183 
' 
IMMERSION EXPERIMENT. 
I began an experiment August 4, 1894, to ascertain the length 
of time for which bugs of the first annual generation could endure 
complete immersion in water without perishing. A miscellaneous 
lot of bugs of all ages was collected from corn on the University 
Experiment Station grounds and brought to the insectary. Half 
a dozen, representing each of the various stages of development, 
were selected and placed in ordinary one-ounce glass bottles with 
wide mouth. Adults that had just emerged from the pupal stage 
were selected and left in the bottles for several hours—until they 
were fully hardened. Three bottles for each of the various stages 
were prepared for each separate immersion. A thin layer of cot¬ 
ton previously soaked in rain water was spread over the bottom of 
each bottle, which was then filled with rain water at a tempera¬ 
ture of 70° Fah. The cotton rising to the neck, the bugs could 
be kept entirely immersed for any definite time desired. 
The young, especially the pupae, sink more readily in water 
when entirely immersed than adults. I do not believe that adult 
chinch-bugs would be entirely immersed in water during an ordi¬ 
nary rainfall unless they were entrapped under rubbish or in 
cracks in the ground or on roots of some submerged plant. It is 
almost impossible to keep them under waier unless some mechan¬ 
ical device is arranged to hold them; while, on the other hand, 
pupse kept immersed for a few moments will rapidly sink to the 
bottom. This difference is owing, no doubt, to the air retained 
under the wings of an adult. The details of this experiment aie 
given in the following notes: 
No. 1. Five lots of young bugs just emerged from the eggs 
were immersed August 4, as described above. It is probable that 
they were of the second brood, although I am not certain on this 
point. This is, however, of little importance, since the hardiness 
of the young cannot vary much in the two generations. The first 
lot were immersed at 8:55 a. m. August 4, and were removed 
half an hour later and placed on a dry towel, where they re¬ 
mained four minutes and then crawled away. The second, third, 
and fourth lots were similarly immersed for one, two, and three 
hours respectively, and then placed on the towel. All but thiee 
bugs in the one-hour lot and all but seven in the two-hour lot 
revived in from five to ten minutes after removal from the water, 
while only four of those which were immersed three hours revived 
after lying on the towel for fifteen minutes. The fifth lot were im¬ 
mersed four hours, but were lost accidentally while being removed* 
The attention the other lot required at this time prevented the com¬ 
pletion of this experiment. From the above, however, it seems 
that newly-hatched chinch-bugs cannot withstand immersion much 
over two hours. 
No. 2. Five lots of the first molt were immersed in a similar 
manner the same day. The first three lots were kept under 
water two, three, and four hours. All those of the first lot revived 
in from eight to twelve minutss, aud the second lot were crawling 
about in from twelve to fifteen minutes; but six of the third lot 
