T. CHARTERS WHITE ON EMPUSA MU8C2E, 213 



instances of vegetable fungi investing insects, but lie does not 

 attempt to account for its origin. 



The disease manifests itself first in the fly being stupid and 

 " groggy," sluggish in its movements, and pertinacious in its visits to 

 one spot. If at this time the fly be examined, a great number of 

 minute free-cells may be detected, in what answers the purpose o 

 blood in these creatures, and the fly settles down to its last resting 

 place, which is generally some warm spot indoors. I have never yet 

 found many out of doors. Under the influence of warmth, and pro- 

 bably the moisture derived from the soft tissues of the body, the 

 fungus grows apace, till it consumes, not only the life of the fly, but 

 all its tissues, excepting the tracheal system and the chitinous parts. 

 It is not every fly that perishes this way, but only some, and that 

 would seem to argue the existence of a predisposition to this disease. 

 It seems to affect the housefly, " Musca domestical and not the 

 blow fly, " Musca vomitoria." It does not appear from the few 

 observations that I have been able to make, that the disease is conta- 

 gious, as I have confined healthy specimens of the house fly with 

 plenty of fresh air, with some of the dead flies covered with the 

 spores of Empusa musca?, and although they have died from the 

 confinement, they have not had a particle of the fungus within their 

 bodies, so that we have yet to know more of the life history of this 

 Empusa, and, as at this season of the year many infected flies can 

 be obtained, I thought it might be of service if I called attention 

 to the subject this evening for a few niinutes, as an accompaniment 

 to my slide. 



