49 
were rapidly multiplying, in a bug which had been confined with- 
out food in a bottle for five days. The specimen was sluggish, 
but could still walk. With a view to locating more exactly their 
principal seat in the body, I crushed the head, thorax and abdomen 
of another upon separate slides. Very few bacteria were found in 
the head. They were much more abundant in the thorax, but not 
nearly so common as in the abdomen, the fluids of which were lit- 
erally swarming with them. From this observation it seemed prob- 
able that they occurred chiefly in the alimentary canal. To satisfy 
‘myself more exactly upon this point, I dissected, on the 15th, a pupa 
from Champaign, which had been kept without food since the 9th. I 
separated the entire alimentary canal, with trifling injury, until I at- 
tempted to detach it from the body at the vent. As soon as the needles 
penetrated the rectum, I noticed the escape of an extremely viscid 
fluid, which formed a delicate film on the surface of the water in 
which the dissection was made. This fluid was seen by a power of about 
sixty diameters to contain numerous minute cell-like bodies, which un- 
der a high power appeared to be globular masses of bacteria. This 
viscid film so interfered with the needles and entangled the tissues 
that the posterior portion of the intestine was torn to fragments, 
including the Malpghian tubes, but the hard structures were removed 
from the slide, and the cell in which the dissection was made, to- 
gether with its contents, mounted for study. Upon pressure with 
the cover glass, globular masses of bacteria were seen escaping from 
the stomach, similar in all respects to those previously studied. 
Immense numbers of free specimens. occurred everywhere on the 
shde, but scarcely anything else. 
On the 16th of August, in a field of corn near Normal, belonging 
to Mr. Conner, from which most of these specimens had been ob- 
tained, the chinch-bugs were evidently much less numerous than a 
fortnight previously, and they were also apparently greatly retarded in 
developmént. Not over ten per cent. had reached the pupa stage, 
and no adults had as yet appeared, while in other fields not far 
distant, ninety per cent. were pup, and many were winged. In the 
former field several dead bugs were found behind the sheatlis of the 
corn of all ages and sizes, but the mortality had evidently chiefly 
affected the older bugs. Several were collected, both dead and alive, 
and studied as usual. The fluids of one freshly dead were swarm- 
ing with bacteria, as were also those of another in the third stage, 
which was still alive, but had a swollen and unhealthy look. Taking 
it for granted that bacteria were most abundant in the alimentary 
canal, if not strictly confined to it, I next, on the same day, suc- 
cessfully dissected the pupa of a chinch-bug which had been for 
three days in confinement. I removed the alimentary canal as far 
as the Malpghian tubes, divided it in the middle, and placed the two 
parts upon different slides. Bacteria were present in both slides, 
but much the raost abundant in that containing the posterior part 
of the intestine. They were nearly or quite as abundant in the 
water in which the dissection had been made, a fact probably due 
to the rupture of the alimentary canal during dissection. These 
bacteria were evidently rapidly multiplying, occurring on both slides 
in zodglcea-like masses, and also in strings, of a length to simulate 
bacilli. On the 22d of August, the condition of things in the field 
