PARASITES OF SIMULIUM LARVAE 77 
basis of the mass. This irregularity is apparently produced by 
the swelling of the sporoblasts, for it is at this period of develop- 
ment that the sporont usually loses its globular shape.. The 
elliptical spore measures about 4p x 2.5u and is less pronouncedly 
ovoid than that of Glugea fibrata. On treatment with iodine 
a filament is ejected. Unfortunately I have no preparations 
showing the evaginated filament, but in a free-hand sketch of 
an unstained specimen I drew it about ten to fifteen times the 
length of the spore and this is roughly its length. My prepara- 
tions were also stained with haematoxylin so I was unable to 
see the nuclei, but in figure 14 I have, by analogy with G. fibrata 
indicated their probable position. I observed in unstained spec- 
imens that when the filament was ejected by iodine the spore 
contents shrank in a similar manner to that described for G. 
fibrata, giving the spore the appearance of figure 13. 
It is seen from this that the ejection of the filament in both of 
these species is accompanied by a decided enlargement of the 
vacuole, which suggests that its fluid contents are swollen by 
the iodine entering through the shell by osmosis, and that the 
as yet undiscovered function of the vacuole may have some con- 
nection with the ejection of the filament. 
The host of G. multispora is the larva of Simulium vittatum 
and Simulium bracteatum. It was found in one out of four 
larvae taken from a part of the stream in the Arnold Arboretum, 
where larvae were very scarce. Three other infested specimens 
were taken at Hyde Park and Franklin Park in the neighborhood 
of Boston. 
NOTES ON THE GENERIC POSITION OF THE SPECIES DESCRIBED 
Although I have placed all three species above described in 
the Genus Glugea of Thélohan, the first two, especially G. 
bracteata, according to Gurley’s interpretation of the genus (94), 
cannot be included, for his definition of the genus is as follows. 
‘““Glugeidae possessing a myxosporidium, and in which the pan- 
sporoblast produces an inconstant but large number (always more 
than 8) of spores, pansporoblast membrane not subpersistent.’* In 
3 JTtalics mine. 
