352 
MOTH. 
injures them so much as moisture and impurity. 
In order to preserve the silkworms from the distem- 
pers to which they are liable, the persons who 
have the care of them are attentive to gather their 
leaves in a dry season, and preserve them in a place 
where no moisture can come, as wet is exceedingly 
prejudicial to the caterpillars, and drying the leaves 
takes up more time than the young nursery can 
well spare, as they come into the world with a de- 
termination to make the best use of the short period 
allowed them, and are therefore always feeding 
most voraciously till they prepare to pass into the 
chrysalis state. Leaves of lettuce or holly-oak are 
occasionally given them when the mulberry leaves 
happen to fail, but they have little relish for this 
food ; they only submit to it from necessity, and the 
silk they then spin is of an inferior quality. Fresh 
air must be admitted into the room from time to 
time, as upon that and cleanliness the welfare of 
the silkworms greatly depends. 
Having thus described the manner in which 
these useful insects are reared, we shall proceed 
to trace them through the different stages of their 
growth. 
We have already noticed that when the silkworm 
first leaves the egg it is extremely small, and perfectly 
black. In a few days it begins to assume a whitish 
hue, or rather an ash gray, and in about a week after 
its birth it has grown to the length of a quarter of an 
inch, soon after which it suffers a temporary lethar- 
gy, and sleeps for two or three days: towards the 
expiration of this time, the little animal becomes 
