GOLDSTEIN: RESTING SPORES OF EMpusA MuSCAE 321 
OBSERVATIONS 
In September, 1921, I began a study of Empusa Muscae and 
had under observation great numbers of flies, many of which 
were attacked by the fungus and died of the disease. I fixed 
and embedded for cytological study both fresh material and 
some very old dry specimens of flies. These dried house flies 
were found sticking to walls and windows by means of their 
proboscides. The live flies, which I had under observation and 
which died of the disease, came from the same locality near 
Ridgewood, New Jersey. 
The dried flies were put in Merkel’s solution for two hours, 
followed by a diluted solution of Flemming’s weak for twenty- 
four hours. The material was run up into paraffin in the usual 
way, and the sections were cut 5 thick and stained with 
Flemming’s triple stain. The sections of two of these flies 
showed multinucleated, rounded, thick-walled spores in their 
abdomens. 
Having found resting spores in these dried house flies, I 
immediately began to search about for other dried specimens. 
Several dried flies were found sticking by means of their probos- 
cides to the white porcelain glass shades around the electric 
lights in the laboratory. Evidently in making transfers of the 
flies under observation from one glass chamber to another, 
diseased flies had escaped into the room, and had attached 
themselves to the glass shades. These dried flies showed further 
evidence of having died of the disease, since, between the seg- 
ments of the abdomen, the thin membrane still projected as if it 
had been pushed out by the pressure of the conidiophores, and 
the segments of the abdomen were still somewhat apart. Upon 
sectioning and staining this material, the same form of resting 
spores was found again, although the material was not as good 
as the first. 
In January, I secured a number of dried flies from house 
walls in the same locality, and resting spores were also found 
in this material. In dry specimens of flies secured about dwell- 
ings in New York City this year (1922) I have again found resting 
spores, some fully formed, and others in process of formation. 
requently such old dry specimens show only traces of disin- 
tegrated, mycelial threads and are often filled with bacteria of 
