ON THE PROPERTIES OF COCOONS. 



509 



6. Kimayu (green) 



7. Hakuriu (white) 



8. 0-setsu ( ,. ) 



9. Koishimaru, produced at Hokkaido (white) 



10. Chosan (white) 

 Bivoltins 



11. Kumako (white) 



12. Natsuko ( ,, ) 

 Foreign races 



13. Chinese (white) 



14. Italian ( ) 



0-setsu is quite new race produced by our silkworm raisers. Its 

 eggs do not change their colour after deposition, and remain a light 

 yellow till they hatch in the following year. The eyes of the moths 

 are not tinged with black, but light greyish yellow. Chosan is a 

 race whicli has been produced in our Agricultural College. It was 

 derived from Akabiki by feeding the worms with the leaves of 

 Broussonetia papyrifera twice a day for the last three years. 



The properties of the cocoons of each of the above mentioned 

 races were examined with reference to the following ten points : — 



I. 



Length of the filament of a single cocoon... 



... (L.F.) 



2. 



Weight ,, ,, ... 



... (W.F.) 



3- 



Weight in deniers ,, ,, ,, 



... (W.D.) 



4- 



Diameter ,, ,, 



... (D.) 



5- 



Tenacity ,, ,, ,, ... 



... (T.) 



6. 



Ductility (Elasticity) ,, ,, ,, 



... (Due.) 



7- 



Knots 



... (K.) 



8. 



Ruptures 



... (R.) 



9- 



Feature of the unwinding of the filament of a sin^ 



xle 





cocoon 



... (Unw.) 



ID. 



Weight of flocks of a single cocoon 



... (W.Fl.) 



The weight of the filament and that of flocks were taken in the 

 air-dry condition. Knots were counted in the first 238 meters of 

 the filament, and ruptures in its whole length. The feature of 

 unwinding was classified into three divisions indicated respectively 

 by the letters A, B, C, of which A indicates very good, B good, 

 and C tolerable. Flocks are those parts which form the extreme 

 outer and inner layers of a cocoon and can not be reeled. 



The results of examination are shown in the following table : — 



