PARASITIC FUNGI. 
49 
With a view of learning whether or not there was any difference as regards 
susceptibility to the attack of Entomophthora between bugs In different stages 
■f development, a series of experiments was begun, as follows: 
Young plants of Setaria glauca were transplanted to a i>o\. and upon each 
plant was placed a dead bug covered with the fungus, and also healthy larvae; 
larva? just on the point of pupation : pupae just prior to reaching the adult stage, 
and fully developed adults, cadi stage being placed on separate plants, and each 
covered with a small inverted glass vial designated i>y lettering. As checks, 
another scries was prepared, like the first in every particular. The soil in 
the box was kept well moistened, and the plaids remained fresh. This experi- 
ment was made on August -. about the time when the attack outside began to 
diminish in Intensity. The following are the results of examinations on the 
dates indicated, the original experiments being indicated by capitals and the 
checks by small letters, thus — A-a, adult: B-b, young larva?; C-c, older larva?; 
D-d, pupa'. 
Date. 
A. 
Bealthy.. 
l dead .... 
All dead.. 
AH dead.. 
a. 
B. 
b. 
C. 
c. 
D. 
Am:. "> 
Auk- G 
Bealthy.. 
1 dead.'... 
3 dead.... 
All dead.. 
Healthy.. 
Healthy .. 
3 dead.... 
All dead.. 
Healthy.. 
Healthy .. 
1 dead 
All dead.. 
i dead 
1 dead 
3 dead .... 
All dead.. 
Healthv . 
Healthy . 
i dead ... l dead. 
3 dead ... 1 d.-.-id. 
tug. 16 
All dead. 
All dead. All dead. 
On the same day this experiment was begun a second was also commenced, 
like the first in every particular, except that the healthy hugs used in experi- 
mentation were exposed to fungus-infected individuals for only five hours and 
then placed under their 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 be communicated during 
a period of five hours' exposure. 
On August 7 a large number of healthy hugs were placed under glass, with a 
Dumber 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 mois- 
ture as possible. August 10 the original experiment was divided and a portion 
of the healthy hugs 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 hugs had been con- 
tinually in dry quarters, not a single hug had died from Entomophthora. Not 
only this, but none of those which had heen removed after three days and placed 
in dry quarters had died, showing that the disease was not contracted and did 
not develop in healthy hugs, though kept exposed in a dry atmosphere for fifteen 
days, nor could it he 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 live days after 
being confined with the Entomophthora the healthy Iuilts 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 num- 
ber 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 con- 
26608— No. 69—07 M 4 
