Article XU.— On a Bacterial Disease of the Sqnash-Uig 

 {Anasa tristis DeG.). By B. M. Duggar. 



INTRODUCTORY. 



During July, 1895, while occupied as an Assistant in 

 the Illinois State Laboratory of Natural History, in 

 studying some fungous diseases of the chinch-bug I used 

 many squash-bugs {Anasa tristis DeG.) for expei'imental 

 purposes, their larger size making them convenient for 

 use in certain investigations for which the chinch-bug is 

 poorly adapted. These squash-bugs were kept in a lab- 

 oratory bi-eeding-cage, and daily supplied with fresh food 

 and a suitable amount of moisture. They were soon 

 observed to be dying in considerable numbers, although 

 I could detect nothing unhealthful in their surroundings. 



A fivsh lot of the insects was thereupon brought from 

 the field July 28, put into a large breeding-cage, and 

 kept as far as possible under normal conditions. A few 

 of .the bugs recently dead in the first outbreak were 

 broken in pieces and scattered about the earth of this 

 new habitation, or touched to the bodies of some of the 

 healthy individuals. A much larger number of this fresh 

 supply of insects was reserved for another small cage, 

 which, with conditions otherwise similar, was left uncon- 

 taminated by the bodies of any of the dead or diseased 

 insects. In three days one half of the insects in the in- 

 fected cage were dead, while in the untreated cage, with 

 so many more individuals, there were only two or three 

 dead. The dead bugs in the infected cage presenting 

 common characters, and a careful microscopic examina- 

 tion siiowing a well-defined bacillus uniformly abundant, 

 this preliminary test encouraged further experimentation 

 with this disease from a strictly bacteriological stand- 

 point, with a view to an elucidation of both its practi- 

 cal and scientific t'catui'cs. 



