Essential Compendium of Sericulture

The "sleep" the dormant period when a silkworm molts its skin of silkworms values uniformity; it is best when they enter sleep together and wake up together. If the feeding of mulberry leaves is uneven, those that have eaten their fill will sleep early, while those who have not had enough will sleep late. Within a single basket, those beginning their sleep sleep-heads (眠頭); silkworms just starting the molting process and those still eating become a chaotic and crowded mix. If you continue to feed them, the active "neighbors" will grow larger and risk damaging the dormant sleep-heads. If you stop feeding them, the active ones will lack food and become even less able to enter their sleep. In such cases, you must quickly remove the active eaters from the surface to feed them elsewhere, while placing the sleep-heads from the bottom into a separate container; this method is called "Separating the Old Bottoms." Although the silkworms gathered from the surface cannot be compared to "green silkworms" original: "qing can" (青蠶); healthy, fully active silkworms, their final harvest will never be as abundant as that of the "Old Bottoms" the silkworms that molted on schedule at the bottom of the tray.

The Molting and Awakening of Second-Stage Silkworms

The nature of second-stage silkworms is vastly different from that of the first stage. In the first stage, the times for molting and waking are clearly divided into morning and evening. For the second stage, if they do not enter sleep during the evening hours, any that show signs of sleep during the day will generally be able to sleep uniformly by dusk. However, if signs of sleep appear during the Shen hour the period from 3:00 PM to 5:00 PM, but by late evening only half have entered their sleep, the remainder will not sleep until noon the following day. These two groups must be separated and stored in different containers. If every molting period were as irregular as this, the work of separating them would be endless. Hence the local proverb: "Second-stage silkworms involve eighteen divisions" a metaphor for the many different groups or "batches" one must manage due to uneven growth. The nature of the third and fourth stages is much the same.