Differentiation of the oocyte and nurse cells in an apterygote insect (Campodea).

Differentiated complexes of cystocytes in an apterygote insect (Diplura: Campodea sp.) are arranged in unbranched chains. Cystocyte lying approximately in the centre of a chain differentiate into the oocyte: two cells adjoining the oocyte and connected with it via cytoplasmic bridges develop into the 'intermediate cells'. Other cystocytes become typical 'nurse cells'. The intermediate cells are structurally transitional between oocytes and nurse cells. In this account, factors controlling the differentiation of oocytes and nurse cells are discussed.