Bacterial Disease of the Squash-hug. 341 



PRIMARY INFECTION EXPERIMENTS. 



In order to refer all cultures and subsequent results to 

 a definite and unmistakable source, a few preliminary 

 infection experiments were begun, the results of which 

 were recorded in detail. It seems well, therefore, to 

 preface particulars concerning the culture and infec- 

 tion work reported in this paper with the following fun- 

 damental infection records: 



Experiment 1. — A box breeding-cage was stocked with 

 about two hundred squash-bugs, both nj-mphs and 

 adults, squash leaves being daily supplied as food, and 

 kept fresh by inserting the stems through the cork of a 

 small jar containing water. From the preliminary dis- 

 ease-cage several dead bugs were taken August 1, 

 the bodies torn apart, and the pieces scattered about 

 the earth and food leaves in the new breeding-cage. In 

 two days ten bugs were dead, and in five days a total 

 of sixty dead was i-eached. At this date a few of the 

 dead insects were again broken in pieces and scattered 

 about the cage, while the remainder were piled in a 

 corner. On the eighth day the mortality reached ninety, 

 and the following day added ten more. The death rate 

 was now much lessened, and from August 12 to August 

 15 only three deaths occurred. A few insects had been 

 removed for various purposes, and on the last-named 

 date the number of living bugs remainiog was between 

 eixtj' and seventy-five, while about one hundred and 

 fifteen deaths had occurred. 



Experiment 2. — As a check on the preceding, about fifty 

 squash-bugs of the same lot were put into a much smaller 

 breeding-cage on the same date, August 1, and kept sub- 

 ject to similar conditions, but without inoculation. The 

 first death was noted August 7, but the bod3' of the 

 dead insect was normal. This cage was observed until 

 August 17, with a record of but one additional death, 

 and this not attributable to the disease. 



From the record of these two experiments it will be 



