24 THE BUTTERFLY FARM AT THE ZOO 
that the Indian silk-moth has its native home. In 
the boundless upland forests, the trees on which it 
feeds are covered with thousands of the cocoons, 
which are gathered by these wild tribes, and sold to 
the silk-winders of the plains. Numbers of these 
fine cocoons line the cases at the Zoo, each with 
living pupa inside. The cocoons are beautiful objects 
in themselves, nearly the size of a walnut in the rind, 
and hanging by stalks firmly twisted to the supporting 
twigs, like rows of melons. Their colour varies 
through all shades of silvery or purplish-grey, streaked 
all over, like the eggs of the yellow-hammer, with 
fine irregular dark-purple lines. The silk threads of 
which they are woven are flat, like tape, not round, 
like the ordinary floss-silk of Europe ; and it is to 
this flat and irregular form of the thread that the 
beauty of woven tussur-silk is mainly due. It may 
be doubted whether the cultivation of the Tussur 
moth will spread to the West, like that of the 
common “ silkworm.” But the time is not far 
distant when this, and probably others of the fifty- 
nine species of silk-producing larvae which were 
exhibited in the Colonial and Indian Exhibition, will 
become an additional source of wealth in the wide 
forest-regions of our Indian Empire. 
The area of the jungle forest in the Santhal country, 
in which grow the trees whose leaves form the best 
food of these silkworms, is vast beyond any probable 
use which the most enterprising silk-grower conceives. 
“ As far as the eye could reach from any rising 
