G6 
tubes. A short time previous to death all movement ceases and 
the body becomes turgid, in consequence of the greatly increased 
development of the fungus cells, some of which are very large. 
The cells now regain their globular outline, at one or two points 
filaments are formed, which interlace and throw out branches, and 
gradually surround the internal organs, but do not appear to 
penetrate them ; they however soon appear to obtain nutriment at 
their expense, and finally death ensues, the legs and wings become 
extended, the proboscis obtruded and adhered closely to the glass, 
&c. The fluids and internal organs are gradually absorbed by the 
fungoid parasite, the radial portion continues to elongate, and the 
opposite end gradually develops a clavate head, the internal growth 
of the Empusa enlarges the abdomen and the segments separate 
from each other ; after the lapse of several hours the delicate 
membrane uniting the segments is perforated by the clavate ends, 
which now make their appearance on the external surface, forming 
white rings round the abdomen, the clavate end grows quickly, a 
delicate diaphragm is formed at the lower extremity ; the parasite 
now consists of two cells, the ujDper portion becomes filled with 
plasm and a mucellular spore is formed which the elastic pressure 
of the cell projects some little distance from the parent ceU ; these 
spores form the white halo surrounding the body of the fly. 
Some observers attribute the presence of the Empusa musca 
to a vitiated condition of the circulating fluid, as the true spores 
have not been detected in the fly. Perhaps the protoplasm that 
formerly replaced the wasted tissues is no longer appropriated and 
develops into a lower organism, which in its turn pulls to pieces 
the former material. 
Others are disposed to think that the spores attach themselves 
to the exterior of the fly, and when favourable circumstances occur 
for their development they penetrate the spiracles, and the growth 
of the Empusa commences. Dr. Cohn considers this disease to be 
analogous to the muscardine in the silkworm, but as I have not 
had an opportunity of seeing that disease, I am unable to give any 
opinion as to the correctness of the doctor’s views. 
I have endeavoured to produce the fungus in other insects — viz., 
the blow-fly, the bee, and drone fly, but without success. The 
plan I adopted was to confine the insects tinder a glass in which 
one or more dying or dead flies were placed, but in no instance was 
