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 Zo, 855 057); 
Of late years the Chinese have engaged in the culture of the 
Oak Silk-Moth (Saturnia Pernyt), of which the larve 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-maz) is cultivated in Japan. 
How far 
silk is  im- 
portant to 
Britain may 
be gathered 
from the fact 
that in 1902 we im- 
ported 1,252,848 lbs. 
of raw. silk worth 
4728,020, and silk 
goods to the value 
of £14,321,541. 
THe CocHINEAL 
INSECT ( Coccus 
Fig. r190.—Nopal (Opuntia coccinellifera\) and Cochineal Insects (Coccus CACTI, fig. II go). 
cact), enlarged, female to left, male to right 
—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 (Opuzn/za 
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. 
