28 
by many to be most destructive upon high land and in dry seasons, 
this seems to be due not to a greater number of worms in such sit¬ 
uations, but to the fact that the corn defends itself less easily by 
throwing out new roots. Certainly the years during which this pest 
is reported to have been especially destructive include about all the 
varieties of weather known to our climate, some being extremely 
dry and some extremely wet, some with the winter warm and open, 
and others extraordinarily cold. In short, we have as yet no know¬ 
ledge of any natural check upon the increase of this species except 
the necessary limit of its food supply. 
If the inquiry be made, why, in the absence of conspicuous 
natural checks upon its multiplication it has not long ago increased 
beyond all bounds, and destroyed the entire corn crop of the coun¬ 
try, the reply must be that there is a very effective artificial check 
upon this reproduction which has been unconsciously applied more 
or less generally, and that it is doubtless due to this that the pest 
has not increased more rapidly. The fact that the larva finds its 
food, as far as known, only in the corn-fields, and that eggs depos¬ 
ited elsewhere must all, or nearly all, fail of development, makes it 
necessary to the multiplication of this species that corn should be 
cultivated upon the same ground during successive years. Wherever 
rotation of crops has prevailed, consequently, it has met with seri¬ 
ous checks; but on the other hand, where, for any reason, 
continuous cropping of corn has been the rule, if has so increased 
as to threaten to occupy the entire country. This is especially 
noticeable in Stark county, in a region where the farmers have 
nearly abandoned the cultivation of wheat on account of the rav¬ 
ages of the chinch bug. Evidently as a consequence of this, the 
corn root-worm has become there more numerous and destructive 
than in any other region known to me. 
The future of this pest I believe- to depend almost entirely upon 
the farmers themselves. If the continuous cultivation of corn on 
the same ground is persisted in, unless something of which we have 
now no hint occurs to arrest the progress of the insect, it is little 
likely to confine itself to those fields in which it is undisturbed. 
Multiplying at a rapid rate, it must eventually overstock such 
ground, and, following the habit of insects generally, when its num¬ 
bers become excessive in any locality, it will probably, migrate in 
swarms to other regions less thoroughly occupied. It flies readily 
and actively, and might easily in this way become an almost uncon¬ 
trollable scourge. 
ARTIFICIAL REMEDIES. 
The inference from the foregoing to a frequent change of crops 
as a method of preventing the injuries of this insect, is too plain 
to require special comment. Not only our knowledge of the life 
history of the species, but also the experience of those suffering 
from its attacks, teach us that it will multiply indefinitely as long 
as ground infested by it continues to be cropped with corn, while a 
single season in grass or any small grain is sufficient to destroy 
those in the ground. No matter how thickly stocked with eggs the 
soil may be, we know of no reason to fear injury to any other crop 
