VOL. L3CXIX.] ^ PHILOSOPHICAL TRANSACTIONS. 555 



it into shell lac, in which state much of it is received from Assam, and exported 

 to Europe for various great and useful purposes. The tree on which this fly most 

 commonly generates is known in Bengal by the name of the Biher tree, and is a 

 species of the rhamnus. The fly is nourished by the tree, and there deposits its 

 eggs, which nature has provided it with the means of defending from external 

 injury by a collection of this lac, evidently serving the twofold purpose of a 

 nidus and covering to the ovum and insect in its first stage, and food for the 

 maggot in its more advanced state. The lac is formed into complete cells, 

 finished with as much regularity and art as a honey-comb, but differently ar- 

 ranged. The flies are invited to deposit their eggs on the branches of the tree, 

 by besmearing them with some of the fresh lac steeped in water, which attracts 

 the fly, and gives a better and larger crop. The lac is collected twice a year, in 

 the months of February and August. 



I have examined the ^^^ of the fly with a very good microscope; it is of a 

 very pure red, perfectly transparent, except in the centre, where are evident 

 marks of the embryo forming, and opaque ramifications passing off' from the 

 body of it. The egg is perfectly oval, and about the size-of an ant's e.gg. The 

 maggot is about the 8th of an inch long, formed of 10 or 12 rings, with a small 

 red head; when seen with a microscope, the parts of the head were easily dis- 

 tinguished, with 6 small specks on the breast, somewhat projecting, which 

 seemed to be the incipient formation of the feet. This maggot is now in my 

 custody, in the form of a nymph or crysalis, its annular coat forming a strong 

 covering, from which it should issue forth a fly. I have never seen the fly, and 

 cannot therefore describe it more fully, or determine its genus and species. I am 

 promised a drawing of the insect in its different stages, and shall be able soon to 

 add to a botanical description of the plant, a drav^ing of the branch, with the 

 different parts of fructification and lac on it. The gentleman to whom I owe 

 part of my information terms the lac the excrement of the insect. On a more 

 minute investigation however, we may not find it more so than the wax or honey 

 of the bee, or silk of the silk-worm. Nature has provided most insects with 

 the means of secreting a substance which generally answers the twofold purpose 

 of defending the embryo, and supplying nourishment to the insect from the 

 time of its animation till able to wander abroad in quest of food. The fresh lac 

 contains within its cells a liquid, sweetish to the taste, and of a fine red colour, 

 miscible in water. The natives of Assam use it as a dye, and cotton dipped in 

 this liquid makes afterwards a very good red ink. 



The simple operation of purifying lac is practised as follows. It is broken 

 into small pieces, and picked from the branches and sticks, when it is put into a 

 sort of canvas bag of about 4 feet long, and not above 6 inches in circumference. 

 Two of these bags are in constant use, and each of them held by 2 men. The 



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