Interesting as is the whole subject of bird and insect manufactures, there is one department in which we are more concerned than the rest; namely, that in which the product can be applied to our own use, either in the way of food or clothing. Now this department is supplied wholly by insects, no bird, that we are aware of, producing by its own manufacturing powers, any substance that can be so employed, unless, indeed, we except the curious edible nests of the Java swallow, which have been converted by the taste of oriental epicures into an article of food.
Let us then proceed to notice such of the insect manufactures as are useful to man, and trace, at the same time, the history and performances of these small but not insignificant manufacturers.
CHAPTER I.
MANUFACTURE OF SILK BY CATERPILLARS OF VARIOUS KINDS.
The most important of all the insect manufactures is doubtless that of silk-spinning. It seems almost past belief that the magnificent velvets, satins, and silks which form so elegant a part of female attire, and which are heaped together in such costly profusion in the shops of the metropolis, and in those of all considerable towns, whether in our own, or in foreign countries—that these splendid fabrics, together with all ribbons, gauzes, damasks, or other articles composed of silk, should owe the raw material of which they are formed to the labours of a race of little creeping caterpillars, which in this their early and imperfect state spin for themselves cocoons, or cases of silk, where they may quietly undergo their changes until they become perfect winged insects.
CATERPILLAR SUSPENDED BY ITS SILKEN THREAD.
The astonishing task of supplying silk for the whole civilized world is performed almost without exception by the common silkworm, or caterpillar of the mulberry-tree moth. But it must not be supposed that this is the only silk-producing insect. On the contrary, all the caterpillars of butterflies and moths have the power of spinning a certain quantity of silken thread, however small, and however inferior to that of the silkworm, properly so called. It is very common in gardens to see numbers of caterpillars dangling by their silken threads from the young branches of fruit-trees. In this way they let themselves down, or break their fall if blown off by the wind, or otherwise shaken from their favourite tree. And in the case of some caterpillars when the insect has completed the term of its existence and becomes a chrysalis, it suspends itself by silken cords to some fixed point, where it remains in complete repose, without food, perhaps for months before the perfect winged insect bursts forth, as different a creature from the caterpillar as the chrysalis is from either,—and yet these are but three different states of existence of the same insect.
CHRYSALIS SUSPENDED BY SILKEN CORDS.