HemipterA. 137 



lines. The bodies of many fecundated females, united together by a 

 resinous exudation which is caused by the piercing of the bark, 

 constitutes the matter called in commerce and by dyers by the name 

 of Lac Dye, Shell-lac, Gum-lac, &c. 



Resinous lac is found in commerce under four forms : — First, the 

 stick-lac, such as it is found concreted at the extremity of the 

 branches whence it exudes — it is an irregular brownish crust; 

 secondly, the seed-lac, picked off the branches and pounded; 

 thirdly, shell-lac in scales melted down and run into thin plates, 

 which vary in quality according to the proportion of colouring matter 

 they contain ; fourthly, thread-lac, which resembles reddish threads, 

 and is prepared thus in India. 



One more word about the cochineal. The Coccus mamiiparus^ 

 which lives on the shrubs {Tamarix mannifera) on Mount Sinai, 

 causes to exude from the branches it has pierced a sort of manna. 

 The Coccus sinensis produces a kind of wax which is employed in 

 China in the manufacture of candles. 



62* 



