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).

中肠腺小管上皮在Z2期细胞已有了分化，由4类细胞组成，即胚细胞(E细胞)、纤维细胞(F细胞)、泡状细胞(B细胞)和吸收细胞(R细胞)。