The polytene chromosomes found in the salivary gland cells are among the largest chromosomes known today.
唾液腺细胞中的多线染色体是目前已知的最大染色体之一。
The midgut gland cell differentiation occurs at Z2, There are 4 types of cells, i. e., embryonic cell (E-cell), fibrillar cell (F-cell), blister cell (B-cell) and resorptive cell(R-cell).