DESTRUCTION OF SPRUCE FORESTS. 813 
mostly spent in Maine, demonstrated satisfactorily to my own mind that 
large, healthy firs, a foot in diameter, may be killed by the attacks of 
longicorn borers (Monohammus dentatus), assisted by the smaller and far 
more numerous bark-borers, and aided, perhaps, by caterpillars, with 
the final assistance of the common longicorn, Rhagium lineatum. Several 
living firs with only the lower branches dead were observed with the 
bark perforated with the holes made by the common longicorn pine-borer 
(see p. 685) and a Buprestid borer, while the boughs were tenanted by 
bark-beetles and their young. Fir trees along the road to Harpswell 
from Brunswick were also observed to be perforated in the same manner; 
and if a dozen longicorn borers can not only injure but kill outright 
large, healthy sugar maples, as has been observed in Brunswick, Me. 
(see p. 374), there is no reason why firs from 6 inches to 1 foot in dia- 
meter should not perish from a similar cause ; or if multitudes of small 
timber beetles or bark-borers girdle the tree from top to bottom with 
their mines, we do not see why this is not an efficient cause of rapid decay 
and death. 
A. G. Tenney, esq., has kindly handed us the following extract from 
the Home Farm, for July 14, 1881, published at Augusta, Me. : 
Some time ago two or three articles appeared in our journal concerning the injury 
to the spruce timber in the northern portions of our State, caused by a minute little 
insect about whose history little seems to be known. Since then we have received 
much information concerning them from a most intelligent gentleman resident in 
northern Somerset, who has been extensively engaged in lumbering for many years, 
and who has visited the spruce forests summer and winter, and observed the working 
of this very destructive insect. 
The gentleman informs us that the first appearance of the insect was in 1874, and 
he has reason to believe it is now much on the increase, as he thinks on some town- 
ships there are now thirty dead trees from this cause, where two years ago, on adjoin- 
ing townships, there was but one. The insect appears about the first of June, and on 
landings and jambs of spruce; the air is full of them. They are about as large as a 
black fly, and are of a brownish, or dark snuff-color, the head half the size or length 
of the body. They are very tenacious of life, being hard and horny, and it is almost 
impossible to crush one between the thumb and finger. They are seen for about two 
or three weeks, during which time the logs and standing trees in the wood are bored 
full of holes about the size of a timothy straw, in which the eggs are laid, the larvae 
of which appear the next summer. In felling trees in winter, thousands of these 
grubs drop out, from one-sixth to one-eighth of an inch long. The chickadees are 
very fond of them, and may constantly be seen following the lumbermen and picking 
up their food. If the spruce are cut the first year they are attacked, they make very 
good lumber, but the second year, or after the sap-wood has turned black, they are 
quite worthless, unless the tree is 2£ feet through, in which case the heart-wood 
is worth something for lumber, after the sap-wood is dead. The rapidity with 
which the wood of standing trees that have been punctured by these insects decays 
is noticeable from the statement that in autumn, when parties are exploring, 
the blazing of an apparently sound tree with the axe reveals the fact that the sap- 
wood is thoroughly gone. 
We have previously stated that Dr. Franklin B. Hough, the United States Commis- 
sioner of Forestry, visited this State last autumn and made an exploration of our 
northern forests, for the purpose of gathering information as to the extent of the 
ravages of this insect. In a letter to us, under date of May 6, 1881, he writes : 
" I am well informed as to the extent of damages being done to the spruce timber in 
