- 
sre eat EE I ot 
9 
three times the Rocky Mountain locusts ate up every green thing, and 
the drought often impoverished the farmer, but the insects named above 
were never responsible for more than local or partial damage to a 
crop. 
In other words, the normal healthfulness and balance which we have 
found in wild nature applies in the long run also to nature as influenced 
and partly controlled by man. It is the exception, not the rule, even 
with cultivated plants, that the damage is overwhelming and disastrous. 
In taking this broader view, one is not only impressed with, but con- 
vinced of, the stability, permanence, and repose of nature in the long 
run. The course of life is even, and the necessary antitoxin is fur- 
nished when needed. The balance may move a little up and down, the 
pendulum swing more or less widely from side to side, or the line of 
record may be a jagged one, but the average will be the normal right 
line which pictures simply nature’s method. 
Time does not offer to consider the means by which this balance is 
preserved, and many of the influences at work are obscure and beyond 
our easy finding out. Briefly noting some of the more evident influ- 
ences which operate to check undue increase of insects, disease plays 
a very important role; also any unfavorable climatic and seasonal con- 
dition, as note the result of the severe winter of 1893-99, and the effect 
of the occasional exceptional heat of the dry summers of California and 
southern Spain. Probably less important than the influences just men- 
tioned is the action of parasitic and natural enemies, and least impor- 
tant of all, the puny efforts of man. From the side of the host plants 
the chief influences are the weeding out of the nonresistant and weaker 
individuals and those growing under unsuitable conditions, and the 
development of increased vigor and power of resistance in the stronger 
ones. 
J have endeavored to show the self-curative and self-preservative 
action of living organisms in the long run. On a close inspection, 
especially of what concerns us personally and directly, many little ills 
appear, not, however, especially antagonistic to the workings of the 
general law indicated. These in our field of applied entomology are 
the local abundance from time to time of this or that injurious insect. 
There may be an outbreak in some limited section or in spots here and 
there of the army worm, the Hessian fly, the chinch bug, some species 
or other of locust, a scale insect, or some wood borer; or we may be 
temporarily annoyed by a plague of fleas or ants or flies. To correct 
such disturbances a knowledge of the habits, life histories, natural 
enemies and parasites, and of remedies is desirable; and in the control 
or prevention of such local annoyances intelligent effort finds an imme- 
diate practical and satisfactory outcome. In such work also the eco- 
nomic entomologist finds a legitimate and serviceable field for his 
activities. Nevertheless, the results gained, however locally valuable, 
affect little if any the normal course of events in the larger sense. 
