STUDIES ON GERM CELLS 531 
a large part of the posterior region; at this stage the term ‘hin- 
terer Polkern’ is applied to it. Its later history was not followed. 
It is worth mentioning that the follicle cells of the oocytes 
divide by mitosis (fig. 93) and not by amitosis as has been 
described in some insects. 
Secondary nuclei in the oocytes of the mealy rose gall-fly Rhodites 
ignota. The eggs of this gall-fly (fig. 94) possess a very long 
anterior process, as in the two species already described, and the 
nucleus is similarly placed, but no body occurs at the posterior 
end. Of particular interest here is the presence of a large num- 
ber of secondary nuclei at certain stages in the growth of the 
oocyte. ‘These secondary nuclei were first observed near the 
periphery, as indicated in (fig. 95), which is part of a transverse 
section. ‘They are very small and appear to consist of a single 
body that stains like chromatin, and are surrounded by a mem- 
brane. The occurrence of deeply staining granules without 
these membranes, and the various sizes of the secondary nuclei 
formed, lead to the conclusion that chromatin granules from the 
oocyte nucleus, from the nurse cells, or from the follicle cells, 
migrate into the cytoplasm and become the center of origin of 
the secondary nuclei. In later stages these nuclei are all larger 
and form a layer a slight distance from the periphery of the 
oocyte (fig. 96). They vary greatly in size as shown in figure 97, 
but exhibit all the characteristics of true nuclei. No secondary 
nuclei could be found in older oocytes, but what becomes of them 
was not determined. 
Summary of Part III. A. Copidosoma gelechiae. 1. The 
chromatin in the oocyte nucleus forms chromosomes at an early 
stage in the growth period (fig. 51). These chromosomes unite 
near their ends in pairs (figs. 52 and 58) and then become ar- 
ranged in a parallel series upon an asterless spindle (figs. 53, 59, 
60). Condensation then occurs and an apparently homogeneous 
oval-shaped mass of chromatin is formed (figs. 54 and 62-65). 
The number of pairs of chromosomes is eleven (fig. 61) or twelve. 
The nuclear history is essentially as described in my preliminary 
4 Summaries of Parts I and II will be found on pages 505 and 520. 
