CULTURE OF SILKWORMS. The leaf of the white mulberry (Mores alba) is apparently the nat ural food of the domestic silkworm. There are many horticultural varieties of this plant, some much better adapted than others to commercial silk culture, and some better suited to certain localities. The .Mores moretti, the Mores multi mills, and the black mulberry (]Torus nigra) are also used. The red mulberry (]Torus rubra) does not make good food, and the paper mulberry (Broussonetia papyrifera) is also valueless. The best varieties of mulberries are propagated by means of seeds and by cuttings. The trees should be planted well apart and should be pruned so as to form a short trunk and a close low head. Silkworm eggs are kept through the winter at a low temperature, the embryo beginning to take form when the temperature rises above 50° F. The re ceptacle in which they arc stored should be - ventilated, the air should not be moist, and great care should be taken to keep them out of the reach of mice and insects. The eggs are hatched in an artificial incubator or by natural heat. When an incubator is used the tempera ture should be gradually increased until 73° F. is reached. The whitening of the eggs de notes the near approach of the hatching. The eggs should then be covered with sheets of tulle or finely perforated paper, sprinkled over with finely cut white mulberry leaves. The young caterpillars will at once mount to the leaves, and should be fed eight to ten times during twenty-four hours. After each feeding the lower sheet of perforated paper or tulle should be re moved with the frays. About the sixth day they will begin to molt and pass into the second stage. As the worms increase in size. paper in which the perforations are larger should be used, and the same general directions followed for each stage until the fifth has been reached.
The worms have now grown to nearly full size, and are very voracious, and it is very difficult to satisfy their appetite. After five days in the fifth stage they are ready to spin. In making preparations for spinning, dry brush, bundles of straw or shavings or finely split-up wood may be used. The brush or straw should be placed up
right between the feeding shelves. in rows, about 16 inches apart. the tops spread out to form arches and to allow the worms plenty of room to spin. The temperature during spinning should be 75° F., and the humidity through out the rearing about The rearing-room should he well ventilated, and before introduc ing the worms should he disinfected with chloride of lime or sulphur. One ounce of eggs con tains approximately 40.000, and the space re quired may be estimated by allowing one square yard for this amount at birth, on the fourth day two square yards. for the second stage four square yards. three days later eight square yards. for the third stage 16 square yards. for the fourth stage 32 square yards, and for the fifth stage 60 square yards. Plenty of space is desirable, since when crowded the worms will not be so robust. A mean temperature of about 74° F. is the best. There are many commer cial varieties of the silkworm graded ac cording to the size, color, and quality of the co coon. When the cocoons are completed, which is known by the absence of any sound within, they are carefully sorted, and a certain number are kept for laying. The sexes are readily known by the difference of shape as well as of size, the female being plumper and the male, besides being much smaller, having a central de pression and sharper extremities. The French growers sort them into nine varieties, those which are less compact, or in which the worm has dicd—a fact known by external indications —being separated from the good ones. When the sorting is finished. the cocoons are placed in an oven with a gentle heat, which kills the inclosed chrysalis. otherwise they would all be come perforated by the insect eating through. The cocoons are then ready for the first stage in the manufacturing process. which consists in the removal and winding of the fibrous cover ing as described under SILK.