(6/9)
At the night of June 7, about a half of larvae falled in fouth
sleep(upper picture). Bigger head capsule of fifth instar is seen
under head capsule of fourth instar(arrow).
About a half of larva became fifth instar on the morning of June
9. Newly ecdysed fifth instar larva is about 4cm(lower picture).
Fifth instar is last larval period. Fifth instar larva is feeding
much leaves, growing bigger and bigger till spinning cocoon.
(6/12)
On June 12, the third day of fifth instar, bombyx larvae become
about 7-8cm, are eating mulberry leaves for all day and night.
Twenty larvae placed on 35 x 25cm tray (picture), eat mulberry
leaves in 6 to 8 hours. A larva eats one leaf as large as adult
palm par a day.
The larvae will be deadly eating for 2 or 3 days, and gradually
stop eating. After that, they will be spinning cocoons.
(6/17)
On June 17, the 8th day of fifth instar, many bombyx larvae
stop feeding, and climb the rim of basket to search suitable place
to spinning cocoon. They eagerly spin much threads. Such conditions
are called "agari" (it means 'up' in japanese). These
larvea looks rather transparant color (because they stop feeding),
shortend (6-7cm). They incline to move brighter, higher place.
Sometimes they escape basket, spin cocoons unexpected place.
In sericulturists, frameworks called "mabushi" (made
of either thick paper, plastics or straws) are used for the place
to spinning cocoon. I use cake boxes (this time of year, I become
fat...sigh) for that purpose. 7 to 10 larvea are put in a box
(picture below). A cocoon spinning for about one day (arrow) is
fully shaped but soft and thin. A larva inside cocoon works eagerly
to make cocoon hard and thick.