+ 
beetle appears to have been first associated with injury to potato in 
1865. Forty-five years prior to that time it had been recognized as 
feeding on the sand bur, or beaked nightshade (Solanum rostratum 
Dunal.). a related solanaceous plant peculiar to the Rocky Mountain 
region. The beetle was described in 1824 by Thomas Say. With 
the advance of civilization westward and the cultivation of potato in 
the vicinity of its native home, the insect acquired the habit of feed- 
ing upon this more succulent plant, and about 1859 it had spread to 
the east as far as Nebraska. Two years afterwards it reached Kansas, 
and later Iowa, which it traversed in three or four years; so that by 
1864 or 1865 it had crossed the Mississippi River and invaded the 
western borders of Illinois. In its spread through Illinois it was de- 
scribed by Walsh as marching through that State “in many separate 
columns, just as Sherman marched to the sea; the southern columns of 
the grand army lagged far behind the northern columns.” By 1869 
it had found its way to Ohio, appearing almost simultaneously in the 
northern and western portions. During all this time, beginning with 
the year 1861, the insect had done considerable injury, and by 1870 it 
had become exceedingly destructive in the North and Middle West, 
and was continuing its eastward march at an increasing rate. It 
had now reached the Province of Ontario. By 1872 its depreda- 
tions in the West had noticeably abated, owing to the effectiveness of 
natural enemies and to the increasing use of Paris green! _ Its prog- 
ress eastward, however, continued, the northern columns becoming 
established in Pennsylvania and New York, the southern ones reach- 
ing Kentucky. The next year it made its first appearance in the Dis- 
trict of Columbia and West Virginia, and in 1874 it had reached 
the Atlantic seaboard and was reported from Connecticut to Mary- 
land and Virginia. 
3y the centennial year (1876) the Colorado potato beetle had 
spread over an area composing more than a third of the United 
States, so that it occupied at that time more or less completely the 
States of Colorado, Nebraska, Kansas, Minnesota, Iowa, Missouri, 
Wisconsin, Illinois, Michigan, Indiana, Ohio, Kentucky, the New Eng- 
land States, New York, New Jersey, Pennsylvania, Delaware, Mary- 
land, Virginia, and West Virginia, and the District of Columbia, in 
none of which was it native except in the State first mentioned. At 
that time it occupied also portions of Wyoming and southern 
Dakota—where it was perhaps also native—and a considerable part 
of the more arable portions of eastern Canada. 
The farther spread of this insect, particularly southward, is of less 
interest and has, in many instances at least, been dependent more or 
less on the increased cultivation of the potato. The following addi- 
tional statements as to the insect’s progress are taken from data 
[Cir. 87] 
