812 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 
or the attacks of some fungus, would better account for a destruction so 
widespread and apparently sadden. 
Daring tin- last half of the summer of 1881 and subsequent summers, 
spent in Maine, I was enabled to make :» mure careful examination into 
tin' causes of the disease, and think that without much doubt it was 
wholly due to the attacks of the caterpillar above mentioned. 
About the middle of July I went from Brunswick, Me., to the White 
Mountains, and observed a good many dead spruces and firs in the woods 
on either side of the road from Gorham to the Halfway House upon 
Mount Washington. The dead spruces and firs were in nearly all cases, 
especially those which had evidently been cut down during the preced- 
ing winter (1880-81), riddled by the mines or burrows of the bark-borer 
(XyJoterus bivittatus). 
The spruces were also infested by the common longicorn borer, Mono- 
hammus confutor, the larva? being found to have bored the tree in all 
directions. 
Living hemlock trees, 15 to 20 inches in diameter, were infested by 
large unknown longicorn borers under the bark, while the bark itself 
was mined in all directions by Hadrotrymus, whose burrows were very 
abundant in logs cut down during the past winter near the Glen House, 
and in barks stripped from the logs ; and the mines also occurred in the 
bark of living trees. 
About the 1st 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 be infested with 
myriads of three common borers (Xyloterus bivittatus, Xyleborus calatus* 
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 tilled, 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 miniug 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 Tomici in all stages of development, their numbers 
being astounding. In two hours I took 1,000 specimens of Xyleborus 
e<elatus 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 a single year, several seasons, 
