131 
with earth. Water was poured into the pan outside of the cage, 
and kept standing there continuously to insure the saturation oc 
the earth and the air inside the cage. 
June 2, water stood in drops on the sides of the cage and on 
corn and grass within. June 4, no losses among the chinch-bugs. 
June 9, many of the bugs dead, but with no trace of fungous 
growth. June 13, adults now all dead, bat with no appearance of 
disease; young still in good condition; earth saturated and moist¬ 
ure standing in drops on plants and all over the inside of the 
breeding-cage. June 15, only a very few young bugs left alive, none 
having shown fungous disease at any time. Between this and 
July 3, those remaining died; and at the latter date, when the cage 
was overhauled, no growth of a fungous parasite had appeared on 
these specimens. 
The two following (Nos. 73 and 74) are successive field infection 
experiments conducted by Mr. Johnson near Odin, in Marion 
county, a district especially favorable for experimental work, each 
being followed up by repeated visits, from August 7 to October 6. 
No. 73. August 7, several hundred fungus-covered bugs from 
No. 68, were placed behind leaf sheaths and on the ground in a 
field of late corn on the farm of Mr. W. G. Ferguson, Sr., one 
mile north of Odin. The spot chosen was especially favorable to 
the growth of the white fungus, being along a dead furrow in a. 
low, damp place where the corn was much dwarfed and com¬ 
pletely covered with chinch-bugs which had come largely from 
an adjoining wheat field. No fungus-covered insects were seen 
here at the time. 
Every hill on the west end of the twenty-third row, counting 
from the south side, was treated with spores of muscardine for a 
distance of thirty paces. The tassels were cut, marking the east 
and west boundaries. Chinch-bugs both young and old, were very 
abundant; adults were copulating, and young just past the first 
moult reddened the stalks. 
This field was examined by Mr. Johnson September 5. Very 
heavy rain had fallen the day before, and the field was very 
muddy. No traces of disease were found, except a single fungus- 
covered insect behind a leaf. The corn was nearly destroyed by 
the chinch-bugs, and flat on the ground in many places, especially 
in that part of the field where the infection material had be* n 
distributed. Only five or six stalks of the hills treated remained 
standing. Stalks flat on the ground and not dead were literally 
covered with live bugs. Other parts of the field, where the corn 
was most vigorous, and where the bugs were least abundant on 
our former visit, were now overrun with the chinch-bug hosts; in. 
one place about two thirds of a pint were collected from two hills,, 
by jarring and shaking them over a cloth spread on the ground.. 
The insects were very active, and apparently in a healthy condi¬ 
tion. 
At this date (September 5) Mr. Johnson placed a second lot of 
infected bugs from experiment 68 in this field, where the condi¬ 
tions were especially favorable. The ground was very wet and 
