D.—No. 3

10

PAPERS RESPECTING SERICULTURE

As Father Fantoni had told his friends that the Chinese fed them with the leaf of a tree something like an acacia, they tried the worms with the Ailanthus glandulosa leaves, which they discovered were eaten greedily. These worms multiplied, and some eggs were transmitted to France, where they are now becoming a great source of profit. op the eggs. The eggs of the Bombyx cynthia are twice as large as those of the common silkworm, and the females lay about half as many. They are oval, equally large at both ends, white, and marked with black, caused by the particles of gum inside them. One gramme of eggs of the Bombyx cynthia contains about 100 eggs. The quantity of eggs laid by the females is very variable, and is according to the size of tho moths. If they are in strong health, one will give from 200 to 400 eggs; but the right proportion would be about 250 to each. When the eggs are near hatching they flatten a little, and lose their weight, and assume a grayish tint, which is produced by the caterpillar inside. The caterpillars are hatched about eight or twelve days after the eggs are laid, according to the temperature. The most characteristic colour at this age is to appear black, but seen through a microscope they are yellow underneath. They have a transverse black mark all along their body. Like many other caterpillars, they change their skins four times, or go through four changes before they make their cocoons. Before each change they remain inactive from twenty-four to forty-eight hours, according to the temperature. Before this crisis arrives, they cover the under part of the leaf on which they are with an invisible gummy substance of threads of silk, and they fix so solidly their membraneous feet that the old skin remains adhering whilst they pass on. OP THE CATERPILLARS. The existence of these caterpillars, like those of tho mulberry silkworm, is divided into five stages. The first is the interval between their birth and the first change ; the second is that between the first and second change; the third is between the second and third ; the fourth, that from the third to the fourth; the fifth, that of the fourth change till the formation of the cocoon. The caterpillars have a different colour and shape in each of their stages. Thus, during the first, as I before said, they are yellow-coloured with a black spot down the belly, independently of black tubercles. During the second change their body is about 4to 5 tenths of an inch long. They are still yellow, with head tubercles and segments quite black. At the third crisis the caterpillar is from 6to 8 tenths long, and soon becomes quite white. At this stage there comes all over their body a waxy secretion, forming a sort of white flour, destined to protect the worm against rain and dew, as water cannot fix on it. At the fourth stage it attains the length of fto 1 inch. Its body is first white; then it becomes gradually green, with tubercles of the same colour; and soon the head, the feet, and the last segment become of a golden yellow. There are always black points upon the segments or rings of the body and tho floury secretion. At the fifth stage the emerald green colouring is the same, but more intense, and extremities of the tubercles become of a marine blue. The caterpillar is then from 1\ to 1^- inch long, but it grows rapidly, and, according to the abundance and quantity of the food, it attains the length of from 2f to 3 inches long. Arrived at this stage, it begins to eat less, and gradually becomes of a yellowish green. It begins the cocoon by fixing two or three leaflets firmly to the main stem with its silk, so that it may be secure at the fall of the leaf in the beginning of the winter. OF THE COCOON. In weaving its cocoon this wrorm does not proceed, like the mulberry silkworm, because it makes an elastic opening for the exit of the moth. In working, the caterpillar takes from time to time a little repose, but this only lasts a few seconds. From time to time also, after having placed a number of zigzags of thread, it stops and puffs itself out, as if to push out the sides and make the necessary room. When it works from the side of the opening it makes much longer movements, and places the thread in a longitudinal way, advancing it to the extremity of the opening, cementing one thread to another, and returning parallel to the first thread. During all this while its antenna? are at work, as well as its mandibles. These seem to serve as polishers, for they neither bite nor cut any part of the work. Tho threads that form the opening of these cocoons are not cut, but simply turned and laid one over another. The cocoons of the ailanthus worm are of an elongated form, of more or less pale and gray colour, of very close tissue, 1_- to If inch long, and about f broad. They vary much in size and weight, according to the conditions in which they were obtained. OE THE SILK. These cocoons naturally open like those of the mulberry silkworm after the exit of the moth, but up to the present time they cannot be spun off in a continuous thread; therefore, they have as yet only yielded floss, and, consequently, the fibre is more or less short, so that they have only been spun like wool or cotton. The difficulty does not arise because the thread is cut at the opening made for the exit of the moth, as some people have imagined, because the threads are not cut, but only laid one over another. It results only from the circumstance that the cocoon, being open at one end, fills with water (when placed in the basin), and being so heavy breaks the thread; but we have no doubt a remedy for this will soon be found. There certainly does seem some manner of manufacturing the silk in skeins, because amongst the many fabrics made from the ailanthus silk and sent over by Father Fantoni from China, there were some made with silk in one continuous thread, and which had preserved the gray colour of the ailanthus cocoons. In the meantime, whilst this is being discovered, these cocoons are treated like the mulberry cocoons. They are carded, and then the material is obtained, analogous to what is obtained from the mulberry silkworm. This material, of a brownish-gray colour, carded,