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 manniparus, 

 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. 



