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 seements. 
In front, are three pairs of articulated legs, which will become 
later those of the moth. In the middle and towards the poste- 
rior 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 trunk, articulated 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 com- 
prised 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 
silk have a peculiar interest for us. If one dissects a silkworm 
under water, one succeeds very soon, after having separated it 
from the other 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 seri- 
cipary gland. Lach 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 BOC, 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 
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