ON THE PROPERTIES OF COCOONS. 517 



D. 

 in n. 



T. 



in grams. 



Due. 

 i» %■ 



K. 



R. 



Unw. 



W. Fl. 



in 



m. grams. 



24.6 



7.2 



10.2 



4 



I 



A 





25-9 



8.1 



9-9 











30.8 



^•S 



1 1.6 



5 



2 



C 





32.2 



9.6 



12. 1 



I 



2 







30.8 



8.7 



11.9 



3 









31-3 



8.9 



11.5 



3 



"■7 





37 



Races. . Diameter. Weight in Deniers. 



Cevennc (yellow) 23.7 /i 2.46 

 ( ) 2.83 



Valleraugue (white) 32.2 // 2.54 

 ( ) 2.98 



Milan ( ., ) 30.2 /i 2.59 



If the results which I have obtained 011 the relation of the weight in 

 deniers with the diameter of a filament, and those obtained in the 

 Laboratoire dc la vcr a soie in Lyon be correct then I do not 

 hesitate to say, that this disagreement between the weight in 

 deniers of a filament and its diameter is due to the specific gravity 

 or hygroscopic property of the filament, which may be different in 

 cocoons of different races. Later I expect to spend more time in 

 accurate experiments on these two points, viz. the specific gravity 

 and the hygroscopie property of a filament, and to publish my 

 results in a subsequent number of this bulletin. 



Further I may add some remarks on the properties of the 

 filam.ents examined by me as detailed above. It is commonly 

 known that the longer the filament of a cocoon is the greater is its 

 diameter ; thus the filament of a cocoon of an Akabiki, whose 

 length is 785 metres on the averai;e, measures 30.4 y. in diameter, 

 while the filament of a cocoon of a Koishimaru, Matamukaslii, and 

 of some bivoltin races, etc., whose length is less than 550 metres, 

 measurs only 26 /j. in diameter. In general, the worms of the 

 Akabiki race are much larger in size than those of Koishimaru, 

 Matamukaslii, and others ; and when the worms are larger in size, 

 their silk-glands must also be larger than those of the smaller 



