Silkworm

SILKWORM. The Silkworm has attracted so much attention in all civilized countries where it may be propagated and raised for the silk which is obtained from the cocoons spun by the larvte, and especially in the United States, where much money has from time to time been spent in establishing this industry, that more than a passing notice is deemed necessary. There is no reason why the rearing of silkworms may not be practiced in any portion of the United States south of 40', the only question being the cost of labor in attending them. We believe the only two States where the industry is profitably carried on at present is in California and Kansas. The importance of the silk industry and the increasing demand for these products, as wealth increases, will undoubtedly prevent any glutting of the market, since the price of silk fabrics has steadily increased for the last forty years until now the possession of real silk fabrics, unmixed with other material, for dresses is beyond the reach of any but the more wealthy. So impor tant was this industry considered that Dr. Riley was employed by the government of the United States to write a manual on the habits and rear ing of the worm and the puperation of the cocoons, and the food-plants of the worms, to which the reader is referred for information not contained in this article. From Dr. Riley's manual, we extract as follows: The Silkworm proper, or that which supplies the ordinary silk of commerce, is the larva of a small moth known to scientific men as bericaria MOH. It is often popularly characterized as the Mulberry Silk worm. Its place among insects is with the Lepidoptera, or Scaly-winged insects, family Bombycida, or Spinners. There are several closely allied species, which spin silks of different qualities, none of which, however, unite strength and fineness in the same admirable proportions as does that of the mulberry species. The latter has, moreover, acquired many useful peculiarities during the long centuries of cultivation it has undergone. It has in fact become a true domes ticated. animal. The quality which man has endeavored to select in breeding this insect is, of course, that of silk producing, and hence we find that, when we compare it with its wild relations, the cocoon is vastly disproportionate to the size of the worm which makes it or the moth that issues from it. Other peculiarities have incidentally appeared, and the great number of varieties or races of the Silkworm almost equals those of the domestic dog. The white color of the species; its seeming want of all desire to escape as long as it is kept supplied with leaves, and the loss of the power of flight on the part of the moth, are all undoubtedly the result of domestication. From these facts, and particularly from that of the great variation within specific limits to which the insect is sub ject, it will be evident to all that the following remarks upon the nature of the Silkworm must necessarily be very general in their character. The ,silkworm exists in four states—egg, larva, chrysalis, and adult or imago. The egg of the Silkworm moth is called by silk-raisers the seed. It is nearly round, slightly flattened, and in size resembles a turnip seed. Its color when first deposited is yellow, and this color it retains if unimpregnated. If impregnated, however, it soon acquires a gray, slate, lilac, violet, or even dark green hue, according to variety or breed. It also becomes indented. When diseased it assumes a still darker and dull tint. With some varieties it is fastened to the substance upon which it is deposited, by a gummy secretion of the moth produced in the act of ovipositing. Other varieties, however, among which may be mentioned the Adrianople whites and the yellows from Nouka, in the Caucasus, have not this natural gum. As the hatching point approaches, the egg becomes lighter in color, which is due to the fact that its fluid contents become con centrated, as it were, into the central, forming worm, leaving an intervening space between it and the shell, which is semi-transparent. Just before hatching, the worm within becoming more active, a slight clicking sound is frequently heard, which sound is, however, common to the eggs of many other insects. After the worm has made its exit by gnawing a hole through one side of the shell, this last becomes quite white. Each female produces on an average from three to four hundred eggs, and one ounce of eggs contains about 40,000 individuals. It has been noticed this the color of the albuminous fluid of the egg corresponds to that of the cocoon, so that when the fluid is white the cocoon produced is also white, and when yellow the cocoon again corresponds. The worm goes through from three to four molts or sicknesses, the latter being the normal number. The periods between these different molts are called ages, there being five of these ages including the first from the hatch ing and the last from the fourth molt to the spinning period. The time between each of these molts is usually divided as follows: The first period occupies from five to six days, the second but four or five, the third about five, the fourth from five to six, and the fifth from eight to ten. These periods are not exact, but simply proportionate. The time from the hatching to the spinning of the cocoons may, and does, vary all the way from thirty to forty days, depending upon the race of the worm, the quality of the food, mode of feeding, temperature, etc.; hut the same relative proportion of time between molts -usually holds true. The color of the newly hatched worm is black or dark gray, and it is covered with long stiff hairs, which, upon close examination, will be found to spring from pale colored tubercles. Different shades of dark gray will, however, be found among worms hatching from the same batch of eggs. The hairs and tubercles are not noticeable after the first molt and the worm gradually gets lighter and lighter until,,in the last age, it is of a cream-white color. When full grown it presents the appearance of Fig. 1. It never becomes entirely smooth, how ever, as there are short hairs along the sides, and very minute ones, not noticeable with the unaided eye, all over the body. The preparation for each molt requires from two to three days of fasting and rest, during which time the worm attaches itself firmly by the abdominal prolegs. In front of the first joint a dark triangular spot is at this time noticeable, indicating the growth of the new head: and when the term of sickness is over, the worm casts its old integument, rests a short time to recover strength, and then, fresh ened, supple, and hungry, goes to work feeding voraciously to compensate for lost time. This so-called sickness which preceded the molt was, in its turn, preceded by a most voracious appe tite, which served to stretch the skin. In the operation of molting, the new head is first dis engaged from the old skin, which is then grad ually worked back from Segment to segment until entirely cast off. If the worm is feeble, or has met with any misfortune, the shriveled skin may remain on the end of the body, being held by the anal horn; in which case the indi vidual usually perishes in the course of time. It has been usually estimated that the worm in its growth consumes its own weight of leaves every day it feeds; but this is only an approxi mation. Yet it is certain that during the last few days before commencing to spin. it con sumes more than during the whole of its pre vious worm-existence. It is a curious fact, first noted by Quatrefages, that the color of the abdominal prolegs at this time corresponds with the color of the silk. Having attained full growth, the worm is ready to spin up. It shrinks somewhat in size, voids most of the excrement remaining in the alimentary canal; acquires a clear, translucent, often pinkish or amber-colored hue ; becomes restless, ceases to feed, and throws out silken threads. The silk is elaborated in a fluid condition in two long, slender, convoluted vessels, one upon each side of the alimentary canal. As these vessels approach the head they become less convoluted and more slender, and finally unite within the spinneret, from which the silk issues in a glutin ous state, and apparently in a single thread. The glutinous liquid which combines the two, and which hardens immediately on exposure to the air, may, however, he dissolved in warm water. The worm usually consumes from three to five days in the construction of the cocoon, and then passes in three days more, by a final molt, into the chrysalis state. The cocoon con sists of an outer lining of loose silk known as floss, which is used for carding, and is spun by the worm in first getting its bearings. The amount of this loose silk varies in different breeds. The inner cocoon is tough, strong, and compact, composed of a firm, continuous thread, which is, however, not wound in concentric circles, as might fairly be supposed, but irregularly, in short figure-of-eight loops, first in one place and then in another, so that in reeling, several yards of silk may be taken off without the cocoon turning round. In form the cocoon is usually oval, and in color yellowish, but in both these features it varies greatly, being either pure silvery-white, cream or carneous green, and even roseate, and very often constricted in the middle. It has always been considered possible to distinguish the sex of the contained insect from the general shape of the cocoon, those con taining males being slender, depressed in the middle, and pointed at both ends, while the female cocoons are of a larger size and rounder form, and resemble in shape a hen's egg with equal ends. The chrysalis is a brown, oval body, considerably less in size than the full grown worm. In the external integument may be traced folds corresponding with the abdomi nal rings, the wings folded over the breast, the autennte, and the eyes of the enclosed insect— the future moth. At the posterior end of the chrysalis, pushed closely up to the wall of the cocoon, is the last larval skin, compressed into a dry wad of wrinkled integument. The chrys alis state continues for from two to three weeks, when the skin bursts and the moth emerges. With no jaws, and confined within the narrow space of the cocoon, the moth finds some diffi culty in escaping. For this purpose it is pro vided, in two glands near the obsolete mouth, with a strongly alkaline liquid secretion with which it moistens the end of the cocoon, and dissolves the hard gummy lining. Then: by a forward and backward motion, the prisoner, with crimped and damp wings, gradually. f orces its way out, and when once out the wings soon expand and dry. The silken threads are simply pushed aside, but enough of them get broken in the process to render the cocoons, from which the moths escape, comparatively useless for reeling. The moth is of a cream color, with more or less distinct brownish markings across the wings. The males have broader antenna', or feelers, than the females, and may, by this fea tnre, at once be distinguished. Neither sex flies, but the male is more active than the female. They couple soon after issuing, and in a short time the female begins depositing her eggs, whether they have been impregnated or not. Domestication has had the effect of producing numerous varieties of the Silkworm, every differ ent climate into which it has been carried having produced either some changes in the quality of the silk, or the shape or color of the cocoons; or else altered the habits of the worm. Some vari eties produce but one brood in a year, no matter how the eggs are manipulated; such are known as Annuals. Others, known as Bivoltins, hatch twice in the course of a year; the first time, as with the Annuals, in April or May, and the sec ond, eight or ten days after the eggs are laid by the first brood. The eggs of the second brood only are kept for the next year's crop, as those of the first brood always either hatch or die soon after being laid. The Trevoltins produce three annual generations. There are also Quadrivoltins, and in Bengal, a variety known as Dacey which is said to produce eight generations in the course of a year. Some varieties molt but three times instead of four, especially in warm countries and with Trevoltins. Experiments, taking into consideration the size of the cocoon, quality of silk, time occupied, hardiness, quantity of leaves required. etc., have proved the Annuals to be more profitable than any of the polyvoltins, although Bivoltins are often reared ; and Mr. Alfred Brewster, of San Gabriel, Cal., says that he found a green Japanese variety of these last more hardy than the Chinese Annuals. Varie ties are also known, by the color of the cocoons they produce, as Greens, or Whites, or Yellows, and also by the country in which they flourish. The white silk -is most valuable in commence, but the races producing yellow, cream-colored, or flesh-colored cocoons are generally considered to be the most vigorous. No classification of varieties can be attempted, as individuals of the same breed exported to a dozen different locali ties would, in all probability, soon present a dozen varieties. The three most marked and noted European varieties are the Milanese (Italian), breed, producing fine, small, yellow cocoons; the Arache (French), producing large yellow cocoons, and the Brousse (Turkish), producing large white cocoons of the best quality in Europe. Owing to the fearful preva lence of pebrine among the French and Italian races for fifteen or twenty years back, the Japanese Annuals have come into favor. The eggs are bought at Yokohama in September, and shipped during the winter. There are two prin cipal varieties iu use, the one producing white and the other greenish cocoons, and known respectively as the White Japanese and the Green Japanese Annuals. These cocoons are by no means large, but the pods are solid and firm, and yield an abundance of silk. They are about of a size, and both varieties are almost always constricted in the middle. Another valuable race is the White Chinese Annual which much resembles the White Japanese but is not as gen erally constricted. We have already seen the importance of getting healthy eggs, free from hereditary disease, and of good and valuable races. There is little danger of premature hatch ing until December, but from that time on, the eggs should be kept in a cool, dry room -in tin boxes to prevent the ravages of rats and mice. They are most safely stored in a dry cellar, where the temperature rarely sinks below the freezing point, and they should he occasionally looked at to make sure that they are not affected by mold. If at any time, mold be perceived upon them it should be at once rubbed or brushed off, and the atmosphere made drier. If the tin boxes be perforated on two sides and the perfo rations covered with fine wire gauze, the chances of injury will be reduced to a minimum. The eggs may also, whether on cards or loose, be tied up in small bags and hung to the ceiling of the cold room. The string of the bag should be passed through a bottle neck or a piece of tin to prevent injury from rats and mice. The temper ature should never he allowed to rise above 40° Fahr., but may be allowed to sink below freez ing point without injury. Indeed, eggs sent from one country to another are usually packed in ice. They should be kept at a low tempera ture until the mulberry leaves are well started in the spring, and great care must be taken as the weather grows warmer to prevent hatching before their food is ready for them, since both the Mulberry and Osage Orange are rather late in leafing out. One great object should be, in fact, to have them all kept back, as the tendency in our climate is to premature hatching. Another object should be to have them hatch uniformly, and this is best attained by keeping together those laid at one and the same time, and by win tering them as already recommended, in cellars that are cool enough to prevent any embryonic development. They should then, as soon as the leaves of the food plant have commenced to put forth, be placed in trays and brought into a well-aired room where the temperature aver ages about 75° Fahr. If they have been wintered adhering to the cloth on which they were laid, all that is necessary is to spread the same cloth over the bottom of a tray. if, on the contrary, they have been wintered in the loose condition, they must be uniformly sifted or spread over sheets of cloth or paper. The temperature should be kept uniform, and a small stove in the hatching-room will prove very valuable in pro viding this uniformity. The heat of the room may be increased about two degrees each day, and if the eggs have been well kept back during the winter, they will begin to hatch under such treatment on the fifth or sixth day. By nO means must the eggs be exposed to the sun's rays, which would kill them in a very short time. As the time of hatching approaches, the eggs grow lighter in color, and then the atmosphere must be kept moist artificially by sprinkling the floor, or, otherwise, in order to enable the worms to eat through the egg-shell more easily. They also appear fresher and more vigorous with due amount of moisture. The room in which the rearing is to be done should be so arranged that it can be thoroughly and easily ventilated, and warmed if desirable. A northeast exposure is the best, and buildings erected for the express purpose should, of course, combine these requi sites. If but few worms are to be reared, all the operations can be performed in trays upon tables, but in large establishments the room is arranged with deep and numerous shelves from four to eight feet deep and two feet and six inches apart. All wood, however, should be well seasoned, as green wood seems to be injuri ous to the health of the worms. When the eggs are about to hatch, mosquito-net ting or perforated paper should be laid over them lightly, Upon this can be evenly spread freshly plucked leaves or buds. The worms rise through the meshes of the net or the holes in the paper and cluster upon the leaves, when the whole net can cosily be moved. In this ' preparation for moving, paper has the advantage over the netting; it is stiffer and does not lump the worms together in the middle. They may now be spread upon the shelves or trays, care being takeu to give them plenty of space, as they grow rapidly. Each day's/hatching should be kept separate in order that the worms may be of a uniform size, and go through their different moltings or sick nesses with regularity and uniformity; and all eggs not hatched after the fourth day from the appearance of the first should he thrown away, as they will be found to contain inferior, weakly, or sickly worms. • It is calculated that one ounce of eggs of a good race will produce 100 pounds of fresh cocoons; while for every additional ounce the perceptage is reduced if the worms are all raised together, for twenty ounces the average does not exceed twenty-five pounds of cocoons per ounce. Such is the general ence throughout France, according to Gu6rin Meneville, and it shows the importance of ing them in small broods, or of rearing on a moderate scale. The young worms may be removed from place to place by means of a small camel's-hair brush, but should be handled as little as possible. The best mode of feeding and caring for them is by continuing the use of the net first mentioned As the worms increase in size the uet must have larger meshes, and if it should be used every time fresh food is furnished, it will save a large amount of time and care. It entirely obviates the necessity • of handling the worms, and en ables the person having charge of them to keep them thoroughly clean ; for, while they pass up through the net to take their fresh food, their excrement drops through it and is always taken, up with the old litter beneath. It also acts as a detective of dis ease; for such worms as are in jured, feeble, or sickly, usually fail to mount through the meshes and should be carried off and destroyed with the refuse in the old net below. Placing on of the new net and carrying away of the old is such a great venience and time-saver that, in France, for many years, paper, stamped by machinery with holes of different sizes, suited to the different stages of the worms, has been used. The paper has the advantage of cheapness and stiffness, but a discussion as to the best material is sary here, the aim being to enforce the principle of the progressive rise of the worms. Details will suggest themselves to the operator. Where the nets are not used, there is an advantage in feeding the worms upon leaf-covered twigs and branches, because these last allow a free passage of air, and the leaves keep fresh a longer time than when plucked. In thus feeding with branches consists the whole secret of the Califor nia system, so much praised and advocated by M. L. Prevost. The proper, stamped paper not being easily obtained in this country, mosquito netting will be found a very fair substitute while the worms are young, and when they are larger I have found thin slats of some non-resinous and well-seasoned wood, tacked in parallel lines to a frame just large enough to set in the trays, very serviceable and convenient—small square blocks of similar wood being used at the corners of the tray to support the frame while the worms are passing up through it, Coarse twine-netting stretched over a similar frame will answer the same purpose, but wire-netting is less useful, as the worms dislike the smooth metal. Where

branches, and not leaves, are fed, the Osage Orange has the advantage of Mulberry, as its spines prevent too close settling or packing, and thus' insure ventilation. It is recommended by many to feed the worms while in their first age, and, consequently, weak and tender, leaves that have been cut up or hashed, in order to give them more edges to eat upon and maltdless work for them. This, however, is hardly necessary with Annuals, although it is quite generally practiced in France. With the second brood of Bivoltins it might be advisable, inasmuch as the leaves at the season of the year when they appear, have attained their full growth and are a little tough for the newly-hatched individuals. In the spring, however, the leaves are small and tender, and nature has provided the young worms with sufficiently strong jaws to cut them. Many rules have been laid down as to regularity of feeding, and much stress has been put upon it by some writers, most advising four meals a day at regular intervals, while a given number of meals between molts has also been urged; but such definite rules are of but little avail, as so much depends upon circumstances and condi tions. The food should, in fact, be renewed whenever the leaves have been devoured, or whenever they have become in the least dry, which, of eourse, takes place much quicker when young and tender than when mature. This also is an objection to the use of the hashed leaves, as, of eourse, they would dry very quickly. The worms eat most freely early in the morning and late at night, and it would be well to renew the leaves abundantly between 5 and 6 a. m. and between 10 and 11 p. m. One or two additional meals should be given during the day, according as the worms may seem to need them Great eare should be taken to pick the leaves for the early morning meal the evening before, as when picked and fed with the dew upon them they are more apt to induce disease. Indeed, the rule should be laid down, never feed wet or damp leaves to your worms. In ease they are picked during a rain, they should be thoroughly dried before being fed ; and on the approach of a storm, it is always well to lay in a stock, which should be kept from heating by occasional stir ring. Care should also be taken to spread the leaves evenly, so that all may feed alike. Dur ing this first and most delicate age the worm requires much care and watching. As the fifth or sixth day approaches, signs of the first molt begin to be noticed. The worm begins to lose appetite and grow more shiny, and soon the dark spot already described appears above the bead. Feeding should now cease, and the shelves or trays should be made as clean as possible. Some will undoubtedly undergo the shedding of the skin much more easily and quickly than others, but no feed should be given to these forward individuals until nearly all have completed the molt. This serves to keep the batch together, and the first ones will wait one or even two days without injury from want of food. It is, how ever, unnecessary to wait for all, as there will always be some few which remain sick after the great, have east their skins. These should either be set aside and kept separate, or destroyed, as they are usually the most feeble and most inclined to disease; otherwise, the batch will grow more and more irregular in their molt ings and the diseased worms will assuredly contaminate the healthy ones. It is really doubt ful whether the silk raised from these weak viduals will pay for the trouble of rearing them separately, and it will be better perhaps to des troy them. The importance of keeping each batch together, and of causing the worms to molt simultaneously, can not be too much insisted upon as a means of saving time. As soon as the great majority have molted they should be copi ously fed, and, as they grow very rapidly after each molt, and as they must always he allowed plenty of room, it will probably become neces sary to divide the batch, and this is readily done at any meal by removing the net when about half of the worms have risen and replacing it by' an additional one. The space allotted to each batch should, of course, be increased proportion ately with the growth of the worms. The same precautions should be observed in the three suc ceeding molts as in this first one. As regards the temperature of the rearing-room, great care should be taken to avoid all sudden changes from warm to eold, or vice versa. A mean temperature of 75° or 80° F. will usually bring the worms to the spinning-point in the course of thirty-five days after hatching, but the rapidity of development depends upon a variety of other causes, such as quality of leaf, race of worm, etc. If it can be prevented, the temperature should not be per mitted to rise very much above 80°, and it is for this reason that a room with a northern or north eastern exposure was recommended as preferable to any other. The air should be kept pure all of the time, and arrangements should be made to secure a good circulation. Great care should be taken to guard against the incursions of ants and other predaceous insects, which would make sad havoc among the worms were they allowed an entrance, and all through the existence of the insect, from the egg to the moth, rats and mice are on the watch for a chance to get at them, and are to be feared almost as much as any other enemy the Silkworm has. The second and third casting of the skin takes place with but little more difficulty than the first, hut the fourth is more laborious, and the worms not only take more time in undergoing it, but more often perish in the act. At this molt it is perhaps better to give the more forward individuals a light feed as soon as they have completed the change, inasmuch as it is the last molt and but little is to be gained by the retardation, whereas it is important to feed them all that they will eat, since much of the nutri ment given during the last age goes for the elab oration of the silk. At each sueeessive molt the color of the worm has been gradually whitening, until it is'now of a decided cream color. Some breeds, however, remain dark, and occasionally there is an individual with zebra-like markings. During these last few days the worms require the greatest eare and attention. All excrement and litter must be often removed, and the sickly and diseased ones watched for and removed from the rest. The quantity of leaves which they devour in this fifth age is something enormous, and the feeding will keep the attendant busily employed. Summed up, the requisites to successful Silk worm raising are: 1. Uniformity of age in the individuals of the same tray, so as to insure their molting simultaneously. 2. No intermission in the supply of fresh food, except during the molt ing periods. 3. Plenty of room, so that the worms may not too closely crowd each other. 4. Fresh air and as uniform temperature as pos sible. 5. Cleanliness. The last three are par ticularly necessary during fourth and fifth ages. While small, the frass, dung, and detritus dry rapidly, and may, though they should not, be left for several days in a tray with impunity, but he who allows his trays to go uncleaned for more than a day during the ages mentioned will suffer in the disease and mortality of his worms just as they are reaching the spinning-point. With eight or ten days of busy feeding, after the last molt, the worms, as we have, learned before, will begin to lose appetite, shrink in size, become restless, and throw out silk,and the arches for the spinning of, the cocoons must now be prepared. These can be made of twigs of different trees, two or three feet long, set up upon the shelves over the worms, and made to interlock in the form of an arch above them. Interlace these twigs with broom-corn, hemlock, or other well dried brush. The feet of each arch should be only about a foot apart. The temperature of the room should now be kept about 80°, as the silk does not flow so freely in a cool atmosphere. The worms will immediately mount into the branches and commence to spin their cocoons. They will not, all, however, mount at the same time, and those which are more tardy should be fed often, but in small quantities at a time, in order to economize the leaves, as almost every moment some few will quit and mount. There will always be a few which altogether fail to mount, and to spin in their trays. It is best, therefore, after the bulk have mounted, to remove the trays and lay brush carefully over them. The fact that the worms already mounted make a final discharge of soft and semi fluid excrement before beginning to spin makes this separation necessary, as otherwise the cocoons of the lower ones would be badly soiled. As the worms begin to spin they should be care fully watched, to guard against two or three of them making what is called a double or treble cocoon, which would be unfit for reeling pur poses. Whenever one worm is about to spin up too near another, it should be carefully removed to another part of the arch. In two or tbree days the spinning will have been completed, and in six or seven the chrysalis will be formed. Eight days from the time the spinning commenced, it will be time' to gather the cocoons. The arches should be carefully taken apart, and the spotted or stained cocoons first removed and laid aside. Care should be taken not to stain the clean ones with the black fluids of such worms as may have died and become putrid, for there are always a few of these in every cocoonery. The outer cocoons of loose or floss silk are then torn from the inner cocoons or pods, and the latter separ ated according to color, weight, and firmness of texture; those which best resist pressure indicat ing that the worm has best accomplished its work. Too much care can not be taken to remove the soft or imperfect cocoons, as, if mixed with the firm ones, they would be surely crushed and soil the others with their contents. The very best of the firm cocoons are now to be chosen as seed for the next year, unless the raiser prefers buying his eggs to the trouble of caring for the moths and keeping the eggs through the winter. Eggs bought from large establishments are, however apt to be untrustworthy, and it is, well for all silk-raisers to provide their own seed. These cocoons should be chosen for their firmness, and the fineness and color of the silk, rather than for their size. Mr. Crozier says: If white, take them of the purest white, neither soft nor satin-like; if yellow, give preference to the straw-colored, which are the most sought after; and, last, if they are the green of Japan, the greener they are, of a dark, sharp color, very glossy, the better is the quality of the thread. Discard the pale shades in the last breed. If there are any double or treble cocoons in the batch, of the right color, quality, and con sistency, they should be used before the others, as they are just as good for breeding purposes, though unfit for reeling. In estimating the quantity that will be required, the following figures will be of use: The general estimate is always made of 40,000 eggs to the ounce, and also that each female lays from 300 to 400 eggs. Taking the higher estimate, it will require only 100 females to lay an ounce of eggs; taking the lower, it will require 133. It will, therefore, not be safe to take fewer than 200 cocoons, half males and half females, if an ounce of seed is desired, and from that to 225 would be safer. While it may not always be possible to deter mine the sex of the cocoons by their shape, we may approximately separate them by weighing. The whole quantity set aside for breeding pur poses is first weighed in order to get the aver age, and then each one is weighed separately, and all above the average may be pretty accu rately considered females and all below it males, These breeding cocoons should now be either pasted upon card-board on their sides, or strung upon a string, great care being taken to run the needle through the silk only and not deep enough to injure the chrysalis, the object being in both cases to secure the cocoon so that the moth can the more readily make its escape. They can be laid aside in a rat-proof place to await the appear ance of the moths, and in the mean time the other cocoons should be taken care of. In most silk producing countries the parties who raise the cocoons sell them to the reeling establishments before suffocation is necessary, as these estab lishments have better facilities for this work than are to be found in private families. If, how ever, the reeling is done by the raiser, or some time must elapse before the cocoons can be sent to a reeling establishment, some means must be used to kill the contained chrysalis before the cocoon is injured for reeling purposes by the egress of the moth. This can be done by stifling them with steam or choking them by dry heat. Steaming is the surest, quickest, and best method, if the facilities are at hand. It can be done at any steam mill. The cocoons are laid upon shelves in a tightly-sealed box and the steam is turned in. Twenty minutes will suffice to do the required work, and the cocoons are then dried in the sun. The dry heat method occupies a much longer time The cocoons are placed in shallow baskets and slipped on iron drawers into an oven which is kept heated to a tempera ture of about 200° Fahr. This should not be increased for fear of burning the silk. This ope ration lasts from two to twenty-four hours. A certain humming noise continues so long as there is any life, and its cessation is an indica tion that the chrysalids are all dead. Where the choking is well done there is little loss, only about one per cent, of the cocoons bursting at the ends. After choking in this manner, the cocoons should be strewn upon long, wooden shelves in the shade, with plenty of air, and, for the first few days, frequently stirred. After remaining on these shelves for about two months, with occasional stirrings, the chrysalids become quite dry and the cocoons will pre serve indefinitely. They are, however, still sub ject to the attacks of rats and mice, and the lit tle beetles knowu as museum pests, belonging to the genera D-3rmestes and Anthrenus, are attracted by the dead chrysalis within and will penetrate the cocoon, injuring it for reeling pur poses. In the warm, Southern States the dry heat choking can be accomplished by simple exposure to the sun. This was done by M. L. Prevost, in Southern California, and is practiced habitually by Mr. Crozier in Silkville, Kansas, who says: Here the cocoons need only to be fully exposed to the rays of the sun, from nine o'clock in the morning till four o'clock in the afternoon. Two or three days of such exposure are sufficient. But, as some time strong wind can annihilate the effect of the sun's warmth, it is good to have for that purpose long boxes, four feet wide, sides six inches high, to be cov ered with glass frames. This will increase the heat, and, by absorbing the air of the box, stifle your chrysalis most surely. Ed. Muller, another California grower, (Nevada county), always makes use of this method of stifling by the sun's rays, but says that the glass cover of the box should be left cracked open to allow the evapo ration of the moisture, which otherwise would collect in large drops upon the glass, and, falling back upon the cocoons, would keep them moist for a longer time. Do not, however, allow the ants to creep in at the crack, as they too will penetrate the cocoon to feed upon the chrysalis. In the colder climates it has been suggested that the chrysalis could be well choked, with no injury to the cocoons, by placing them in a vacuum box and exhausting the air. Chloro form has been used to a certain extent, and experiments are now being made in France with sulph-hydric acid gas, a vapor which is evolved from the mixture of dilute sulphuric acid and sulphide of iron ; also with bisulphide of carbon. In from to twelve to twenty days from the time when the worm commenced to spin,the moths will begin to issue from the cocoons laid aside for breeding purposes. They issue abundantly dur ing the early morning hours, from four to eight o'clock, and as they appear, they should be taken by the wings and the sexes kept apart for a short time. The males may be readily distin guished from the females by their broader antenna; and smaller bodies, as also by the inces sant fluttering of their wings. The females remain comparatively quiet, their abdomens being heavy and distended with eggs. A few hours after issuing, the sexes, in equal numbers, may be placed together, great care being taken to destroy any that are at all deformed, in order to keep the breed as fine as possible. They should be placed upon paper or card-board, and the room should be kept as dark as possible in order that the males shall not uncouple them selves. For the complete impregnation of the eggs, the sexes should be kept together six hours, neither more nor less, and occasionally visited in order to replace those males which may have become separated. Should there, on this day. more males than females issue, the super fluous males may be put in a closed box and kept till the next day, when the state of things may be reversed. Should there, on the other hand, he a superfluity of females, a sufficient number of the strongest and most vigorous males should be uncoupled at four hours and placed with the unpaired females for six hours more. As the pairs are uncoupled at the end of six hours, care should be taken to injure neither sex. The female should be held by the wings with one hand and the abdomen of the male gently pressed with the other. The males may then be laid aside in a box, as there may be use for them before all the moths have appeared. After all the females are impregnated, however, they may be thrown away. These last, as soon as separated, should be placed for a few minutes upon sheets of blotting-paper, where they will free themselves of a quantity of greenish-yellow fluid. From the blotting-paper they should be transferred to trays lined with cloth upon which the eggs are to be laid. This cloth should be of the smoothest sort of woolen stuff rather than of linen or paper, if it is desired to remove the eggs at a future time, as they will stick so fast to the latter that it will be difficult to remove without bruising them. Upon these trays they may be placed in rows, and will immediately commence depositing. It is advisable to tip up the trays at one end so that they incline a little, as the moths are then more apt to lay their eggs uniformly. They should also be kept in the dark, in accord ance with the nocturnal habit of the moth. The temperature of the room should be kept at about 75°, and plenty of air given during oviposition. All of the thoroughly impregnated eggs will be laid in about twenty-four hours, and the moth should be removed after that length of time. She may continue depositing a short time longer, but the eggs should be kept by themselves and not mixed with the others. It will be well, also, if the best and purest breed be desired, to keep the eggs of those moths which were coupled with males that had been used before, separated from the eggs laid by those which were coupled with virgin males. The eggs are best preserved on the cloth where originally deposited, as they are protected by a natural coating of varnish, and, being fastened, the worms, when hatching, eat their way out better. For commercial purposes, however, they are usually detached during the winter by immersing the cloth containing them in cool, soft water for a few moments; the moist ure being then drained off by means of blotting paper, and the eggs gently removed with a paper-knife. They are then washed in soft water, thoroughly dried, and put away for keep ing. All eggs which swim on the surface are considered bad and discarded. The Japanese producers sell their eggs on cards or cartoons made of coarse silk. The cards are placed in wooden frames, the rims of which are varnished, so that the moths—disliking the varnish—are made to confine their eggs upon the cards, which are consequently covered in a very regular and uniform manner. The egg retains the character istic color of the unimpregnated ones—light yellow—for twelve or fifteen days, when it gradually acquires the gray, lavender, or ish tint of impregnation. The moths live but a few days after having perpetuated their kind.