CHROMOSOMES OF THE REDUVIIDAE 



341 



lus. In this early stage it seems to be pretty conclusive that the 

 nucleolus is formed by an aggregation of chromatin. This agrees 

 with Foot and Strobell's interpretation of the formation of the 

 nucleolus in Protenor. Figure 7, C, D and E are later stages in 

 the development of this nucleolus. These figures show that it 

 increases in size rather rapidly and becomes large in proportion 

 to the size of the nucleus. This rapid growth along with the fact 



Fig. 7 Gelastocoris oculatus Fabr. ^4, an oogonial nucleus showing no nucle- 

 olus is present; B, a young oocyte nucleus in which some of the chromatin is col- 

 lecting together to form the nucleolus (nuc); C and D, young oocyte nuclei, show- 

 ing the growth of the nucleolus; E, young oocyte nucleus showing the nucleolus at 

 approximately its maximum size (in this case the nucleolus is not stained so 

 intensely as in the others and eight darker bodies lie imbedded in it) ; F, an oocyte 

 nucleus shortly after synapsis with the chromatin as doubly split threads and the 

 nucleolus much reduced in size. X 2275. 



that no chromatin is added after its beginning indicate that its 

 rapid growth is due to the addition of something other than chro- 

 matin. Figure 7, E also indicates the same thing since here the 

 nucleolus does not stain uniformly but darker bodies can be seen 

 within it. In this case there are eight of these darker bodies and, 

 while the evidence is not conclusive, it seems probable that they 

 are the idiochromosomes and the whole structure is a nucleolus 

 or plasmosome in which the idiochromosomes are imbedded. 



