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).

中腺小管上皮在Z2期细已有了化，由4类细组成，即胚细(E细)、细(F细)、泡状细(B细)和吸收细(R细)。