THE BOSTRICHIANS. 
91 
externally, and end with a short hook ; and the joints of 
the feet are slender and entire. This insect cannot be 
retained in the genus Scolytus, as defined by modern nat- 
uralists, but is to be placed in the genus Tumicus. The 
minuteness of the insect, the difficulty attending the discov- 
ery 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 below 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 formerly included among the cylindrical bark-beetles, 
but have been separated from them recently, and now form 
the family Bostiiichidad, 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 fore 
part of it. The antennafe are of moderate length, and end 
with three large joints, which are saw-toothed internally. 
The larvae are mostly wood-eaters, and are whitish fleshy 
grubs, wrinkled on the back, furnished with six legs, and 
