55 
year in places where they were the year before the most abun¬ 
dant, and an increase in places where they were then less numer¬ 
ous. This territorial propagation outward from a center of first 
excess, accompanied by a diminution in numbers in the principal 
area of origin, has been fully described above; and a similar prop¬ 
agation from districts where the crop most preferred and first in¬ 
fested (wheat) is most abundant, to adjacent districts where the 
leading crops are those freely fed upon but less preferred, (oats, 
grass, etc.), is also highly probable, but less easily demonstrated. 
In both cases the diminution in numbers is doubtless largely due 
to the direct and indirect consequences of over-crowding,—a condi¬ 
tion which always arouses or intensifies the action of the natural 
checks on excessive increase. 
Further comparison of the crop areas of 1886 with the injuries 
of 1887 shows that a very decided diminution of the corn area 
has had little or no effect to diminish the loss to small grain the 
following year. 
From the above we learn that the proper procedure respecting 
the grass and the cereal crops in the presence of a chinch-bug 
uprising is the prompt and early abandonment of wheat or a de¬ 
cided limitation of its area, to be followed presently, if the attack 
continues, by a diminution of the oats acreage also, and the sow¬ 
ing of clover, whenever practicable, instead of the grass forage 
plants. We also find that these measures must be taken early or 
not at all, since if too long postponed they may easily do more 
harm than good. 
An analysis of the published opinions of economic entomologists 
shows a general and rather indiscriminate dependence on the 
abandonment of wheat culture as a defence against the chinch 
bug, this opinion being more positive, however, among the older 
entomologists than among those who have studied the question 
recently. It is a pleasure to find that the foregoing elaborate 
study necessitates little amendment of the recent statements and 
recommendations made from this office. A similar indiscriminate, 
but not unanimous, opinion as to the advantage of the abandon¬ 
ment of wheat appears in the statements of 200 agricultural cor¬ 
respondents of the office, 87 per cent, of the replies to an inquiry 
touching this matter being in the affirmative. 
From the miscellaneous experiments here reported, it appears 
that the worst infested fields of small grain may be sustained 
under a chinch bug attack by heavy fertilization, if the land be 
originally in good condition; and that, in general, the damage done 
will vary inversely to the fertility of the soil and the support 
given by fertilizers to the crop attacked. The best fertilizers for 
this purpose on the wheat lands of the central part of Southern 
Illinois, seem to be, first, barn-yard manure, and, second, the 
' phosphates and nitrates combined. 
The kerosene emulsion, whose deadly effect on the chinch bug 
was first shown by me in 1882, has repeatedly proven a very valu¬ 
able agent in the hands of farmers when applied in tho field for 
