35 
from Taylor’s Falls to the laboratory; they were divided into 
lots of about twenty each, and each lot was placed in a wire 
netting in which were pots of growing rape and grass. Six 
of these cages were sprinkled with six bouillon-cultures, and 
two cages were similarly prepared but not infected. The en- 
closed grasshoppers died gradually and as fast in one cage as 
in another, including the check-cages which were left unin- 
fected. None of those that died exhibited any signs of the 
disease. } 
On Aug. 7 thirty grasshoppers were placed in six cages 
and each set of five infected with one of the six species used 
in the previous instance. Hach grasshopper was rubbed along 
the spiracles with bacteria from a pure culture; a small por- 
tion was also placed in the mouth of each. The grasshoppers 
were Melanoplus femur-rubrum and Melanoplus bivittatus. They 
were placed in a cage containing growing rape. ‘Two cages 
were prepared similarly to these, but the grasshoppers con- 
tained were not infected. In the course of ten days they were 
all dead, having died with equal rapidity in all the cages, in- 
cluding the two check-cages, but none of them showed signs 
of disease. 
On Aug. 28 another box of dead and living grasshoppers 
came from Professor Gillette. A cage of wire-gauze was 
placed over a large piece of sod, and about fifty living and 
healthy grasshoppers introduced. Over this cage was placed 
another wire-gauze cage in which were the dead and living 
grasshoppers from Colorado. Water was now sprinkled daily 
over the upper cage from which it percolated through the 
dead bodies of the diseased hoppers upon the bodies and food 
of those underneath. This experiment was carried on in a 
cool shady place, where the best conditions for spreading the 
disease were approached as nearly as possible. The grass- 
hoppers in the lower cage died gradually, but exhibited no 
signs of disease, and showed no desire to cling to the wire 
netting, or to climb upon things as do those attacked by the 
disease. 
This inability to introduce a disease which was raging only 
afew hundred miles away among the same species of grass- 
hoppers that we have here, shows how truly dependant on 
climatic conditions are most of the diseases of insects as well 
