328 
WISCONSIN STATE AGRICULTURAL SOCIETY. 
the east has been about sixty-two miles. At the same rate of 
progression it will touch the Atlantic ocean in A. D. 1878. 
“But,” it will be asked, “how could any entomologists 
make the mistake of supposing that the Colorado potato bug 
had always existed in the northwestern states ?” The answer 
is, that, as was proved three years ago in the article already 
referred to, they indavertently confounded together two entire¬ 
ly distinct, but verv closely allied species, the bogus Colorado 
potato bug (Dorypliora juncta , Germar,) and the true Colora¬ 
do potato bug ( Dorypliora , 10 -lineata, Say.) The former of 
these has existed in Illinois from time immemorial; and, as 
we have recently ascertained, through the kindness of Mrs. 
H. C. Freeman, of Cobden, south Illinois, feeds there in the 
larva state upon theho. se-nettle (Solanum Carolinense , Linn.,) a 
wild species of potato, which grows, according to Dr. Asa Gray, 
“from Connecticut to Illinois and southward/’ The latter 
species, as has been already stated, only emigrated into Illinois 
in 1864, and in its native home, the Bocky Mountains, feeds 
naturally upon another wild species of potato, which is quite 
distinct from the hcrse-nettle, and is peculiar to the Bocky 
Mountain region. Again, the former species has never yet 
been known to attack the cultivated potato, and in all likeli¬ 
hood never will do so; for, as it has existed in Illinois for at 
least fourteen years and in Georgia for at least forty-four years, 
without ever having been known to attack this plant, which has 
been growing all that time in these two states, it is not at all 
probable that it will do so at any future time. The latter 
species, on the other hand, acquired this habit, as was shown 
before, in the region of the Bocky Mountains, when, for the 
first time the potato was introduced there, some twenty years 
ago; and from that region the potato-feeding race of this in¬ 
sect has since been spreading further and further every year 
towards the east. Filially the bogus Colorado potato bug is 
more peculiarly a southern species, occurring in the more 
southerly portion of Illinois, and in Missouri, Kentucky, Geor¬ 
gia, and probably Alabama, while the true Colorado potato 
