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Silk Worms (Strung tron threads and hung)
strung tron threads, and hung against a wall, or suspended from a beam. Just so much of the middle of the cocoon is to be pierced with a needle as is sufficient to attach it to the thread. The middle is chosen, because it cannot be ascertained at which end the moth will pierce the cocoon.
Place a male and female cocoon alternately upon the thread, that they may be near each other when they come out.
If the heat of the apartment is above 73°, every method of diminishing the heat should be tried : such as keeping all the apertures to the sunny side carefully closed, to cause thorough drafts of air to dry the humidity that exhales from the chrysalides. Should the temperature rise to 78° or 82°, the cocoons must be put in a cooler place, as a dry cellar.
Seventh Age of the Silk Worm.
The seventh, and the last age of the silk worm, comprises the entire life of the moth.
The formation of the moth, and its disposition to issue from the cocoon, may be ascertained when one of its extremities is perceived to be wet, which is the part occupied by the head of the moth. A few hours after, and sometimes in one hour after, the moth will pierce the cocoon and come out; occasionally the cocoon is so hard, and so wound in silk, that the moth in vain strives to comes forth, and dies in the cocoon. Sometimes the female deposits some eggs in the cocoon before she can get out, and often perishes in it; this circumstance has induced some to extract the chrysalis from the cocoon by cutting it, that the moth may have only to pierce its thin envelope; but the experienced Dandolo disapproves of the practice (although he has performed the operation with success) because it is tedious; and should the moth be put on a plain surface, five in a hundred will not be able to get out, but will drag the envelope along, and at last die, not being able to disencumber themselves. If the surface be not smooth, the moths will issue with greater ease; it is very favorable to the moths when they put forth their head and first legs, to find some substance to which they may fasten, and thus facilitate clearing out of the cocoon by the support. For this reason they should be spread out very thin on tables covered with a muslin or linen cloth. The life of the moth lasts, in Italy, ten, eleven, or twelve days, according to the strength of its constitution, and the mildness of the atmosphere. With Mr. Dusar, of Philadelphia, the moths lived from five to eight days; a hot temperature accelerates their operations and the drying which precedes their death. Hatching of the Moths, and their Preservation.
Cocoons kept in a temperature of 66° begin to be hatched after fifteen days; those kept in a heat between 71° and 73°, begin to come forth after eleven or twelve days. The room in which the moths are produced should be dark, or at least there should be only sufficient light to distinguish objects. This is an important rule, and must be carefully attended to. The moths do not come forth in great numbers the first or the second day, but are chiefly hatched on the fourth, fifth, sixth, and seventh days, according to the degree of heat in which the cocoons have been kept. The hours when the moths burst the cocoons in the greatest numbers, are the three and four hours after sunrise, if the temperature is from 64° to 66°. The male moths, the very moment they come out, go eagerly in quest of the female; when they are united, they must be placed on frames covered with linen, and made in such a manner as to allow the linen to be changed when soiled.
Much care must be taken in raising the united moths; they must be held by the wings in order not to separate them. When one small table is filled with moths in a state of union, they are to be carried into a small room, sufficiently airy and fresh, and which can be made very dark. Having employed the first hours of the day in selecting and carrying the united moths, the males and females which are found separate on the tables are to be brought into contact, put on frames and carried into the dark room. It is easy to ascertain if there are more females than males. The body of the female is nearly double the size of that of the male; besides, the male which is single, beats about its wings at the least approach of light; the hour must be noted at which the tables containing the united moths are placed in the dark room.
If, after this operation is over, there still remain some moths of each sex, they are to be placed in a small box with a perforated cover, until the moment favorable for their union arrives. From time to time they must be looked at, to see if they separate, in order that they may be brought anew into contact.
When any thing is to be done in the dark chamber, as little light as possible must be admitted, only sufficient to distinguish objects. The more light there is the more the moths are disturbed and troubled in their operations, as light is too stimulating for them. The boxes are very convenient to keep quiet the males which remain, and thus prevent the fine powder adhering to their wings from flying about, and the destruction of their wings, and consequently their vital power.
The cocoons must be removed as fast as they are pierced by the moth, for being moist they communicate their humidity to those which are still entire. The paper also on the trays, when soiled, is to be removed, and fresh supplied. Constant attention is required during the whole day, as there is a succession in the process of hatching, and union of the moths, which occasionally vary in relative proportion to one another. Instead of a frame paper may be used for receiving the eggs.
A few good cocoons will not produce moths, owing to their hardness, which prevents the moth from making a hole by which to come forth.
Separation of the Moth and laying the Eggs.
If there be an excess of males they must be thrown away; if of females, males must be allotted to them, which have already been in a state of union. Great care must be taken when the couples are separated not to injure the males. The male ought not to remain united more than six hours; after the lapse of that time take the moths by the wings and body and separate them gently. All the males which are no longer in union must be placed upon a frame, the most vigorous afterwards selected and united with those females which have not yet had a mate. Other vigorous males must be preserved in a separate box, and kept in darkness. When there is a want of males let them remain united to the female the first time only five hours instead of six; the fe males are not injured by waiting for the male even many hours; the only loss sustained is that of some eggs, which are not impregnated. Before separating the two sexes prepare in a cool, dry, airy chamber the linen on which the moth is to deposit its eggs.
Six hours, as just said, is the usual time for the moths to remain united, for in that time the eggs of the female will be fully impregnated. It is also the general practice not to use the male another female, but Mr. Delonchamps assures us | tity be large, place them on a frame of cord atthat in the event of having more female than male moths, the latter may be again used to profit. In the year 1824 he raised many worms from eggs the produce of a sixth coupling, which were fully equal to those produced from those at the first; the union continued never less than from twenty to twenty-four hours; the male after a sixth union appeared as lively and as brisk as at first, but he had no more females. The eggs from even a thirteenth union of the same male with different females had all the characters of those of the best quality. In these cases the disunion of the pair was, moreover, never spontaneous, but always required to be effected by the hands. The following is the manner in which the cloth must be arranged:
At the bottom of a tressel or frame, which must be proportioned to the number of moths, place horizontally on each side of the length two boards, so arranged that one of their sides may be nailed to the tressel about five inches and a half high above the ground, and that the other side of the board shall be a little higher and project outwards. Upon the tressel lay a cloth, so that it may hang equally on each side. The ends of the cloth must cover the boards below; the more perpendicular the lateral parts of the tressel are the less soiled will be the cloth by the evacuation of the liquid from the moths. The moths which have been united six hours are then to be gently separated, the females placed on the frame and carried to the tressel and placed on the cloth, one over another, beginning at the top and going downwards. Note the time at which the moths are placed on the cloth, and keep those which are placed afterwards separate, to avoid confusion.
The females that have had a virgin mate must be treated ir. the same manner as those which have been united with one that had been coupled previously five hours. The females should be left on the cloth thirty-six or forty hours without being touched; at this time if it be observed that the linen has not been well stocked with eggs, other females must be placed upon it, in order that the eggs may be equally distributed. When the heat of the room is 77° or 79°, or when at 63° or 65°, the eggs will be yellow, that is unimpregnated, or of a reddish color, that is imperfectly impregnated, and will not produce worms; the temperature of the room must therefore be kept between these extremes. Sometimes a female moth will escape from its mate before impregnation and produce many worthless eggs.
The female cocoons, as before noted, are generally larger than the males and not so much pointed as these are, and are without the ring or depression in the middle, which commonly distinguishes the cocoons containing the latter. Eight or ten days after the deposition of the eggs the jonquil color peculiar to them will change to a reddish gray, and afterwards into a pale clay hue; they are of a lenticular form, and on both surfaces there is a slight depression.
Preservation of the Eggs.
Collect the eggs which have fallen on the cloth covering the shelves of the tressel, when quite dry, and put them in a box, and, if numerous, in layers not more than half the breadth of the finger. The cloths raised from the tressel when quite dry are to be folded and placed in a dry room, the temperature of which does not exceed 65°, nor below the freezing point, 32°.
During the summer the cloths must be examined every month, to remove insects, and to pretached to the ceiling or a rafter. A barrel-hoop crossed with stout pack-thread will make a good frame. A small quantity may be kept in a tin case.
If a board box be used the joints and edges of the top should be pasted with paper to exclude ants.
There exists a notion that every two or three years the eggs should be changed. It requires little to be said on this egregious error. To suppose that the good cocoons of a cultivator, after a few years, are no longer fit to produce seed, and yet that these cocoons can give good seed for the use of another, would be to admit a superstitious contradiction, which reason, practice, and science alike condemn. A change of seed can only be necessary when, from great neglect for a series of years of the worms, a diminutive race has been produced. Worms properly treated will never degenerate. On the subject of the degeneracy of silk-worms, in the United States, the most positive information can be given. Mr. Samuel Alexander, of Philadelphia, says: "I am convinced that silk worms cultivated in Pennsylvania, instead of degenerating, improve; proof of which I possess, in comparing the cocoons of four years since with those of the last year. I can say, with truth, the worms hatched from the eggs I brought from the south of Europe have produced annually better silk." The testimony of Mr. Sharrod M'Call, of Florida, is still more decisive.
A sample of beautiful sewing-silk, sent with his communication to the Secretary of the Treasury, was part of a parcel produced by worms, the stock of which he has had thirty years; and they were obtained from a maternal ancestor, who had possessed them many years before. During all this long period no degeneracy has been observed. Let proper care be taken of silkworms, and no deterioration will take place. The time has passed when the idle reveries of Buffon, Robertson, De Pauw, and others, respecting the tendency of nature "to belittle" and degenerate everything foreign in the new world, were received as truths. Facts, proud facts, demonstrate not only the absurdity of their positions, but the superiority of many American animals and vegetables, when compared with similar productions in the old world. To bake Cocoons.
Cocoons reel more readily, and yield silk of a superior quality, without killing the insect by either steam of hot water, or by baking them; but those who have not the means of reeling off their cocoons in two or three days after they are formed, or of selling them, must kill the insects they contain, or they will eat through, and spoil the cocoons by breaking the continuity of the thread. The easiest way to do this is to bake them in an oven, which must be about as hot as when bread has been taken out of it. After picking out all the spotted cocoons, put the rest in flat baskets, filling them within an inch of the top; cover them with paper, and a wrapper over it; put these baskets in the oven, and after an hour draw them out and cover them with a woollen rug, leaving the wrapper as it was. Let them stand five or six hours, to keep in the heat and stifle the chrysalis. Then spread them in thin layers on shelves, and move them every day (to prevent their becoming mouldy) until perfectly dry. It may be important to state that the birth of the moth may be prolonged a month, by keeping the cocoons in a very cold dry cellar. If the cocoons are kept over summer, they must be protected from anta serve the cloths always in fresh air; if the quan- | mice, and cockroaches.