PSYCHE. 



EXPERIMENTS FOR THE DESTRUCTION OF CHINCH BUGS 



BY INFECTION. 



BY FRANCIS H. SNOW, LAWRENCE, KANSAS. 



[Annual address of the retiring president of the Cambridge Entomological Club, 12 February, 1892.] 



I regret my inability to be present at 

 the annual meeting of the Club on the 

 8th inst.* I, however, forward the fol- 

 lowing account of my experiments for 

 the destruction of chinch bugs in the 

 field by the artificial introduction of 

 contagious diseases. This may serve 

 as my annual address as president of 

 the Club. One of your former presi- 

 dents, Prof. S. A. Forbes of Illinois, 

 adopted a similar subject for his annual 

 address. 



At the outset, I desire to call your 

 attention to the difference between my 

 own experiments and those of Prof. 

 Forbes. The latter has been working 

 for several years in the line of commun- 

 icating contagious diseases to chinch 

 bugs by means of artificial cultures of 

 the microscopic plants which produce 

 disease. He has not, however, thus 

 far, been successful in communicating 

 disease to chinch bugs in the fields by 

 means of artificial cultures. In my 

 own experiments, continued now for 

 three years, I have proceeded upon a 

 different basis. Recognizing the failure 

 of previous attempts to destroy chinch 



*The address reached the Club too late for the meet- 

 ing of S January. 



bugs by the application of artificial cul- 

 tures of disease germs, I conceived a 

 very simple idea of making the chinch 

 bug himself the vehicle for the commu- 

 nication of disease in the field. 



Dr. Otto Lugger of the Minnesota 

 Agricultural Experiment Station in the 

 autumn of 1SS8 distributed in certain 

 fields infested with chinch bugs the 

 dead bodies of bugs that had died in 

 other fields from disease which was 

 naturally present. Dr. Lugger, how- 

 ever, was in doubt as to whether disease 

 was actually communicated in the field 

 by these dead bugs, thinking that per- 

 haps the disease after all might have 

 reached the fields in which he distrib- 

 uted his material by the natural progress 

 of the disease from field to field. So 

 far as I know, Dr. Lugger did not fur- 

 ther continue these experiments, and 

 made no investigations in the labora- 

 tory with reference to preserving the 

 infection through the winter and exper- 

 imenting in the following season with 

 infection thus preserved. 



In June, 1SS9, I obtained the first 

 material for my experiments from a 

 farm in Morris County, Kansas. This 

 material consisted of Empusa, deter- 



