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 Empusa muscaz 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. 
sphcurosperma (Fres.) Thaxter and E. arnericana 
Thaxter. E. sphcrrosperma 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. 
