344 FIRST FORMS OF VEGETATION. 
able numbers adhering to window-sills, walls, and 
various articles of furniture in our rooms. In a 
few days they die, but strange to say their appear- 
ance is so little altered, that it is impossible with- 
out actual examination to tell that they are dead. 
When dying in the ordinary way, they always 
draw up their legs, and cross them beneath their 
bodies ; but when they perish of this disease, the 
legs are stretched out supporting their bodies, and 
retaining them in their natural position. The pro- 
boscis is protruded, as if in the act of imbibing 
nourishment, and their whole appearance is that 
of vigorous healthy flies that have alighted for a 
moment, and may be expected in the next to take 
wing and fly away. The only difference observed 
is a whitish halo, like a sprinkling of flour, about 
three inches in circumference, which surrounds 
them like a magic circle, and consists of the min- 
ute dust-like spores shed by the fungus that has 
attacked them. When more attentively exam- 
ined, however, the abdomen is seen to be much 
swollen, the rings composing it being separated 
from each other by inter-spaces, occupied with 
white prominent zones of vegetable growth. The 
body is a mere empty shell, reduced by the 
slightest touch to a dry friable powder, and lined 
with a thin, white, felt-like layer of mycelium, the 
entire viscera and all the juices being consumed 
