CHROMAT01D BODY IN PENTATOMA. 397 



Despite the small number of chromosomes I have not been 

 able to understand completely their history during the early 

 and middle prophases, when their elongate form and close 

 apposition to the nuclear membrane renders their complete analy- 

 sis in sections very difficult. Smear-preparations alone, I believe, 

 will fully clear up the facts. In the middle prophases (Fig. 31) 

 the chromosomes are characterized by the exaggerated character 

 of the longitudinal split (as compared with other insects I have 

 examined) the two halves being often quite as widely separated 

 as in the copepods (Hacker and his followers). Their number 

 at this time often appears to be five (instead of the expected 

 number, four), and in some cases even six, the diploid number. 

 This puzzling fact I can not yet fully explain; but it appears 

 to be due to the very wide separation of the two moieties of one 

 or both bivalents at the point where each is destined to undergo 

 "transverse" division in the first spermatocyte-mitosis. It is 

 at any rate certain that this is characteristic of the large bivalent 

 during the earlier period of its condensation, when it often gives 

 the appearance of two separate, longitudinally split chromosomes, 

 separated by a considerable space, and only connected by two 

 delicate strands (Fig. 19, a). That this pair represents the 

 large bivalent is fully established by later stages, in which all 

 intermediate conditions connect it with the large bivalent of the 

 metaphase figure (Fig. 19). The same is certainly true in some 

 cases also of the small bivalent (Fig. 20) ; but I am not sure 

 of the constancy of this. These facts raise the question whether 

 a very late end-to-end conjugation may not take place, in a 

 manner analogous to -that described by Gross ('04) at an earlier 

 period in Syromastes. The investigation of this point in smear- 

 preparations will probably yield interesting results. 



We now return to the history of the chromatoid body. No sign 

 of it is seen in the spermatogonia, nor can it be positively identified 

 in the spermatocytes until some time after the synizesis. But 

 already in the stages immediately following synizesis, as the 

 chromosome-threads are beginning to spread through the nuclear 

 cavity, from one to three very small, deeply staining granules 

 make their appearance in the protoplasm, usually not far from 

 the nucleus, each of which may often be seen to lie in a clear, 



