68 THE HOUSE FLY— DISEASE CARRIER 



that the city of London local government board on 

 public health and medical subjects is now aiding Dr. 

 Julius Bernstein in a detailed investigation of the life 

 history of Ernpusa miisccc and in an attempt to cultivate 

 it in artificial media, with the object, if possible, of em- 

 ploying these cultures to destroy flies on a large scale. 



Two other species of Empusa are recorded by Thax- 

 ter as developing in the typhoid fly. These are E. 

 sphcerosperma (Fres.) Thaxter and E. americana 

 Thaxter. E. sphcerosperma is peculiar for the great 

 diversity of its hosts, since it destroys insects of all or- 

 ders except that to which the grasshoppers belong. It 

 is a very common form and often produces very con- 

 siderable epidemics among insects. It is recorded as 

 destroying the clover weevil in great numbers on one 

 occasion near Geneva, N. Y., by Dr. J. C. Arthur, and 

 in 1909 produced an extraordinary epidemic in the 

 same insect in the vicinity of Washington, D. C. 



As it happens, an allied insect, probably accidentally 

 imported from Europe, is causing great damage at the 

 present time in the alfalfa fields in Northeastern Idaho. 

 Prof. F. M. Webster of the Bureau of Entomology at 

 Washington immediately conceived the idea of attempt- 

 ing to introduce this fungus from Washington into 

 Idaho, in the hope that it would attack the alfalfa 

 weevil. Owing to the dry climate out there, however, 

 the experiment failed; the conidia would not develop, 

 and it would seem very difficult if not impossible to 

 produce, artificially, moisture conditions which will en- 

 able alfalfa growers to handle this disease practically. 



