LEPIDOPTERA. 239 
g long time. They must, in other words, kill the chrysalides, 
\to prevent the cocoons being pierced by the moth. To kill the 
j chrysalides so as to prevent the development of the imago 18 
} an operation which is called the étouffage, or stifling. 
| To effect this stifling, the co- ; 
| coons are exposed to a high tem- 
perature. Formerly, in the Cé- 
-vennes, the cocoons were placed 
in a baker’s oven, heated for bak- 
ing bread. But they ran the risk 
thus of being burnt, or of a certain 
number of chrysalides remaining 
alive. Now, to kill the chrysalides, 
they make use of steam at LOOS 
produced by water boiling in a 
| vessel, and which passes through 
wicker baskets filled with cocoons. 
The rearer must also take care 
at the time he gathers them, to 
separate the cocoons which are 
to provide eggs for the next year. 
As the females are heavier than 
| the male cocoons, they easily sort Fig. 217.—Apparatus for stifling the 
_ them with a pair of scales. ee eee Gy 
| To obtain the eggs or grain, the cocoons are fixed on sheets 
of brown paper, covered with a slight coating of paste made 
of flour. They are arranged in such a manner that the moths 
shall find no obstacle when they come out of them, head fore- 
most; and, on the other hand, that they may be able to reach 
with their legs the cocoon which is opposite them, so as to 
hang on to it, and to facilitate their exit from their own cocoon 
(Fig. 218). The meal and female cocoons are pasted on separate 
sheets. 
It is from fifteen to twenty days after the montée or mounting, 
and when the temperature of the rooms has been kept between 
20° and 25°, that the moths begin to be hatched. As they appear, 
| they are seized by their wings and placed on cloths stretched out 






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