. a 
—T 
1906] ' OLIVE—DEVELOPMENT OF EMPUSA 205 
I have not yet completely solved satisfactorily to myself the pecul- 
iar method of abjection of the spores of my undetermined species of 
Empusa. I am inclined to think, however, that this method, in certain 
respects, is unlike that described above. In this form the conidio- 
phores come to the surface, become cut up by septa into uninucleate 
segments, and proceed to branch profusely (jigs. 23, 25). The cell 
terminating each branch pushes out in a peculiar manner. Instead 
oi forming a large basal vesicle as an explosive mechanism in the usual 
manner, as described above, here the protoplasm appears to cut itself 
off from behind by means of one or more successively formed walls 
(figs. 22, 24, 26). A minimum of protoplasm seems to be lost in 
the process, and this cut-off protoplasm soon assumes a peculiar 
granular appearance. In this condition it is probably dead, for these 
cut-off cells appear soon to lose their turgescence. _ It is difficult to con- 
ceive of a forcible discharge of the spore in this instance, especially if 
it be true that the protoplasm of the basal cells is dead and thus inca- 
pable, through loss of turgidity, of functioning as an explosive mechan- 
ism. The process here rather seems to be that, by means of these 
successive abjunctions, the uninucleate spores are pushed off with but 
little force, and that they are probably followed out of the thick, gelatin- 
ous wall of the mother hypha by other cells pushed up from below. It 
may be, however, that further studies on fresh material of this species 
will change this impression of subterminal proliferation. 
Figs. 45 and 46 represent the terminal portion of large hyphae of 
E. culicis which are destined to form resting spores; and figs. 47 and 
48, two fully formed, thick-walled resting spores. Such hyphae as 
are shown in the first two figures are distinguished from conidiophores 
by being much larger, and, further, they contain four or five nuclei, 
instead of two. I have traced these hyphae in sections back to 
large “hyphal bodies,” but I was unable to follow their complete 
history. Whether the thick-walled resting spores of this species are 
therefore true zygospores, or azygospores, as they are termed in THAX- 
TER’s monograph, I am not prepared to say. I have not been able, 
however, to confirm VUILLEMIN’s assertions (:00) as to the nuclear 
fusions in the azygospores of Entomophthora gloeos pora. 
UNIVERSITY OF WISCONSIN, 
Ison. 
