64 THE HOUSE FLY—DISEASE CARRIER 
continually reproduced by budding or division until 
the insect is more or less completely filled with them. 
These fragments are called hyphal bodies. They con¬ 
tain a highly concentrated, fatty protoplasm and are 
capable of subsequent and often very extended develop¬ 
ment. 
When the mass of these bodies has been completed 
and the death of the insect attacked has occurred, the 
fungus may proceed at once to the completion of its 
development under proper conditions of temperature 
and moisture, but if these conditions are absent a rest¬ 
ing stage ensues in which the contents of each hyphal 
body becomes surrounded by a single wall which in¬ 
creases in thickness as the resting stage continues. The 
fungus may remain dormant in this condition for a 
considerable period. Doctor Thaxter has observed the 
hyphal bodies germinating after several weeks, and 
thinks that they probably retain their vitality for a 
much longer period, and may perhaps hibernate under 
certain circumstances. 
When a moist atmosphere and a sufficiently high 
temperature come they germinate with great rapidity. 
With the common house fly fungus (Enipusa tmiscce ) 
a slight change in the amount of atmospheric moisture 
is sufficient to bring about germination. This, accord¬ 
ing to Thaxter, is very noticeable on the seashore, 
where slight changes of the wind from the water or 
from the shore bring about a very rapid and noticeable 
effect upon the flies thus parasitized when watched in 
the ordinary atmosphere of the house. With other 
