220 INSECTS INJURIOUS TO FOREST AND SHADE TREES. 
and in bark stripped from the logs; and the mines also occurred in the 
bark of living trees. 
About the Ist of August, during a visit to Peak’s Island, in Portland 
Harbor, large numbers, sometimes entire clumps or groups, of dead 
spruces were found to have been perforated by small bark-borers, not only 
the trunks but the larger and smaller branches, the beetles being still 
at work. Some of the spruces were partly killed, the upper branches 
retaining their leaves. 
At Brunswick, Me., the dead spruce trees were found to beinfested with 
myriads of three common borers (Xyloterus bivittatus, Xyleborus celatus, 
and Pityophthorus puberulus), the bark being mined in every direction, 
the beetles occurring in the larva and pupa, as well as adult or beetle 
condition. Some of the trees, only partly dead, had the bark of the 
trunk and branches filled, so to speak, with these mischievous borers, 
and the results of their united labors were equivalent to barking or 
girdling the tree not only in one spot, but the entire tree; the deadly 
nature of the attacks of such a host of bark-borers mining and feeding 
upon the inner bark and sap-wood, the most vital part of the tree, was 
sufficiently obvious. The stumps of firs and spruces, as well as of white 
pines, which had been cut down the previous November, were swarm- 
ing with these small Tomiciin all stages of development, their numbers 
being astounding. In two hours I took 1,000 specimens of Xyleborus 
celatus from one pine stump. 
But if there had been any doubt as to the nature of the disease which 
carried off the spruces at Brunswick, in the woods southeast of the col- 
lege grounds, in the course apparently of asingle year; my visit to Mere- 
point demonstrated satisfactorily to my own mind that large, healthy 
firs, a foot in diameter, may be killed by the attacks of longicorn borers 
(Monohammus confusor), assisted by the smaller and far more numerous 
bark-borers, 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. 152) and a 
Buprestid borer, while the boughs were tenanted by bark beetles and 
their young. Firtrees 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. 103), 
there is no reason why firs from six inches to one foot in diameter 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. 
We next visited Harpswell Neck, and found from our own observa- 
tion and by inquiry from others that a large proportion of the spruces 
and firs for a distanee of about ten miles have died within about four 
years. The pleasure of driving over this picturesque road, with its 
