CHINCH BUG WEST OF MISSISSIPPI RIVER. 49 
these cages the living chinch bugs were placed and cheesecloth 
stretched over the top to prevent their escape. All of the cages were 
kept on a table in the office, which was heated day and night, and were 
kept well moistened to promote the rapid development of the fungus. 
The live chinch bugs which had been dusted with the spores of the 
fungus were then placed in these cages and the results compared with 
check cages into which were placed live chinch bugs not previously 
inoculated. Most of the bugs were provided with plenty of food. 
Some, however, were placed in a cage containing no food to see if the 
rate of mortality and appearance of the fungus were to any extent 
dependent upon the food supply. These experiments are here given, 
with a record of each cage and its check. 
Experiments with living chinch bugs. 
CAGES CONTAINING PLENTY OF FOOD. 













| | 
| Number 
: Number | Number Number upon which 
Cage bugs Treatment giv | of days of bugs visibl 
No 5 : elven experiment! which Mes ae 
used. continued. died. Canes 
| appeared. 
f03 25) | Inoculated!:----.- 2 : eek Ps eee 14 11 7 
62 ADU Oheckee a seca enacts EI Tae acre ees 14 0 0 
b 63 15 | After 14 days transferred from 62a to See soe 24 15 11 
163 18 | Taken from 62a and inoculated........--..-.-, 24 17 7 
80 9 | Taken from 63a and placed in cage free froni® | 24 0 | 0 
fungus. 
82 PH NVEMOCUWIALOMNs 22 bocce eo ee ie Poe yee see one 22 18 4 
83 333 |) (Glee) Set SS Se Aas. So eeT ee Taine ace ae 22 0 
90 Doula Oe ee neato sen tei e asemae wee ye eeaiee = 31 20 7 
89 BSN I Me cok ONCE ie Fs ecu eee eee see ees ers 31 4 0 
93 25 Be OO eeu tec eceeielaae cee ee aoe Se oasis See ete 35 20 1 
92 30 SAO onc Se ne = Soe Se RR Be ata fate 39 4 0 
108 Heat AO oar meas adios Sasjlasicec a oe seeeee seam ce 30 17 11 
108a Des || eae Oe Se tenia ae ae Nee ets inet ita secs ans 30 5 0 
CAGES CONTAINING NO FOOD. 
F : | 
120 SOU INO Cte eee oe ete ese]. + Jeeteh as 18 27 | 21 
122 25 GHW tay ens cen ene cine: Sea des kia cmin ees Sok ald 18 5 0 


The fungus always appeared about the third day after the death of 
the chinch bug, and in no case did it appear sooner than six days after 
inoculation, the bugs gradually dying and some remaining alive 35 
days. Living bugs removed from cage 63, where the bugs were dying 
and fungus developing, did not die when removed to another cage 
away from all infection, even though the moisture conditions were 
about the same. However, all of those remaining in cage 63 died 
and afterwards became covered with the fungus. This indicates that 
the rate of mortality can be checked if the bugs are removed from the 
presence of the fungus. 
As between the inoculation and check cages there was a marked 
difference observed in the rate of mortality, for which no cause other 
than Sporotrichum seemed to be responsible, as the death rate was 
always greatest in the inoculated cages. The greatest mortality and 
