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weeds, and the grasses, but when it comes to warring upon the insect 
and fungoid enemies of his grains lie seems to lose heart. His reserve 
force is, or at least should be, in his superior knowledge ; but too often 
this virtue seems to be either sadly aborted or entirely wanting. He 
does not study ways to destroy or circumvent these enemies of his 
crops, but, on the whole, allows them to go their way, patiently 
taking what they leave and hoping for better luck another year. 
It is here that I wish to take up my subject and show how many of 
the insect foes may be either destroyed or prevented from inflicting 
serious injury. The field of applied entomology is not the science of 
killing insects, alone, but includes also the warding off of their attacks. 
For my own part I would reverse these terms, as it seems to me that 
the evasion of an attack is ordinarily the most important. I would 
put it in this way : Warding off the attacks of injurious species by 
preventing their breeding, and, in case this is not practical, destroying 
them either before or after the attack had begun. And I may be 
allowed to here make use of an oft-quoted adage, a An ounce of pre- 
vention is better than a pound of cure." 
There are upwards of 140 species or insects affecting these three grain 
crops, and maize alone has over 100 insect foes, a number of course dep- 
redating alike upon all three. Of these, such as infest the stored grain 
excepted, there are very few whose. attacks can not be far more easily 
warded off than remedied after they have begun. I know of no better 
insecticide than good farming. After eight years of study of the Hes- 
sian Fly (Ctcidomyia destructor), I am satisfied that four-fifths of its 
injuries may be prevented by a better system of agriculture. For years 
I have seen wheat grown on one side of a division fence without the 
loss of a bushel by attack of this pest, while on the other side the crop 
was almost invariably more or less injured. No effect of climate, mete- 
orological conditions, or natural enemies could have brought about such 
a contrast of results. The whole secret was in the management of the 
soil and the seeding. In fact, the question of success in evading the 
pest, in the one case, did not appear to be an entomological one at all; 
and I am fully convinced that the Hessian fly problem, so far as it relates 
to agriculture, throughout that portion of the country lying between 
the Alleghany Mountains and the Mississippi River, and between 
the Ohio River and the Great Lakes, may be considered practically 
solved. As applicable to this area, I have attempted to illustrate in 
Fig. 2, and also in Fig. 3, ideographically, the annual cycle of this insect, 
which can of course be only approximately correct for any single 
locality, there being a variation of nearly if not quite one month in the 
season of development between the northern and southern boundaries. 
It Avill be observed that there are four seasons in this cycle, two of 
activity and two of inactivity, or, we might term the latter resting sea- 
sons. Over this area the winter resting season is by far the longer, 
while the two active seasons are about equal. Toward the south I 
