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"bark and standing like beads of amber all over the trunk and limbs. Each of 
these drops show where one of these minute beetles has perforated the bark. On 
examination many will be found still in their tiny burrows beneath the bark, 
usually in groups of three of four, and others will be found boriug their way 
through the bark to deposit eggs. 
Xyleborus Xylographus is a considerably larger species, measuring between 
two-sixteenths and three-sixteenths of an inch in length and about one-sixteenth of 
an inch in diameter. The thorax is nearly as long as the body, and is bluntly 
rounded in front, the head being deeply sunken in it and almost hidden. The end 
of the body appears as if a piece had been gouged out, and the sloping tips of 
the elytra bear several small teeth and are bearded with hairs. The beetle varies 
in color from yellow to yellowish brown, and, from its habits, has very appro- 
priately been named the “ wood-engraving” bark-beetle. It is said by Fitch to 
be “the most common and probably the most pernicious of all the insects infest- 
ing the forests in the State of New York” because “it is liable to attack trees 
that are in full health and vigor, those that are young as well as old.”” The beetle 
bores through the bark, and then tunnels for some distance between the bark and 
the wood, lengthwise of the trunk or limb. Along the sides of this gallery the 
eggs (about fifty) are laid in notches, and, as soon as hatched, the young larve 
proceed to mine slender passages for themselves, working outward from the 
original one, and enlarging them as they proceed. Lach larva avoids, if possible 
eating into its neighbour’s burrow, and the tracks of some species of bark-beetles 
make very regular patterns indeed. The bark is thus so loosened from the 
wood that it dies and comes away in large pieces, enfeebling the tree and sub- 
jecting it to the attacks of large borers. 
Tomicus calligraphus, the “ elegant writing” bark: beetle, is slightly larger, 
but is very similar in appearance to the last species. It is of a chestnut brown 
color, and is sparsely clothed with yellowish hairs; the elytra being lined with 
coarse punctures. The burrow formed by the female in which to deposit her 
eggs is from six to twelve inches long, but more irregular than is that of the last 
species. The tracks of the larvee are more tortuous and larger, and the perfora- 
tions in the bark are also bigger. 
Tomicus pini, the pine bark-beetle, is smaller, being barely one-eighth of an 
inch long. It is probably the most abundant of all our pine bark-beetles, but as 
its ravages are said to be confined to old trees, it is not so serious a foe as the pre- 
ceding varieties. The tracks made by the larvee differ from those of other species, 
and look as if several eggs had been placed at the bottom of a hole bored in the 
bark, and the young had eaten outward in diverging directions. The burrows are 
about two inches long, and are eaten partly in the outer surface of the wood and 
partly in the bark. The beetle is dark brown, the tips of the elytra bearing each 
four teeth. 
Dendroctonus terebrans is the largest of our bark-beetles, measuring four- 
sixteenths to five-sixteenths of an inch in length and found in some abundance. The 
head is much larger, proportionately, than in the other species, and is plainly 
visible ; the thorax is shorter, and the elytra bluntly rounded at the tips, not ex- 
cavated, nor toothed. Its color is dark reddish or foxy. It perforates larger 
holes in the bark, and mines curving galleries in all directions, confined chiefly to 
the inner bark-layers, and only slightly grooving the surface of the wood. 
Hylurgops pinifex is a smaller and darker beetle, about three-sixteenths of 
an inch, or slightly more, in length, and of a dark reddish brown color; very 
abundant about lumber yards and pine groves. 
The last species which I shall mention resembles the foregoing, but is 
slightly slenderer and varies much in size ; being from two-sixteenths to four- 
