GOLDSTEIN: RESTING SPORES OF EMPUSA MUSCAE 325 
The remainder of the conidiophore tube, as Brefeld also ob- 
served, disintegrates. The collapsed, shrunken, and disinte- 
grating hyphal tubes can be seen filling the openings between 
the segments of the abdomen and projecting a little from the 
body in sections of flies in which the conidiophores have already 
discharged their conidia. Great numbers of bacteria are always 
present feeding upon the contents of the disrupted hyphae. 
After the discharge of conidia, there still remain within the 
abdominal cavity numerous hyphal filaments and other hyphal 
fragments which have not been able to reach the exterior. As 
long as suitable moist conditions are present, these hyphal tubes 
remain alive and unaltered and are later able to force their 
way between the collapsed conidiophores to the exterior to form 
and discharge their conidia. If, however, the weather is dry, 
the development of conidia may be checked, and it is probably 
under these conditions that the resting spores are formed. 
The terminally formed resting spores arise as swellings in 
the terminal regions of hyphal tubes and are finally cut off by 
cross walls (Fic. 4). Within the hyphal membrane the heavy 
wall is formed and a somewhat pyriform or more or less oval 
resting spore results. Those resting spores which are formed 
along the hyphal tubes are generally more rounded in form. 
I have found two, three or four round, thick-walled spores oc- 
curring in a chain, connected by the collapsed and emptied 
hyphal tube membrane in which they arose (Fics. 5 and 7). 
Not all the resting spores are round or oval. Some are simply 
portions of the hyphal tube which have become only slightly 
more swollen than the original width of the hyphal tube. 
Resting spores are found only in the abdominal cavity, 
although traces of vegetative mycelial threads can be seen in 
the thorax and head of the insect. The germ tube first makes its 
entrance into the abdominal cavity as Brefeld found, and the 
fungus passes most of its vegetative state feeding upon the 
body juices and soft tissues which are found in this region. 
SUMMARY 
Resting spores are formed in the life cycle of Empusa Muscae. 
Failure to find them on the part of Brefeld and other students 
is apparently because they are formed very late in the develop- 
ment of the fungus. - 
