200 THE LIFE OF AN INSECT. 



until it has woven around itself an envelope, as it 

 were, of loose gauze. After this has been done 

 it begins to form the closer and more compact 

 structure of the inner envelope, laying on the silk 

 backwards and forwards in a series of zig-zags, 

 until it has laid on several layers, and thus com- 

 pletely shut itself in. The loose outer portion 

 forms what ladies so well know under the title 

 of flos-silk; the inner fibres are the most con- 

 tinuous, admitting of being wound off without 

 breaking, and they form the ordinary silk of 

 commerce. 



M. Lyonnet has given a most interesting account 

 of the proceedings of another larva which far sur- 

 passes the silk-worm in the ingenuity of its man- 

 ner of forming the cocoon. This larva is very 

 small ; in fact, not more than the sixth of an inch 

 in length, and is found on the under side of oak- 

 leaves. M. Lyonnet observes, that beyond all 

 the larvse he had ever watched, he considered this 

 creature the most inconceivably ingenious work- 

 man. Its little cocoon is of a white colour, and of 

 a long oval form, having its upper surface orna- 

 mented with seven upright ridges. The first 

 thing the creature begins by doing, is to erect, in 



