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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 17 
hickories in the grove. About a dozen trees had been attacked and 
killed during the summer (1913) and a number more were infested and 
partly killed. Several trees were also found which had been killed the 
preceding year. All of these killed trees were in one comer of the hickory 
grove and none of the trees showed the effect of the brood except in this 
one comer. No trees killed by the hickory bark beetle were found near 
Syracuse except in this one spot, although beetles were found in various 
places in felled trees and in broken branches. 
During the following year (1914) 111 hickories in the grove of less 
than four acres were killed—76 per cent of those still alive the preceding 
fall. That summer there w T as little tendency in the way of dispersal of 
the epidemic shown. It is true that perhaps a half dozen outlying 
pasture trees were attacked and killed but none of these were more than 
a hundred yards from the main group. This of course is easily ex¬ 
plained by the abundance of the proper host close at hand. 
In the summer of 1915 thirty of the thirty-five remaining hickories in 
the woodlot were killed by the beetles and in addition to these four trees 
some half mile away were also killed. These thirty-four hickories were 
the only ones found within a radius of one and a half miles to succumb 
this year. Had the injuries increased in the same proportion as in the 
preceding year, close to a thousand trees would have been killed in the 
summer of 1915. There can be no doubt that this year there was a very 
decided decrease in the injuries resulting in a partial control of the epi¬ 
demic. The explanation of this will be attempted later in this article. 
The later history of the epidemic will be given in general terms only 
because as the beetle spread farther and farther from the original focus of 
infestation it became increasingly difficult to keep specific data. In 
1916 the trees killed by the beetles in the area under observation were 
about as numerous as those of the preceding year but were distributed 
over a much wider area. Several trees in a wood lot a half mile south 
were attacked and killed and the tops of others were deadened. In an 
easterly and northerly direction the effects of the beetles were seen for 
about a mile and a half—the killed trees being mostly isolated hickories 
in pastures. In the several years following there was a progressive 
increase in the injury and a rapid spread, especially toward the north 
and east in the direction of the drive of the prevailing summer winds. 
By 1922 a great per cent of the hickories, especially pasture and roadside 
trees, had died at least as far east as Canastota (about 20miles). Appear¬ 
ances all point toward a progressive spread from the original focus at 
Syracuse. On account of the absence of specific data, however, it is not 
