No. 104.] 109 



In addition to the apple it attacks the pear, the plum and the 

 apricot. 



It was discovered about seventy years ago, infesting the twigs of 

 pear-trees by boring into them, and causing the sudden withering 

 and dying of the leaves, fruit and the twigs, about the middle of 

 summer. Hence it came to be named \kiQ, i)ear-hlight heetle. 



At the present time, the insect is known under two forms of at- 

 tack. The first, under which it was first discovered, is that in which 

 the larva, upon hatching from the egg deposited, upon the bark, 

 penetrates the sap-wood at the root of a bud, and following the 

 course of the eye of the bud toward the pith, burrows around it and 

 partiall}^ into it. By this means the ascent of the sap is arrested, 

 and the death of the twig beyond tliis point follows. 



The second mode of attack is that of the trunk, as stated in the 

 above communication. Dr. Fitch, has described the burrows occur- 

 ring in the trunk of an apple-tree of ten inches in diameter, as run- 

 ning in a straight line through the bark and with the wood three- 

 fourths of an inch, with three lateral galleries of the same size 

 traveling off from this at right angles upon one side, and one upon 

 the opposite side — these galleries, which were 0.06 of an inch in 

 diameter, running up and down parallel with the grain of the wood. 



In the piece of the apple trunk containing the beetle sent by Mr. 

 D., the burrow extends to its center, curving slightly downward (or 

 toward what is apparently its lower end), where it turns and runs 

 upward for a half inch, and also downward to an indetei-minable 

 extent, as its lower end extended into the portion not sent. 



From these two differing forms of attack, Dr. Fitch inferred that 

 there were two generations of this insect each year, the first one ma- 

 turing in the trunk, early in the season, because the new shoots at 

 the ends of the limbs are not sufliciently advanced at that time to 

 accommodate the insect. 



It seems more probable, to me, that the species is single brooded, 

 and that the summer attack of the twigs is by the larva, which there 

 matures and emerges as a beetle, while the burrows in the trunk 

 are made by the mature beetle for shelter (hibernation perhaps), and 

 for feeding purposes. 



The number in which these beetles were found in the trunks of 

 apple-trees of Mr. D. seemed to offer an excellent opportunity of learn- 

 ing more of the life-history of the insect. The locality, Annapolis, 

 Md., being rather remote for me to visit conveniently, I was desirous 

 that ample material might be sent me for study. From my omit- 

 ting to accompany my request with the intimation that I would will- 

 ingly pay express charges, the material needed has not been received, 

 and the opportunity has been lost for the present. 



For the attack on the twigs, cutting off and burning those affected 

 is the proper remedy. For that in the trunk, we are not prepared 

 to offer a preventive, until it may be known if the perforations are 

 made, as I suspect them to be, by the beetle from the outside, and 

 at what season of the year they are cut. 



