NATURAL PRODUCTS OP THE COGGIDM. 17 



product known as " lac," which forms a basis for varn- 

 ish, French polish, and many other equally important 

 materials. It is usually imported into this country 

 upon the twigs or small branches of the trees upon 

 which the insects have secreted it, and is known com- 

 mercially as " stick lac," which after treatment is made 

 into " cake lac," and finally into " shell lac," a material 

 known to almost every schoolboy. Being of such value 

 to us, I have ventured to give a photograph of examples 

 of the " stick lac " (PI. A, fig. 1), the history of which 

 may be briefly described as follows : 



" Like all other Coccids, the young (larvae) are active ; 

 they are at first very tiny creatures, resembling mites, 

 and are generally spoken of by the horticulturist as 

 6 lice.' These young arrange themselves in groups of 

 various dimensions round the twigs of the food-plant, 

 and, having settled matters satisfactorily as to space, 

 insert their thread-like sucking-tube (mouth) into the 

 plant tissues, and pump up the sap of the tree. At 

 the same time they commence covering their bodies 

 with the peculiar ' lac ' which, by the time they are 

 fully developed adult females, assumes the form and 

 size shown in the illustration. By taking a hot knife 

 a transverse section of the material may easily be 

 made, when it will be seen that the covering material 

 or ' lac ' is not a solid mass, but is honeycombed by 

 large, somewhat ellipsoidal cells, each of which was 

 once tenanted by a single female If we exa- 

 mine a female we find she is shaped somewhat like the 

 cavity in which she lives, with the cephalic portion 

 bearing the mouth parts touching the bark at the 

 narrow end of the cavity, and the abdominal extremity 

 at the opposite end having connection with the exterior 

 by means of a minute perforation ; and she is desti- 

 tute of legs and antennae, etc. Where she has lived 

 she dies, leaving as a legacy the wonderful product 

 which she manufactured during life, and which all the 

 world over is of so great importance in commerce. 

 And this is not all; the bodies of the females also 



2 



