LEPIDOPTERA. 223 
_ liveries; they are adorned with spots, blue as sapphires, green 
as emeralds, red as rubies, but produce threads without bright- 
ness and fineness. The humble silkworm, in a white blouse, like 
a workman, has nothing brilliant in its dress, and yet it gives 
to the whole world its most beautiful and gorgeous array. The 
body of the silkworm is composed of thirteen distinct segments. 
In front are three pairs of articulated legs, which will become 
later those of the moth. In the middle and towards the posterior 
part, are five pairs of membranous legs, furnished with a circle 
of very fine bristles, which assist the animal to hook itself on to 
leaves and stalks. On the two sides of its body are eighteen 
stigmata, or respiratory mouths. 
The silkworm is remarkable for its muzzle. This is scaly, 
horny, and formed of one single piece. The mouth is provided 
with six small articulated pieces. Below is a simple blade, the 
upper lip, having in its middle a hollow, into which the animal 
causes the edge of the leaf it is gnawing to enter, and holds it 
thus without any exertion. Underneath the lip are inserted two 
large jaws, which cut the leaf as a pair of scissors. Underneath, 
some weaker jaws divide the fragments, and a little organ, articu- 
lated on to each jaw, that is to say, a palpus, pushes them back 
towards the mouth, and prevents the smallest particles of the leaf 
from falling. And lastly, in the space comprised between the two 
jaws, is an under-lip, which completely closes the mouth below. 
At the extremity of this piece may be seen a little prolongation, 
a sort of papilla, pierced with a hole, which is the orifice which 
gives issue to the silky thread. 
The organs which serve for the elaboration and emission of the 
suk have a peculiar interest for us. If one dissects a silkworm _ 
under water, one succeeds very soon, after having removed the 
outer parts, in laying bare a double apparatus, placed along 
the two sides of the intestinal canal and below it. This is the 
apparatus which secretes the silk; it is the double sericipary 
_ gland. Each one of these glands is composed of a tube formed of 
three distinct parts (Fig. 201). The part which is nearest to the 
tail of the worm is a sort of bent tube, A B C, of a thirtieth of 
an inch in diameter, and about nine inches in length, twisted a 
great many times into irregular zigzags. This part of the silk- 
