Silk
Silk moths lay eggs on specially prepared paper. The eggs hatch and the caterpillars (silkworms) are fed fresh mulberry leaves. After about 35 days and 4 moltings, the caterpillars are 10,000 times heavier than when hatched and are ready to begin spinning a cocoon. A straw frame is placed over the tray of caterpillars, and each caterpillar begins spinning a cocoon by moving its head in a pattern. Two glands produce liquid silk and force it through openings in the head called spinnerets. Liquid silk is coated in sericin, a water-soluble protective gum, and solidifies on contact with the air. Within 2–3 days, the caterpillar spins about 1 mile of filament and is completely encased in a cocoon. The silk farmers then heat the cocoons to kill them, leaving some to metamorphose into moths to breed the next generation of caterpillars. Harvested cocoons are then soaked in boiling water to soften the sericin holding the silk fibers together in a cocoon shape. The fibers are then unwound to produce a continuous thread. Since a single thread is too fine and fragile for commercial use, anywhere from three to ten strands are spun together to form a single thread of silk.
Stigmella hoheriae
The females lay eggs on the surface of a still growing leaf of their host plant. Larva have been recorded from February to August and are 2–3 mm long and pale transparent green. They mine the leaves of their host plant. The mine consists of blotches, mainly on the lower leaves. The mine is narrow and crosses over itself several times, but rarely passes larger leaf ribs. The frass is deposited in a straight, granular line medially in the mine. The cocoon is spun from dark brown silk (from larvae found on "Hoheria lyalli" and "H. glabrata") οr pale whitish silk (larvae on other "Hoheria" species). It is located amongst the debris at the base of the food plant. Adults are mainly on the wing from August to November. However adult moths have been recorded in February and from July to December indicating there are likely two generations per year.