236 THE INSECT WORLD. 
the very beginning of the rearing, and increases in intensity at 
each age, so that the number a worms able to enter regularly 
into Bite moult becomes smaller and smaller. We are still ina 
state of utter 1gnorance as to the cause of this last affection, 
which has occasioned, for the last ten years, incalculable losses in _ 
the rearing houses, which threatens the silkworm with complete 
destruction, and which in the meanwhile has ruined the unfortu- 
nate countries of the Cévennes, the principal seat of sericiculture 
in France. 
During the fifth age, the worms become large so quickly that 
on the fifth or sixth day they are obliged to be moved away from 
each other on the litter. The délitement must be made every two 
days, or, indeed, every day now, on account of the enormous 
amount of the excrement; and, at the same time, a good venti- 
lation must be constantly maintained. ‘The temperature of the 
room should now be kept to 24°, without ever exceeding this 
degree of heat. When it is perceived that the worms wish to 
ascend, or mount, there are placed on the tables, at certain distances 
from each other, little sprigs of heather or very dry branches of 
heht wood. 
When the worms begin to mount into the heather, one must 
encabaner—that is to say, form with these branches little hedges, 


omen i FEE mi i 
Fig. 213.—Sprigs of heather arranged so that the Silkworms may mount into them. 
eurved back like a hut or cradle, the openings of which are, 
on an average, seventeen inches or so (Fig. 213). At the 
expiration of twenty-four hours, all the good worms have 
mounted. The laggards who remain under the cabanes are 
taken off by hand, and placed on a table, which is tome 
-encabaned. 
