124 
dwarfed stalks of the remainder, gave to the whole neighborhood 
an aspect of desolation. In some places the bugs still "blackened 
the stalks but there was a general movement toward an adjacent 
meadow, in which considerable damage had already been done. 
Observations made at later visits did not disclose any fungus- 
covered insects on this farm, and we must therefore class this 
series of experiments, Nos. 63-67, as absolute failures. 
The four following (68-71) are parallel laboratory contagion ex¬ 
periments, conducted at Natural History Hall in large covered 
wooden boxes, each six feet long by three wide and six inches 
deep, supplied with a layer of dirt half an inch deep, freed from 
leaves and rubbish and thoroughly moistened, the bottom of each being 
finally covered with a layer of fresh green oats, or the stalks and 
leaves of corn, for food. Each box was supplied with fresh food 
and live insects as circumstances required, usually every second or 
third day. The period of operations extended from June 22 to 
September 20, during which time a sufficient quantity of infected 
insects was taken out to supply nearly two thousand applicants 
throughout Southern, Central, and Northern Illinois, as well as 
large quantities for use in our own experiments. 
No. 68. June 22, a part of the contents of 54 were transferred 
to this box, together with a large quantity of live chinch-bugs 
from the field. Everything was thoroughly moistened and the box 
closed by means of a tight-fitting cover, screwed down, the cracks 
being afterwards pasted up with narrow strips of paper. June 25, 
found no very considerable development of the fungus. Large 
numbers of bugs dead which showed no appeal ance of the in¬ 
fection. Ten of these crushed in water on a slide and examined 
microscopically contained no fungus mycelium. One lot taken 
from earth at this time showed no traces of the disease; while 
several others taken from corn leaves were everywhere penetrated 
with mycelial threads of some kind of fungus. Dead insects re¬ 
moved and placed on damp sand for further observation. Spoiled 
food removed, and fresh oats introduced. June 26, quite a num¬ 
ber of fungus-covered bugs picked out from food and from 
surface of dirt; fresh food supplied and more live insects. June 
27, box in bad condition; all the earth, food, and insects removed. 
Box cleaned and re-stocked with fresh dirt, food, and live insects. 
Soveral of the whitened bodies taken out were returned to the 
box. The old material, dirt, food, insects and all, scattered in 
wheat (experiment 61). June 28, food renewed and live chinch- 
bugs introduced. June 29 and 30, fresh food supplied. 
July 1, box in very bad condition; considerable mold on the 
dirt, and many bugs covered with Aspergillus. Comparatively few 
covered with Sporotrichum. All the material removed, box washed 
out with soap and water, thoroughly burned over by means of a 
Bunsen burner, and wet with alcohol and burned out the second 
time. The bottom covered with moist sand about half an inch 
deep, fresh food introduced, re-stocked with live insects, and in¬ 
fected with fungus-covered bugs collected by Mr. Marten from 
fields at Odin June 22, and at Shattuc June 23. July 2, no ap- 
