324 GOLDSTEIN: RESTING SPORES OF EMpusA MUSCAE 
spore, such as Vuillemin describes for Entomophthora gleospora. 
The younger, thin-walled spores contain about the same number 
of nuclei as the very thick-walled spores. 
Oil globules are present in the older spores. These usually 
occur as a few large drops. There may be a single large oil 
drop present, so that the protoplasm appears to be pushed to 
one side of the spore, and the nuclei are then grouped closely 
together in the denser mass of protoplasm. Generally the 
nuclei are scattered rather irregularly through the protoplasm. 
In the young spores, the protoplasm is more or less homogeneous 
and fine granular threads connect the nuclei (Fics. 6 and 7). 
The resting spores show an outer thin wall or membrane 
around them, which is probably the old hyphal wall. Inside 
this is the thickened wall. This wall is of an even thickness 
around the entire spore and is quite smooth even in mature 
spores. The wall appears to be composed of a single layer, 
and probably grows in thickness by deposition of material from 
the outer region of the protoplasm. Within the thick wall is 
the rounded protoplasmic mass, which may be only very slightly 
withdrawn from the thick wall, or very much so, the latter 
condition being due probably to poor fixation (FIG. 5). 
_ The resting spores are obviously asexual in origin. They 
are chlamydospores in the strict sense. They arise most com- 
monly at the tips of short hyphae or hyphal fragments (FIGs. 
3 and 4) or by the division and rounding up of the protoplasm 
in the hyphal filaments themse’ves (Fic. 7). In both fresh 
and stained material, I have recently found some evidence that 
they may arise as buds on hyphal fragments or hyphal bodies 
(Fics. 2 and 9). 
The hyphal cells, at the end of the nutritive period of the 
fungus, give rise to long hyphal tubes which grow out toward 
the body walls of the host. These hyphal tubes are non-septate 
and contain many nuclei. They are always unbranched. Many 
reach the body wall of the insect, and travel along parallel to it, 
until the thin membrane between two segments of the abdomen 
is reached. Here, with other tubes that have reached this 
region directly, they push out the membrane and finally grow 
out to the exterior. At the tip of each conidiophore, a conidium 
arises as a bud and, when mature, is finally cut off by an ingrow- 
ing wall. The conidium is forcibly abjected by the bursting of 
the upper swollen region of the conidiophore. 
