220 THE INSECT WORLD. 



francs, and even more. The value of manufactured silks represents 

 annually about 8,000,000 francs ; and we find by official statistic; 

 that France exported in 1863 silk stuffs to the value of 384,000,00c 

 francs. This immense trade shows how much silk is now-a-day< 

 everywhere appreciated ; in those numerous tissues called taffeta 

 satin, and velvet, each of which seems to have a charm — a peculiai 

 attraction. The consistency of the stuff, the smoothness, the softnes! 

 of surface, the manner in which silk receives colours, the brightness 

 fineness, power of reflecting, the rustling, the light or heavy folds,— 

 all these are beauty, elegance, and luxury, in whatever way thesi 

 words are understood. 



The Bojiibyx mo7'i has, however, nothing alluring in its appear 

 ance. Other caterpillars of the genus Bombyx have brilliant liveries 

 they are adorned with spots, blue as sapphires, green as emeralds, re( 

 as rubies, but produce threads without brightness and fineness. Th 

 humble silkworm, in a white blouse, like a workman, has nothins 

 brilliant in its dress, and yet it gives to the whole world its mos 

 beautiful and gorgeous array. The body of the silkworm is compose' 

 of thirteen distinct segments. In front are three pairs of articulate- 

 legs, which will become later those of the moth. In the middle an' 

 towards the posterior part, are five pairs of membranous legs, furnishe 

 with a circle of very fine bristles, which assist the animal to hoc 

 itself on to leaves and stalks. On the two sides of its body ar 



een stigmata, or respiratory mouths. 

 ^ The head of the silkworm is remarkable ; it is scaly, horny, an 

 fomied of one single piece. The mouth is provided with six sma 

 articulated pieces. Below is a simple blade, the upper lip, having i 

 its middle a hollow, into which the animal causes the edge of tb 

 leaf it is gnawing to enter, and holds it thus without any exertioi 

 Underneath the lip are inserted two large jaws, which cut the leaf < 

 a pair of scissors. Underneath, some weaker jaws divide tl' 

 fragments, and a little organ, articulated on to each jaw, that is 1, 

 say, a palpus, pushes them back towards the mouth, and prevents til 

 smallest particle of the leaf from falling. And lastly, in the spa( 

 comprised between the two jaws, is an under-lip, which complete 

 closes the mouth below. At the extremity of this piece may be set 

 a little prolongation, a sort of papilla, pierced with a hole, which 

 the orifice that gives issue to the silky thread. 



The organs which serve for the elaboration and emission of t] 

 silk have a peculiar interest for us. If we dissect a silkworm und 

 water, we succeed, sooner or later, after having removed the out 

 parts, in laying bare a double apparatus, placed along the two sid 



Wght 



