PRACTICAL PAPERS—COLORADO POTATO BUG. 329 
bug is originally an Alpine species, its native home being the 
canons (kanyons) of the Rocky Mountains, and it therefore 
thrives best and spreads fastest in the more northerly regions, 
such as Nebraska, Iowa, Minnesota, Wisconsin and North Illi¬ 
nois; while in south Illinois, Missouri and Kansas it neither 
thrives so well nor spreads so rapidly. 
The question whether the true Colorado potato bug has ex¬ 
isted for an indefinitely long time in the country that lies to 
the east of the Mississippi river, or w 7 hether it is not the bogus 
Colorado potato bug that has there been mistaken for it, while 
the true Colorado bug has in reality emigrated into that coun¬ 
try from the Rocky Mountain region within the last four or 
five years, may seem to some of merety theoretical interest. It 
is, how r ever, of great importance. On the first supposition it is 
not probable that this bitter enemy of the potato will travel 
onwards towards the Atlantic; on the second supposition it 
will most likely invade Ohio within a year or two, spread like a 
devouring flame through the great potato-growing state of Mich¬ 
igan, and finally pass eastwards into Pennsylvania, New York, 
and New England. We make no apology, therefore, to our 
* 
readers for presenting them with the complete history of these 
two insects, copious illustrated by figures, and for pointing out 
the minute but invariable character which distinguish them, 
both in the larva and in the perfect state. This is the first time 
that the larva of the bogus Colorado potato bug has ever been 
figured and scientifically described. 
THE TRUE AND THE BOGUS COLORADO POTATO BUG. 
Figure 44 b , b , b , gives a view of the larva of the true 
Colorado potato bug, in various positions and stages of its 
existence; Figure 45 b ) b , of that of the bogus Colorado 
potato bug. It will be seen at once that the head of the 
former is black, that the first joint behind the head is pale 
edged with black behind only, that there is a double row of 
black spots along the side of the body, and that the legs are 
black. In the other larva (Fig. 45 b : ) on the contrary, the 
