grul) or larva of the insect 

 eats its way inward through the alburnum or sap-wood into 

 the hardest part of the Avood, beginning at the root of a l)ud, 

 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 burroAv 

 or passage in the heart-Avood, contiguous to the pith Avliich 

 it svuTounds. By this means the central vessels, or those 

 AAdiich couA'ey the ascending sap, are diAaded, and the circula- 

 tion is cut ofi". This takes place Avhen the increasing heat of 

 the atmosphere, producing a greater transpiration from the 

 leaves, renders a large and continued floAv of sap necessary 

 to supply the CA^aporation. For the Avant of this, or from 

 some other unexplained cause, the Avhole of the limb aboA^e 

 the seat of the insect's oj^erations suddenly Avithers, and 

 })enshes during the intense heat of midsunnner. Tlie lavAa 

 is changed to a pupa, and subsequently to a little beetle, in 

 12 



