58 



Annals Entomological Society of America [Vol. X, 



Native coccobacilli isolated from the digestive tract of 



Locusts. 



In the first part of this paper we stated that our failure was 

 probably due in part to the immunizing effect of native strains 

 of coccobacilli. 



We have described altogether sixteen organisms, some 

 practically identical with d'Herelle's organism, the others more 

 or less closely related. 



The first culture was obtained from an individual of 

 Melanoplus bivittatus which dropped dead near one of the 

 authors at some distance from the laboratory, before any exper- 

 iments were tried in the field. This coccobacillus showed a 

 progressive increase in virulence similar to Coccobacillus 

 acridiorum. 



The other cultures we obtained both from apparently 

 healthy locusts and from diseased or dead ones. In addition to 

 those described a few other organisms were isolated, but we 

 have included only those which are allied to Coccobacillus 

 acridiorum and which injected into the intestinal canal of locusts 

 cause death within twenty-four hours. 



TABLE VII. 



SOURCE, NUMBERS, ETC., OF THE COCCOBACILLI DESCRIBED. 



