The main theme of my mission is to provide feeders and to supply interesting exotic silkworms to educators. But if you are looking to have spinnable silk, it is advised that you use leaves instead of chow. Keep the silkworms at 78 degrees and have food at ALL TIMES. Anything less than that you would prolong the larval life. Typically, larval stage is only about 28-30 days depending on lines, but if you starve them, keep them cold, they will NOT have produce good silk quality for you. Typically, the silkworms available here are meant as feeders and are commercially developed as hybrids with lines of different voltinity, which often is a bivoltine strain meant for hardiness. In general, these silkworms produce coarse silk, sometimes too thick that the moth has a hard time emerging, which means you will have to cut it out, or that the silk is thin and the cocoon is very small...  As I blogged earlier, my father is in China and is helping to obtain some silk quality eggs from a well known sericulture institute. Hope it all works out with that.