Silkworms breed by eggs, which look like grains of sesame and are 1 mm wide, 0.5 mm thick. A female moth can produce about 450-500 grains of silkworm eggs, weighing about 1 g. When they are just laid, they are light yellow or yellow eggs. They turn into red-bean color after 1-2 days and then become sage green or purple through 3-4 days later. From then on, their color no longer changes, known as the fixed color. Silkworm eggs have outer hard shells, with egg yolk and serous in it. Zygote embryo continuously absorbs nutrition in the process of growth, gradually developing into newly-hatched silkworms, and then climb out from the egg shell. The egg shells are white or light yellow when empty.
Newly-hatched silkworms-matured silkworms
Newly-hatched silkworms: When just hatched from eggs, their body is brown or russet, tiny, and fuzz, looking like ants, so they are also called ant silkworms. Ant silkworms are about 2 mm long, 0.5 mm wide. After they leave the shells, they begin to eat mulberry leaves 2-3 hours later.
Newly hatched silkworms-matured silkworms: Silkworm babies eat a lot, therefore, they grow fast with body color gradually becoming weak. But sometimes their appetite gradually wanes and even fast. Vomiting out a small amount of silk, fixing gastropod on rearing bed, raising cephalothorax, resting as if asleep, this period is known as "Dormant Period". Silkworms in this period seem motionless, but their bodies are preparing for peeling. It’s also called “Aging”, showing the silkworms are in a certain development stage. The first aging is when ant silkworms peel for the first time; They are in the second aging period when they are awake; It’s the third aging period when they peel again; When they peel for the third time, whey enter into the fourth period, the fourth molting is also called “Long sleep”; Just after the long sleep, it’s the fifth aging period. Silkworms grow very fast in this period, their body can be up to 6-7 cm long, weighing about 10000 times heavier than the newly-hatched silkworms.
Matured silkworms: Silkworms gradually reflect the aging characteristics when they are in the fifth period: Firstly, their shit turn from soft to shit and from dark green to green; Then they lose the appetite and eat less; Their anterior digestive tube is empty and turn transparent; Afterwards, they completely stop eating with a shorter body and transparent abdomen. Silkworm raise their cephalothorax, spinning silk, bobbing around looking for cocoon camp sites. Such silkworms are called matured silkworms.
Cocoon when matured
人們把熟蠶放在特制的容器中或蔟器上，蠶便吐絲結繭了。 結繭可分為四個過程：1、熟蠶先將絲吐出，粘結在蔟器上，再吐絲連接周圍蔟枝，形成結繭支架，即結繭網。繭網不具備繭形，只是一些松軟凌亂的繭絲層，以作為結繭的支架。2、蠶結制繭網后，繼續吐出凌亂的絲圈，加厚繭網內層，然后以S型方式吐絲，開始出現繭的輪廓，叫做結繭衣。繭衣的絲纖維細而脆，排列極不規則，絲膠含量也多。 3、繭衣形成后，繭腔逐漸變小，蠶體前后兩端向背方彎曲，成“C”字型，蠶繼續吐出繭絲，吐絲方式由S形改變成∞形，這就開始了結繭層的過程。4、當蠶由于大量吐絲，體軀大大縮小時，頭胸部擺動速度減慢，而且沒有一定的節奏，吐絲開始顯得凌亂，形成松散柔軟的繭絲層，稱為蛹襯。
After people put matured silkworms in a special container or straw cocooning frame, silkworms begin to spin cocoons. Cocoons can be divided into four processes: 1. Spiting out silk first, binding on the straw cocooning frame machine, then spinning again to connect the branches around straw cocooning frame, forming the bracket of cocoon, that is making cocoon nets. Cocoon nets does not have cocoon shape, they are just some soft and messy cocoon layer as the framework of the cocoon. 2. After silkworm finish making cocoon nets, they continue to spit out messy silk circles, thicken the endotheciums of cocoon nets and then spin silk out in S way. Finally, the outline of cocoon appear, called cocoon garments.
The silk fiber of cocoon garments is thin, brittle, highly irregular and contain much sericin. 3. Cocoon cavity, after the formation of cocoon, gradually become smaller. Silkworms bend both their hands and tails to the direction of their back into a "C" word and then continue to spit silk from S way to ∞, which starts the process of cocoon layer. 4. Their bodies are greatly smaller because the silkworms spin a large quantity of silk. Their cephalothorax’s swing speed slow down without certain rhythm. The spinning is starting to be messy, forming a loose and soft cocoon layer, which is called tetelettes.
silkworm chrysalises-Silkworm moths
Silkworm chrysalis: 4 days after silkworms make cocoons on straw cocooning frame, they will turn into silkworm chrysalises. The shape of silkworm chrysalises are like spindles with three individual segments: head, chest and abdomen. Their heads are small with compound eye and tentacles; they have thoracic legs and wings on their chest and nine sections on their abdomens. Professionals can tell their gender from observing the abdominal lines and brown dots. When silkworms just become chrysalis, their body is light yellow, tender and soft. Gradually they become yellow, yellowish-brown or brown and their skin is harder. After about 12 to 15 days, their bodies become soft, the skin is a little wrinkle and tan. They will become moths at this time.
Silkworm moth (matured): The shape of the silkworm moth are like butterflies wearing white scales, but they can’t fly because their two pairs of wings are too small. Silkworm moths’ heads are round and little with summoned compound eyes and tentacles; There are three pairs of thoracic legs and two pairs of wings on their chest and no thoracic leg on their abdomen; The end somites evolve into genitals. The female moths’ bodies are big and creep slowly while the male moths’ body are small, climbing faster and keep looking for their mates. Generally after they mating after 3-4 hours, the female moths can lay eggs. The male moths will die just after the mating while the female moths will die slowly after they lay about 500 eggs for an evening.
After the Tussahs breeding period, professionals will harvest cocoons in time, then select the best cocoons to be raw materials. Tussah silk has unique jewelry burnish, natural and elegant, smooth and comfortable, soft and elastic, which is the best choice to be silk carpet material. On the basis of the original purchasing selection, the factory inspector will still need to filter the new cocoons, to ensure the silk which will be made into carpets is with absolutely quality assurance. During the selection, the cocoons’ size, color, elasticity, smell, etc are all inspectors’ considerations. For raw materials, YISI has its own set of standard system.Through rounds of quality control, only the highest quality cocoons can eventually be used to make handmade silk carpets.
Using the most traditional manual silk reeling method, put the cocoon into clean water to remove impurities and then again use clean water to filter for 1-3 times. After the filtration, put them into boiling water for 20 minutes, then begin to reel off silk from cocoons. Raw cocoon of one kilogram can be reeled off 0.3kg silk, the thickness depends on the materials needed.
The silk processing is very complex, open the strands of silk at first, put it on more than five manual spelling silk machines to merge, the thickness depends on the lines needed, several strands become one strand at last. And then they are prepared to dye.