76 INSECTS INJURIOUS TO VEGETATION. 



not enable me to determine with certainty to which of the modern 

 genera they are to be referred. The minuteness of the insect, 

 thB difficuky attending the discovery of the precise seat of its 

 operations before it has left the tree, and the small size of the 

 aperture through which it makes its escape from the limb, are 

 probably the reasons why it has eluded the researches of those 

 persons who disbelieve in its existence as the cause of the blasting 

 of the limbs of the pear-tree. It is to be sought for at or near the 

 lowest part of the diseased limbs, and in the immediate vicinity of 

 the buds situated about that part. The remedy, suggested by 

 Mr. Lowell and Professor Peck, to prevent other limbs and trees 

 from being subsequently attacked in the same way, consists in 

 cutting off the blasted limb helow the seat of injury, and burning it 

 before the perfect insect has made its escape. It will therefore be 

 necessary, carefully to 'examine our pear-trees daily, during the 

 month of June, and watch for the first indication of disease, or the 

 remedy may be applied too late to prevent the dispersion of the 

 insects among other trees. 



There are some other beetles, much like the preceding in form, 

 whose grubs bore into the solid wood of trees. They were for- 

 merly included among the cylindrical bark-beetles, but have been 

 separated from them recently, and now form the family Bostri- 

 CHiD^, or Bostrichians. Some of these beetles are of large size, 

 measuring more than an inch in length, and, in the tropical regions 

 where they are found, must prove very injurious to the trees they 

 inhabit. The body in these beetles is hard and cylindrical, and 

 generally of a black color. The thorax is bulging before, and the 

 head is sunk and almost concealed under the projecting forepart of 

 it. The antennse are of moderate length, and end with three large 

 joints, which are saw-toothed internally. The larvse are mostly 

 wood-eaters, and are whitish fleshy grubs, wrinkled on the back, 

 furnished with six legs, and resemble in form the grubs of some of 

 the small Scarabsians. The shagbark or walnut tree is sometimes 

 infested by the grubs of the red-shouldered A pate, or ^ipate hasil- 

 laris of Say, an insect of this family. The grubs bore diametri- 

 cally through the trunks of the walnut to the very heart, and un- 

 dergo their transformations in the bottom of their burrows. Sev- 

 eral trees have fallen under my observation which have been 



