Notes on the Spermatogenesis of the Wild 

 and the Domesticated Silkworms. 



By 



Naohide Yatsu. 



Although the spermatogenesis of some lepidoptera has been 

 lately studied with especial reference to the chromosomes by the 

 late Miss STEVENS ('05), MUNSON ('06), Miss DEDERER ('07) and Miss 

 COOK ('io), jet that of the silkworm has not been undertaken since 

 the apperance of TOYAMA's papers ('94 a and b). What one finds in 

 the later literature regarding the germ-cells of the silkworm is 

 limited to fragmentary notes by La Valette St. George ('97), Hen- 

 NEGUV ('98) and Meves ('03) on structures other than the chromo- 

 somes. Such paucity of works on the spermatogenesis of the silk- 

 worm is rather remarkable, since in most countries the material can 

 be obtained without difficulty. 



As there are quite a number of varieties in the domesticated 

 silkworm, I thought that they would be an excellent object for the 

 study of correlation between their morphological features and the 

 chromosomal characters. So I undertook a comparative study of 

 spermatogenesis of the wild silkworm (Thcophila mandriano) and of 

 the following seventeen varieties of the domesticated silkworm (Bombyx 

 mori) : 



I. Dainyorai \ 



2. Aojiku 



3. Koishimaru 



4. A ray a 



5. Watako 



6. Seihaku 



7. Shirojima x Kurojima 



8. Kasasagi 



9. Corean No. I (dark brown) 

 10. Corean No I Cgrccn) 



