io8 
TRANSFORMATIONS OF INSECTS. 
is celebrated for containing the Bombyx mori — the mulberry cater- 
pillar or silkworm. This genus Bombyx has been sub-divided, 
so that now this well-known pet amongst children, and great care 
amongst silk growers, is called Sericaria. 
This insect is so well known that no description of its rapidly- 
growing caterpillar, the lazy chrysalis, and the quiet moth that 
never eats or sucks, is necessary. What a plain, ugly moth it 
is, and what a common looking grub comes from the egg. 
There is nothing charming, no bright tints, and no delicate 
ornamentation ; moreover, it is rather clumsy looking. None 
of the graces of form or the magnificence of the colouring 
of the Lepidoptera that enliven the shades of the grandest 
flowers are here. The caterpillars of some species of the 
genus are even handsome, and have pretty green globular 
ornaments on their segments, and others like coral and pearl ; 
but the humble silkworm has none of these. Its beauties are 
intrinsic, and it yields the most beautiful web that Nature can 
produce, to render, if possible, the loveliest of all created things 
more attractive than ever. The comparison of the silkworm 
caterpillar with those of other moths soon enables us to dis- 
tinguish between the Sphingidoe and the Bombycidoe , and to 
notice how much they are alike in structure generally speaking. 
The silkworm caterpillar resembles those of some sphinges in 
its shape, and in its having the tubercle on the last segment 
but one of the body, but it differs from all by having its silk- 
bearing glands enormously developed. When a full-grown silk- 
worm caterpillar is opened, the intestinal canal will be seen to 
fill the greater part of the body, and on either side of the stomach 
and gullet there will be observed a large twisted tubular gland. 
This is the silk gland, or rather, of that viscous matter, which 
as it is drawn out, hardens into silk. These glands pass under- 
neath the gullet, and each is continued in the form of a narrow 
tube to the mouth ; they unite before reaching the head, and 
form one canal, into which open the ducts of two little glands, 
whose function is to unite the silken threads of the silk tubes, 
to varnish and brighten them, and to give them that perfection 
of texture we all admire and value. The canal opens in the 
lower lip or labrum, and passes through a small opening in a 
