spinners of Silk. 



309 



its exit when it becomes a moth will be easy, whilst entry on the part 

 of any intruder will be difficult. At this upper part the cocoon is not closed in but 

 tapers to a point formed by straight silken hairs converging. These may be pushed 

 against from outside without yielding, but very slight pressure from within will 

 serve to separate them and reveal the opening. At a little distance inside, this 

 structure is repeated, so that the chrysalis reposes in safety behind two puzzle 

 doors which oppose no obstruction to the moth. 



In a North American species of silk-moth ^ this type of cocoon is improved 

 upon. There are in fact two cocoons placed one within the other with a packing 

 of loosely spun threads between the two walls, which keep the inner cocoon in 

 place, as shown in the photograph of the cocoon in section. This arrangement 

 must protect the contained chrysalis from great changes of temperature ; but 



P>'oto by] [H. Bnstin. 



IHe Arrindi Silk-.Mot!i. 

 Another sillv-moth of India and the East, which is somewhat larger than the tusseli-uiotli. Us yellowish-olive wings arc banded with 

 white and bear crescent-shaped white marks edged with yellow and black. The photograph shows the actual size. 



though admirable for the chrysalis and the moth, it is not appreciated by those 

 who would convert its filaments into woven tissues. The upper open end of the 

 cocoon makes it a difficult matter to unwind the silk, and so it does not appear to 

 have a high commercial value, though it is said to have been successfully woven 

 into stockings. As the cocoon is three inches or more in length and nearlv an inch 

 and a half broad, one would expect that the extra quantity of silk would make 

 up for the defect. In California, however, a smaller member of the same family 

 is reared for the sake of its silk much as is the silkworm of the old world. The 

 cecropia-moth, as may be supposed from the dimensions of its cocoon, is a large 

 Insect. When the moth spreads its beautifully ornamented wings, the distance 

 between the tips of the fore-wings is about six inches ; and the caterpillar that 

 spins the big cocoon is four inches long and nearly an inch in thickness. It is 



1 riatjsamiii cecropia. 



