52 
3.87 inches less than the first. When divided into septenary peri¬ 
ods, the average of the last is 5.55 inches less than that of the 
first. 
So far, then, as the rain records of our State show, there has 
been a decided decrease. I may remark here, that this conclusion 
differs from that arrived at by Dr. Draper from his examination of 
the rain records of New York City and vicinity; but the rainfall in 
New York City, or at any point on the sea-coast, or larger lakes, can¬ 
not form a fair test in reference to the increase or decrease of rain¬ 
fall in the interior part of the country. The only records by which 
this question can be properly tested are those of the interior of the 
country, where there can be an increase or decrease of forests, and 
where the effects of cultivation of the soil, the draining of swamps, 
ponds, etc., can be felt. 
By forming curves of the seasons, Spring, Summer, Autumn and 
Winter, similar to that given in Figure 2, we gain a few additional 
facts in reference to the chief points now under consideration. 
According to the theory advanced, and the rain and temperature 
curves of our figure, the year 1867 ought to have been a Chinch- 
bug year, but was not. The curves of the seasons for this year, 
being all low, would seem also to favor the advent of these 
pests. If we go back, to 1866, we find that the Summer and 
Autumn of this year were above the average, which probably 
accounts for the non-appearance of these pests in 1867. The years 
1871 and 1874 were marked Chinch-bug years, and we find that the 
Spring rainfall of these years was very light, and that the Summer 
and Autumn rainfall of the years previous (1870 and 1873), espe¬ 
cially the latter, was very small. These facts accord precisely with 
the theory advanced, and what all who have had any experience 
with these pests would expect. As the curves have not been drawn 
to agree with the theory, or the theory adopted to correspond with 
the curves, but each formed independently of the other, this agree¬ 
ment tends to strengthen our faith in the meteorological records 
fropi which the curves were drawn. 
It is proper for me to call attention here to what appears to be 
an error, that has obtained a place in Entomological, Agricultural 
and Statistical literature, and seems to have been, until I entered 
upon a thorough investigation of the subject, generally accepted as 
correct. 
I allude to the estimated loss on the wheat crop by the Chinch- 
bug in 1864, made by Dr. Shimer, and that on the crop of 1871, 
made by Dr. LeBaron. 
Dr. Shimer says, in his article on the subject, that “this insect 
attained the maximum of its development in the Summer of 1864, 
in the extensive wheat and corn fields of the valley of the Missis¬ 
sippi, and in that single year three-fourths of the wheat and one- 
half of the corn crop was destroyed throughout many extensive dis¬ 
tricts, comprising almost the entire Northwest, with an estimated 
loss of more than $100,000,000 in the currency that then pre¬ 
vailed.” 
By reference to Die statistics for the years 1863, 1864 and 1865, 
as given in the Reports of the Agricultural Department, we find 
that the yield per acre of corn and wheat in Indiana, Illinois, Mis¬ 
souri, Iowa and Wisconsin was as follows: 
