44 THE CHINCH BUG. 
were exposed to fungus-infected individuals for only five liours and then placed 
under tlieir respective glasses. As a result, on August 15, thirteen days after, none 
had died, thus strongly indicating that the Entomophthora did not exist generally 
in the fields, and that it could not he communicated during a period of five hours' 
exposure. 
On August 7 a large number of healthy hugs were placed under glass, with a 
number which had recently died from Entomophthora, the moisture in the vessel 
being absorbed by calcium chloride. A check experiment was also commenced, 
where the material and the conditions were the same, except the humidity of the 
atmosphere, care being taken to have the latter as nearly saturated with moisture 
as possible. August 10, the original experimeut was divided and a portion of the 
healthy bugs removed and placed in a damp environment, the remainder being kept 
under the original dry conditions. The results on August 22 were as follows: In 
the original experiment, where the healthy bugs had been continually in dry 
quarters, not a single bug had died from Entomophthora. Not only this, but none 
of those which had been removed after three days and placed in dry quarters had 
died, showing that the disease was not contracted and did not develop in healthy 
bugs, though kept exposed iu a dry atmosphere for fifteen days, nor could it be 
originated by placing, in a damp atmosphere, for twelve days, bugs which had been 
exposed to contagion for three days in dry quarters. The results with the check 
experiment were quite different. Within five days after being confined with 
the Entomophthora, the healthy bugs began to die from effects of the disease, and 
in three days more every one had died from the same cause, their bodies being 
covered with spores. 
Still another experiment was tried which consisted in confining a large number 
of healthy bugs with others diseased in a damp environment, and when the fungus 
had destroyed a portion the remainder were divided and a part removed to dry 
quarters. The result was that while those left in damp confinement continued to 
die, none of those inclosed in dry environment were destroyed. As the fungus had 
by this time become distributed over the experiment farm so that I could not tell 
with certainty whether material from the fields was in a perfectly healthy condition 
or not, no further experiments were made in this direction. 
From the foregoing it will be observed that the essential element in all of these 
experiments was an abundance of moisture, without which the Entomophthora 
could neither become established nor flourish after it had gained a footing. Again, 
the extent to which the disease will prove contagious will depend upon the number 
of bugs. Without great numbers massed together comparatively few would con- 
tract the disease. To sum up the matter, there is little hope for relief to the farmer 
from the influence of Entomophthora, except when chinch bugs are abundant and 
massed together in great numbers, and during a period of wet weather. I have suc- 
ceeded in getting the fungus established at two widely located points in Indiana, 
and do not consider it at all difficult to introduce in localities where chinch bugs 
are abundant, provided the weather is favorable. But if it is ever utilized by the 
farmer, which seems to me to be at present a matter of considerable doubt, it will 
only be after the pest has become very abundant, during the time between the first 
larval and adult stages and in a wet time. After the Entomophthora has been intro- 
duced into a certain field it will become diffused only in proportion as the bugs 
travel about and healthy bugs come in contact with spores from those which have 
died from the disease. This will not be very great until the pupal stage is reached. 
The larvae of chinch bugs seem to in some way understand that while molting 
they will be well nigh helpless, and hence hide themselves away in vast numbers in 
secluded places. Under such conditions the spores thrown from diseased bugs would 
reach a larger number of their fellows. I have found adults but recently molted 
affected by the Entomophthora. After the bugs acquire wings and scatter them- 
selves over the country, the liability to contagion will be again reduced, unless in 
case of very severe invasions, where, from force of numbers, congregating on or about 
food plants becomes a necessity. Hence, the introduction of the fungus among 
