522 ROBERT W. HEGNER 
according to Silvestri, are the parents of all of the germ cells, 
a conclusion that seems justified, since a similar body in monem- 
bryonic parasites has been definitely traced until it becomes 
distributed among the germ cells. 
In my preliminary report on Copidosoma gelechiae I pointed 
out the improbability of the origin of the ‘nucleolo’ of Silvestri 
from the nucleolus of the germinal vesicle, and concluded from 
the material I then possessed that this body consists of all of 
the chromatin from the oocyte nucleus which had formed into 
a compact mass. To explain the presence of both this body and 
an egg nucleus it was suggested that two oocytes might fuse end 
to end, the posterior one furnishing the ‘nucleolo’ and the other 
the nucleus. The eggs of these insects, when ready to be laid, 
are long, with a very slender bent portion between the two thicker 
ends, as shown in figure 54. My material consisted only of 
serial sections cut 2 and 4u thick, and, as Silvestri (14) has pointed 
out, I considered sections through the anterior and posterior ends 
of an oocyte as sections of complete oocytes. This is a mistake 
that I now wish to acknowledge, but is one that could hardly 
be avoided without good in toto preparations. With the aid of 
such preparations I have been able to confirm Silvestri’s account 
in most respects. My conclusion, however, that the ‘nucleolo’ 
of Silvestri is not the nucleolus of the oocyte nucleus is correct, 
and my account of the history of the oocyte nucleus up to its 
change into an oval mass of chromatin is also correct, as indicated 
by the study of new material, and by the confirmatory account 
by Martin in Ageniaspis. I am indebted to Dr. R. W. Glaser 
for this new material. 
Martin (14) records the presence of three kinds of cytoplasmic 
inclusions in the growing eggs of Ageniaspis: (1) a cloud of 
granules near the posterior end, (2) a ‘nucleolus’ also near the 
posterior end, and (3) a few chromatin granules cast out by the 
nucleus. The ‘nucleolus’ is of particular interest to us, since it 
is undoubtedly a body similar to the ‘nucleolo’ of Silvestri. 
Martin was able to trace this ‘nucleolus’ from the young oocytes 
to the three-cell stage in the cleavage of the developing eggs. 
It appears first as a small group of granules lying in the midst 
