260 



UTILITARIAN ZOOLOGY 



may be traced, and to France and Italy, in particular, it is now 

 of great importance. In the former country about 137,500 cwts. 

 of raw silk (worth "1,080,000) is produced annually, while the 

 Italian yield in 1902 was 823,718 cwts. (worth ^2,355,057). 



Of late years the Chinese have engaged in the culture of the 

 Oak Silk- Moth (Saturnia Pernyi\ of which the larvae feed on 

 oak-leaves. The silk is coarser and less valuable than the 

 ordinary kind, but possesses the merit of greater strength. An 

 allied species (S. yama-mai) is cultivated in Japan. 



H o w far 

 silk is im- 

 portant to 

 Britain may 

 be gathered 

 from the fact 

 that in 1902 we im- 

 ported 1,252,848 Ibs. 

 of raw silk worth 

 "728,020, and silk 

 goods to the value 

 of 14,321,541. 



THE COCHINEAL 

 INSECT ( Coccus 

 CACTI, fig. 1190). 

 The colouring - 

 matter known as cochineal, as also (to some extent) the pig- 

 ments known as carmine and lake, are derived from a species 

 of bug native to Mexico, which feeds upon the Nopal (Opuntia 

 coccinellifera], a plant of the cactus sort. The culture of this 

 insect dates back to the times of the ancient Mexicans, and is now 

 of some importance in Central America. The insect and its food- 

 plant have also been successfully introduced into the Canary 

 Islands, Algeria, Java, and Australia. The colouring -matter is 

 obtained from the dried bodies of the female insects, which are 

 ground and extracted. It requires about 70,000 of them to 

 produce a pound of cochineal. The introduction of cheap aniline 

 dyes has caused this industry to decline, while carmine and lake 

 can now be manufactured chemically. 



Fig. 1190. Nopal (Opuntia cocdnellifera) and Cochineal Insects (Coccus 

 cacti], enlarged, female to left, male to right 



