198 AGRICULTURE AND FORESTRY. 



though the male cocoons almost always have a saddle-shaped de- 

 pression in the middle, and are smaller, but harder than the female. 

 The so-called double-cocoons, Jap. Tama-ito, French dotippions, are 

 suited neither for reeling-off nor for breeding. They originate from 

 two or even, possibly, three caterpillars choosing the same nook 

 and crossing and tangling their threads when spinning. They are 

 much larger and generally somewhat otherwise formed than the 

 simple normal ones. But their quantity of silk is less than it would 

 be if the caterpillars had spun themselves in separately. As a rule, 

 none of the enclosed pupae develops into a butterfly. They die 

 soon after their work in common. An attentive silk-raiser will 

 for these reasons seek to prevent the formation of double-cocoons 

 wherever he sees they are imminent, by inserting a splinter of 

 wood or a stiff piece of paper between the caterpillars. In Europe, 

 special apparatus have been devised for this purpose, " Appareil 

 cellulaire isolateur," etc., which were to be seen at the great in- 

 dustrial exhibitions in Paris. The pointed cocoons also {cocons 

 pomtiis) are hard to reel-off, and so are the very large loose ones 

 {cocalojis). Chaqtieites and cocons calcines also are of little value, 

 especially those in which the insect died before completing the 

 thread. Finally there are the cocons perces or pierced cocoons. To 

 this class belong first of all those from which the butterflies have 

 escaped. They dissolve the thread at one end of the cocoon's 

 long axis by means of a caustic liquid, and then make a hole 

 through. But we must add to these the cocoons which are pierced 

 by parasites — as in Japan by the larvae of the Uchi-fly ; for such 

 cocoons likewise cannot be wound off. They can only be worked 

 into floret-silk, like double-cocoons and the bourre. 



Seventeen or eighteen days after the caterpillars began to 

 spin, the butterflies (Jap. Chocho) creep out of their cocoons, at 

 about 8 a.m. They have broken through at one end of the long 

 axis by means of a corrosive liquid, and now sit just outside, with 

 their heads turned upward. The unmistakable marks of the females, 

 are greater size, a thicker body behind, plain antennae, and ex- 

 treme inertness, while the males or cocks are characterized by the 

 vigorous flapping of their wings. Pairing begins immediately, and 

 is over in 6 to 8 hours, whereupon the males are thrown away, and 

 the females set for laying their 250-400 eggs on the cards arranged 

 for that purpose. Within 24 hours they have performed this task, 

 and are now also cast aside as of no further use. 



The round eggs or graines, which at first are straw-colour, be- 

 come a slaty-grey within a fortnight, their fructification being 

 indicated by the change As already mentioned, they are wrapped 

 in paper and put into a dry, cool room, to be kept till the 

 next breeding-time in the following spring ; or they are sold to 

 Italian and French dealers for breeding in Europe, of which details 

 are given further on. In view of the small part played by the 

 Bivoltini (Natsu-go, or summer children) in Japanese silk-cul- 



