526 ROBERT W. HEGNER 
The most plausible conclusions from a consideration of these ob- 
servations and experiments are that every one of the eggs in which 
Keimbahn-determinants have been described, consists essentially of 
a fundamental ground substance which determines the orientation; 
that the time of appearance of Keimbahn-determinants depends upon 
the precociousness of the egg; that the Keimbahn-determinants are 
the visible evidences of differentiation in the cytoplasm; and that these 
differentiated portions of the cytoplasm are definitely localized by cyto- 
plasmic movements, especially at about the time of maturation. 
This conclusion still seems to me the only tenable one at the 
present time and applies, I believe, to the germ-line-determinants 
in Copidosoma, as well as to those in other animals. 
2. Apanteles glomeratus.* 
Another Hymenopteron that resembles Copidosoma in some 
respects is Apanteles, a parasite of the larva of the cabbage 
butterfly. An abundance of material was obtained in the 
month of August, 1914. The pupae and recently emerged 
adults were liberated from the cocoons, and their abdomens were 
fixed either in Bouin’s picro-formol solution or Carnoy’s mixture. 
As in Copidosoma, the ovaries contain oocytes in all stages of 
growth and hence their history could be traced without much 
difficulty. 
The history of the oocyte nucleus. Oocytes at a very early 
stage (fig. 71) acquire an epithelium (e) and are accompanied 
by a group of nurse cells (n). The chromatin is large in amount 
and massed into an irregular homogeneous body. As growth 
proceeds (fig. 72) this chromatin-mass expands, revealing the 
spireme of which it consists. Soon the entire nucleus is filled 
with a network of chromatin threads (figs. 73-76), a condition 
that persists for a considerable part of the growth period. When 
the oocyte has reached its definitive size (fig. 77), the chromatin 
threads contract into chromosomes which apparently unite in 
pairs, as in Copidosoma (fig. 60), and become arranged side by 
side upon an asterless spindle (fig. 78). This stage is followed by 
the condensation of the chromosomes, as shown in figure 79. 
No later stages in the nuclear history were present in my material, 
31 am indebted to Dr. H. L. Viereck for the identification of this parasite. 
