39 
again occurred, the corn fields being now generally abandoned. The 
developmental "period was consequently about two months, reckon- 
ing from the time when the last eggs were laid until the transform- 
ation of the last of the brood was complete. Concerning their hi- 
bernation, no new facts were elicited, except that they could not be 
found in or about the fields where they had hatched. 
That the almost complete destruction or suppression of the spring 
brood was due to the prolonged and violent rains, there can be no 
reasonable doubt. The exact method in which rainy weather affects 
the bugs is, however, as yet undecided. That it cannot be simple 
submergence that destroys them is shown by a fact reported to me 
by Hon. Wm. McAdams. In his vicinity, in Jersey county, they 
were extremely abundant in the grain early in the spring, but were 
all apparently swept out of the country by a long and violent storm. 
Some days afterwards, when the water had subsided, he noticed in 
pulling over the drift wood in the river bottoms immense numbers 
of chinch-bugs among the rubbish, most of them still alive and 
crawling about. On the other hand, it seems unlikely that simple 
exposure to moisture has the effect attributed to rain, An experl- 
ment made at the laboratory bears upon this question, and will be 
worth reporting, although circumstances prevented its satisfactory 
‘completion. A number of hills infested by the bugs were success- 
fully transplanted to’ boxes and variously treated with water for ten 
days. Some selected examples were thoroughly drenched every day, 
both ground and stalks ;in other boxes only the ground was watered ; 
in still others the corn was sprinkled every day, but the round 
protected; and the remainder were left with only sufficient attention 
to keep the-corn alive. During the time for which these experiments 
were continued, no appreciable effect whatever was produced upon 
the bugs infesting the stalks. Those where the corn was watered 
were washed down upon the ground each time, but soon dried off 
and climbed up the stalk. At the end of this time the bugs under 
observation all commenced to disappear indiscriminately, without 
reference to the mode in which the corn had been treated, and the 
experiment was thus abruptly closed. Enough was learned, how- 
ever, to show that a succession of heavy daily showers for more 
than a week would have no appreciable effect upon these insects in 
that stage. The weather was warm and pleasant, and the condi- 
tions under which the experiments were carried on made it impossi- 
ble to saturate the air. Further light will be thrown on this ques- 
tion by the facts detailed under the succeeding section. 
NATURAL ENEMIES. 
Insects. 
To many the subject of the natural enemies of injurious insects 
may seem unimportant, since the prospect of utilizing them for an 
artificial regulation of the numbers of destructive species is some- 
what remote. But with regard to such insects as are still under 
investigation, no fact can be said to be unimportant, for the reason 
that the most insignificant data may, for all that we know to the 
contrary, lead finally to the most useful conclusions. Further, a 
- practical knowledge of the economy of the injurious species is not 
