52 
Hlementary Manual of Zoology. 
which shelter themselves during their pupal stage in cocoons made of 
large quantities of silk, which can be utilised for commercial purposes. 
The only forms with which the students need be acquainted are, 
the domesticated Mulberry silk-worm, the domesticated Eri silk-worm, 
and the semi-domesticated Zusser and Muga silk-worms. They should 
notice, however, that there are many wild silk-worms in India which 
would be useful if they were forthcoming in larger quantities than is 
now the ‘case. : 
An account of thestructure of the mulberry silk-worm (Bombyx 
mori) is givenin the chapter on the dissection of this insect. The 
imago is an insignificant-looking white moth, with rudimentary mouth 
parts. Several varieties are cultivated in the plains of Bengal upon 
mulberry leaves. Most of them differ fiom the mulkerry silk-worm of 
Europe in being smaller in size and in passing through a number of 
generations in the year. The large annual variety of Europe, however, 
is cultivated in Kashmir and elsewhere in the hills. Mulberry silk- 
worms yield a large amcunt of valuable silk in India, butare of little 
importance to the forester, The students should notice that they 
suffer from the attack of Tachinid flies, and are subject to pebrine 
Jlacherte and cther diseases which likewise attack the Europcan 
variety. 
The Eri silk- worm (4étacus ricint, Boisd.) is somewhat larger than 
the mulberry silk-worm. It is reared ina state of domestication 
upon castor-oil leaves in Assam, much in the way that the mulberry 
silk-worm is reared in Bengal. It passes through a number of gener- 
ations in the year, and produces a coarse but useful silk known as 
Assam silk. The moth is a large dark-coloured insect, which may be 
recognised by its peculiar shape and markings, Eri silk-worms suffer 
to some extent from the same diseases and parasites as the mulberry 
silk-worm. 
© 
From a forester’s point of view the most important silk insects are 
the Tusser and the Muga, The Tusser silk-worm (Antherea mylitta 
ov A. paphia) is a brilliant green caterpillar, adorned with numerous 
tubercles. ‘The imago is a large yellow or buff-coloured moth, which 
can be recognised by its shape and by the curious transparent ocelli 
with which its wings are furnished. The cocoon is a firm structure 
which is attached to the food plant by a silken stalk of singular 
strength and neatness, The insect is reared in the jungles of the 
Central Provinces, Chita Nagpur, and elsewhere throughout the 
Central and Southern parts of India. The caterpillars feed on the leaves 
of saj (Terminaiza tomentosa), sil (Shorea robusta) and ber (Zizyphus 
jujuba), and other furest trees. The inseet hybernates in the cocoon, 
The moths of the first generation emerge in the early part of the 
rains, and lay eggs which usually produce cocoons about the middle of 
