of the cultivation of this large species are manifest: the silk is coarser; their life being four or five days longer, the labourers must be kept longer; the expense and the risks are therefore greater; and the accidents attending the mulberry-tree will also be thereby multiplied. It has been stated, that 39,168 eggs of the common silkworm weigh an ounce. If each egg produced a worm, and each worm came to maturity, an ounce of eggs should yield 162 lbs. of cocoon. This is in conformity with Count Dandolo's experience, under his improved mode of rearing the silkworm. Latreille, however, gives a very different result. Formerly, he says, an ounce of eggs produced 80 or 100 lbs. of cocoon, ten or at most twelve pounds of cocoon yielding a pound of silk. But for some time the ounce of eggs has scarcely yielded thirty or forty pounds of cocoon, and fifteen or sixteen pounds of cocoon yields but a pound of silk. This difference he attributes to the injudicious selection of eggs. A perfect egg or grain, as it is termed, should be of a dark slate-colour. There are different modes adopted to hatch them. In the south of France they are enclosed in cotton, and carried by the women between their petticoat and chemise during the day, and at night placed in the same bed with them. The spontaneous hatching of eggs by means of the natural heat of the atmosphere, is of course out of the question in climates as variable as those of Europe. During the hatching of the eggs, the temperature of the stove-room in which the worms are to be developed should be at least 64°, and this should be gradually increased up to 75°, in which degree of warmth the young worm is to be kept until the first cast or moulting. The heat during the second cast should be between 73° and 75°, between 71° and 73° till the third, and lastly, between 68° and 71° till the fourth. The extent of space which should be occupied by the silkworms in their different ages is no less essential than the due regulation of temperature to their development; an ounce of eggs should have a space, In the first age, of 7 feet 4 inches square; In the second age, of 14 feet 8 inches square; The food which they consume should be no less accurately determined; and great care must be taken in picking and sorting the leaves for the feeding of the worms of the first ages, such as picking off all the twigs, the stalks of the leaves, spots, &c., and to clear them as much as possible from all useless parts. This operation is most essential in the two first ages, when the leaves are to be chopped very small. In the third age, the sorting and picking the leaves is not of much consequence, and still less so in the fourth and fifth ages. The sorting and picking is of importance, inasmuch as it enables you to put fifteen or twenty per cent. less substance upon the wickers than would otherwise be done, and which the worms would not eat. This substance increases the litter and the moisture, without necessity or motive. In climates where they are in the open air, it would, of course, be unnecessary to sort the leaves. In the fifth, and even in the fourth age, when the season is favourable, leaves, mixed with a quantity of mulberries, boughs and stalks, may be put on the hurdles, although it is known that the worms do not eat them, because at that period it would be too troublesome to sort so large a quantity perfectly, nor is there the same motive to do so. These substances being by this time grown large, hard, and woody, are less liable to fermentation, although they may accumulate as litter. If the laboratories are kept constantly dry and well aired, these substances will do no mischief, but keep the litter light, and allow the air to circulate more freely through it. When the silkworms find any leaves that they do not like, they leave them. There are some of a dark hazel colour, which have fermented slightly; these the worms will eat, if they are not quite spoiled, nor are they the worse for it; from which fact it would appear that the fermentation has not affected the saccharine or resinous part of the leaf. The quantity of leaves, according to Dandolo, taken from the tree, and employed for each ounce of eggs, amounts to 1609 lbs. 8 oz., divided in the following manner: But this leaf has lost by sorting much of its weight, in the following proportion: With these precautions, it is found that in thirtynine days the worm becomes 9500 times heavier, while in twenty-eight days it is increased forty times in length. In the last twenty-eight days of its existence, viz., from the period of its greatest development as a caterpillar until its death as a moth, it gradually diminishes in length a fifth, and in weight about thirty times. CHAPTER VI. NATURAL HISTORY OF INDIAN MOTHS AND OTHERS REARED FOR THEIR SILK. Tusseh Silkworm, its Metamorphoses, its Flight, Manner of winding the Silk-Jarroo Silkworm, their Habits-Arrindy or Arundi Silkworm, Manner of Rearing, its Metamorphoses, its Silk, Manner of Spinning-The Manner of Manufacturing the Silk of Tinea punctata-Account of the Silk of an indigenous American Moth-History of preparing Silk from Spiders, Kinds of, Manner of Spinning, Number of Spiders, Eggs, Quantity of Silk, Weight of the Bags. DR. ROXBURGH informs us that the East Indians possess three or four species of moths, from the cocoons of which they have been in the habit of spinning coarse kinds of silk. The first is termed the Tusseh silkworm, or Bughy, of the natives of the Burbhoom Hills (Phalana paphia), which seems to have been employed VOL. II.-K from time immemorial, and is found in such abundance over many parts of Bengal and the adjoining provinces, as to have afforded to the natives a plentiful supply of a most durable, coarse, dark-coloured silk, which is woven into a kind of cloth called Tusseh doothies, much worn by the Brahmins and other classes of Hindoos. This silkworm cannot be reared as the common one; the natives therefore go out in quest of them into the jungles, and find the young worms on the branches of the asseen and byers trees, which the natives cut off, and convey near their habitations, distributing the worms on the asseen in proportion to the size of the trees, but they place more on the byers, and employ the Pariahs to guard them day and night, to preserve them from birds and bats. The eggs of this species are white, and are hatched according to the temperature of the air; in two or three weeks, however, the worms have nearly acquired their full size, which is above four inches in length and three in circumference; their colours are light green, with a light yellowish-coloured stripe on each side; the sixth and seventh rings are marked with an oblong gold spot; the back is also marked with a few round darker col |