596 Toyama, On certain characteristics of the Silk-worm etc. 



markings are those of the eye-brow on the second segment, a pair 

 of horse-shoe shaped markings on the fifth, and a pair of roundish 

 markings on the eighth. 



11. -'Smudged" or "Kasuri" worms. These are found in 

 Japanese breeds. They are characterized by the presence of mark- 

 ings like light smudges over the dorsal part of the body. 



12. Pale worms, which have lost nearly all the markings. 



13. Pale smudged worms which are the pale form of the 

 smudged worms just referred to. 



These latter^six kinds (Nos. 8 13) of markings may be divided 

 into two classes, one of these having "special markings" and the 

 other having no special markings. By the words "special markings", 

 we mean those markings which are found on the second segment 

 or the kl eyebrow", a pair of horse-shoe-shaped ones on the fifth, 

 segment, and a pair of roundish ones on the eighth. The other 

 markings which decorate the general surface of the body will be 

 called "general markings", except certain markings which are found 

 on the ventral side of the segments. 



The moricaud, Chinese black, normal-patterned, and smudged 

 worms, belong to the category which possess the special markings, 

 and the latter two, pale and pale smudged, to the category of those 

 which do not possess the special markings. They are Mendelian 

 allelomorphs, the presence being dominant towards the absence. 



In the general markings, the Chinese black stands first in 

 dominancy, then in order come the moricaud, the normal smudged, 

 pale, and pale smudged markings. 



The relation between normal, smudged, pale, and pale smudged 

 is very interesting because if we cross certain pale worms with 

 smudged worms, the results will be the production of all normal 

 F! which gave in F 2 9 normals: 3 smudged: 3 pales and 1 pale 

 smudged. In the mating between pale and pale-smudged, the F 1 

 is all pale worms, which segregate into 3 pales to 1 pale-smudged 

 in F 2 . The phenomena of inheritance are quite the same as those 

 observed by Bateson in fowls and many plants 5 ). 



In the silk-worm larvae we may therefore enumerate the follow- 

 ing Mendelian characteristics: 



Dominant. Recessive. 



1. Trimoulting characteristic. Tetra-moulting characteristic, 



2. Yellow blood characteristic. The absence of yellow colour characteristic. 



3. The presence of some pigments in The absence of pigments, 

 the hypoclerm. 



4. The presence of knobs. ,, knobs. 



5. The presence of spotted markings. ,, spotted markings. 



5) Bateson, W. - - Mendel's principles of Heredity. 1909. 



