Morphology: cells of various types with the spherical cells predominating; Karyology: cultured cells are polyploid with a chromosome number ranging from 20 to 180; Growth characteristics: doubling time = 27 hr; Authentication: isozyme profiles of this cell line are different from other silkworm cell lines: viz., Bm-N and Bm-0; Unique properties: ultrastructure changes when treated with Bacillus thuringiensis delta-endotoxin.