THE BUTTERFLY FARM AT THE ZOO 25 
ground,” writes Mr. Thomas Wardle, in his History 
of the Growth of the Tussur Silk Industry , “and for 
hundreds of square miles, there lay a forest in which 
it seemed that any quantity of the tussur of the 
future might be cultivated, and I think it is worthy 
of the attention of the Government of India to 
encourage in every way a greatly increased production, 
and not to be behind China in this respect, remember- 
ing that when I showed how 7 tussur-silk could be 
used, the demand which sprang up was chiefly met 
by the greater quickness of the Chinese.” 
Not only the moths, but even the caterpillars, or 
larvae of the various silk-moths, are as beautiful as 
any fabric which is w r oven from the glossy fibres of 
their cocoons. Let no one despise “ worms and creep- 
ing things” after once seeing these exquisitely formed 
and coloured creatures. The larvae of most may be 
seen in late July in the Insect House, feeding on 
green leaves in the cases. The finest are those of 
the Cecropian silk-moth ; they are of a blue-green, 
with a soft bloom like that on some succulent plant. 
The whole body is clothed with alternate lines of 
turquoise and amber studs, specked with black, 
polished and shining like jewels. Those that have 
spun their cocoons are wrapped in jackets of light- 
brown silk, into which strips of green leaves of the 
plum-tree are twisted for protection. The Ailanthus 
silk-moth has a pale-grey larva, with little ornaments 
in rows, shaped like the flowers of the stone-crop, 
and dotted with black. The moth itself is strangely 
