Normal oogenesis in the adult wasp, Habrobracon juglandis, is described. Accounts are given of: (1) the mitotic behavior of oogonia and cystocytes: (2) the production of synaptonemal complexes by pro-oocytes in the germarium; (3) the formation of an egg chamber and its movement through the vitellarium; (4) the ultrastructural details of the transfer of cytoplasmic organelles to the oocyte by the nurse cells; and (5) the production of accessory muclei and protein yolk spheres in the ooplasm. Comparisons are drawn between Habrobracon and other insects with respect to: (1) the cystocyte divisions, the origin of ring canals, and the control of pro-oocyte differentiation; (2) the possible symbiotic relationships of bacteria which reside in ovarian tissue; (3) the proposed functions performed by accessory nuclei and protein yolk spheres; and (4) the synthesis of rRNA by the nurse cells.

The canals connecting the ovarian cystocytes of Habrobracon juglandis are enclosed by a ring made up of eight leaves. Each leaf is composed of a monolayer of between and 70 short parallel microtubules which may be derived from the mid-body. The sliding of certain leaves past one another allows the ring to dilate as the cystocyte grows.