CLASS I. INSECTA: ORDEK 4. LEPIDOPTERA. 575 
for though 
it possesses no weapons, and the bees are well armed, they never appear to attack 
the intruder. This species is com- 
mon in Europe. 
The Lime-Tree Sphinx, Sphinx 
tilice, has the wings denticulated and 
angular; it is nocturnal, and flies 
heavily. It is common upon elms, 
horse-chestnuts, and especially limes, 
where the caterpillars of the species 
abide. 
A considerable group of insects 
belonging to this tribe have trans- 
parent wings. Among them is the 
Humming-bird Moth, Sesia pelas- 
gus, often seen at evening in our 
gardens during the months of June 
and July, hovering like a humming- 
bird over the flowers and sucking 
THE LIME-TREE SPHINX. tlicir Hcctar wlth its long tube. 
THE PSYCHID^. 
This is a family of small moths, the larvse of which form portable cases for their protection, in 
which they undergo their transformations. 
THE BOMBYCINA. 
This includes some of the largest species 
of the order, and among them the Silk- 
worm Moth, Bomhyx mori. This import- 
ant insect is a native of the north of China; 
and a great portion of the supplies of silk 
for Europe and America are still derived 
from that country. It was introduced into 
the south of Europe in the sixth century of 
the Christian era, when some of the eggs 
were brought to Constantinople, whence- 
the insects have gradually spread into Italy 
and France — in both which countries the 
cultivation of the silk-worm is an import- 
ant branch of industry. "When the insect 
is full grown it quits its food, and betakes 
itself to some convenient spot, where, after spinning a few threads in various directions, it sus- 
pends itself in the midst of them ; and by continually twisting its body, it gradually envelops 
itself in a thick silken cocoon. By reeling this carefully off, a delicate unbroken thread, some- 
times exceeding one thousand one hundred feet in length, is obtained. The silk-worm is usually 
fed upon the white mulberry, Morus muUicaulis, though it will eat lettuce and the leaves of the 
maple, oak, pear, and apple-tree. They are easily cultivated, and the raising of silk received a 
great deal of attention in this country a few years ago. But labor is so much cheaper in China, 
Italy, Fra;ice, and other countries, that silk can be produced there at less cost than in the United 
States. This pursuit is, therefore, nearly abandoned. The value of all the silk produced annually 
throughout the world amounts to hundreds of millions of dollars. 
The Arrindt Silk-Worm of India, £. Cynthia, furnishes a silk Avhich is said to possess aston- 
ishing durability. The caterpillar feeds upon the castor-oil plant, and has recently been introduced 
THE HUMMING-BIRD MOTH. 
