THE CHINCH BUG. 
48 
ological conditions, the matter 1s here republished in full, the bulletin 
in which it was originally included being now out of print. 
These diseased bugs were placed under glass with living ones from the fields, 
the latter being provided with food and kept thus confined for fifty-three hours, 
when the major portion of them were placed on several hills of corn seriously 
infested by bugs, the remainder with the dried remains received from Professor 
Snow being scattered about over a small area of young wheat sown for experi- 
ment and also swarming with young chinch bugs. The hills of corn on which 
the bugs had been placed were isolated from others, equally badly infested, by 
narrow frames of boards placed on the ground and the upper edges covered with 
tar. This last precaution was taken in order to prevent communication with 
other hills, intended as checks on those used directly in the experiment. The 
area of young wheat over which infested bugs had been placed was not inclosed, 
but its limits carefully marked. Five days after, July 27, a single bug was 
found on one of the isolated hills of corn which had very evidently died from the 
effects of Hntomophthora, and by the 80th enough others were found to show 
that the fungus had fully established itself and the barriers about the isolated 
hills were removed. On August 2 dead bugs covered with Entomophthora were 
found in considerable numbers about hills of corn 25 feet from where the orig- 
inal colonies had been placed and also throughout and even 55 feet beyond the 
area of young wheat over which dead and affected bugs had been distributed. 
Daily observations were now made, but the progress of the disease seemed to 
come to a standstill. From the 5th of August up to the 9th it was almost im- 
possible to get sufficient material outside to enable me to carry on laboratory 
experiments. August 15 the spread of Entomophthora appeared to have taken 
on new life, and diseased bugs were becoming much more numerous. August 15 
found diseased bugs 172 feet from any place where they had been previously 
observed. August 20 diseased bugs were very abundant over all of the area 
where disease had been distributed, and two days later examples were found 
a quarter of a mile from the starting point of the disease. Immediately after 
this, however, another halt was observed, both in the intensity of attack and 
rapidity with which it spread, due either to the dry weather or to the fact that 
the bugs had now all reached the adult stage and had become diffused over the 
country, no longer congregating together. From either one or the other, or 
both of these causes, I lost track of the Entomophthora and was not able to again 
find it in the fields. It seems proper to state here that chinch bugs were not 
at any time excessively abundant. The greatest numbers were in the exact 
localities where the disease was first distributed, the congregating at these 
places being brought about by the close proximity to’a large number of small 
experimental plats of wheat, and when this was haryested the bugs collected en 
masse on the corn and young wheat. In connection with these facts, it is also 
interesting to note that from July 15 to August 31 there were ten days on which 
rain fell. The dates of these rains and the amount of precipitation is given 
below: 
ome | Precipi- Precipi- 
Date. tation. Date. tation. 
Inches. Inches. 
SY: WAT ace 2 Ske Oe eee eee (OO) |i UID Peace jot o tb oonssemeeserineasfsscos 0.78 
LQ 28 hsrehienon, cae eee een 1, 25 BOL h assess ecis Jae oe ee oe eee . 50 
DO so Bic AeA oteja< iia ee Oe yA) aN PANT Oey O mee ee eeepc ein einl<iniaiaicio telaie = laleeeeeee 3.36 
A EE Ee gee ee oS . 04 IS. Soa See eee sn eens .15 
DG eae dets Hoe nies Ue 2a Cee ee 218 VA sdaplegese thm dewsskt weincmssee meee . 02 
