2 l6 



N. YATSUr 



11. Shin-en 



12. Ryükaku 



13. Birüdo 



14. Chinese 



15. Bagdad 



16. Bas- Alps 



} Turkish races. 

 I European races. 



Chinese races. 



17. Italian No I 



As fixing fluids acetic-sublimate and Flemming'S solution were 

 used. The latter preserves excellently both the cilia and the V- 

 shaped centriolcs of the primary spermatocyte, which were described 

 and figured by MEVES ('97) and HENNEGUY ('98). 



It is interesting to note that the testes of all the yellow cocoon 

 races are yellow as are also their silk-glands and body-fluid. In those 

 races, moreover, the testes grow slower than in the white cocoon races, 

 so that the larvae of the former yield testes of suitable stages for the 

 study, when they have grown to a size much larger than those of 

 the latter. 



I experienced some difficulty in getting the materai of the wild 

 silkworm. A large percentage of its larvae was found to be infested by 

 the maggot {Ugimia sericarid), and only a few individuals could be 

 obtained, that were free from the parasites and yielded good testes for 

 my purpose. 



Besides the testes, young ovaries were cut into sections in order 

 to study the oogonial division. 



Here I must thank Professor ToYAMA of the Agricultural College 

 and Mr. HayaSHI of the Tokyo Scricultural Institute for the kindness 

 shown me in many ways, especially in providing me with the material. 



As will be seen from the appended figures, all the chromosomes 

 of the silkworms look almost alike, there being found no perceptible 

 differences both in shape and size. A constant mode of arrangement 

 of the chromosomes at the metaphase cannot be detected. Of the 

 seventeen varieties, that came under my examination, I could find no 



Results. 



