Oocyte development in the ovary of the black cricket, Melanogryllus desertus, was investigated. In the panoistic ovary of M. desertus, oocyte developmental stages based on their histological properties were classified as previtellogenic, vitellogenic, and maturation. Oocytes were encircled by follicle cells through the developmental stages. In the previtellogenic stage, a few vacuoles were observed just beneath the oolemma. At the beginning of the vitellogenic stage, subdivided into early-, middle-, and late-vitellogenic stages, yolk granules within the oocyte were initially observed just beneath the oolemma. In addition, small lipid droplets were initially present under the yolk granules. As vitellogenesis proceeded, both yolk granules and lipid droplets gradually increased and moved inside the oocyte. The Balbiani body was detected around the nucleus. In the maturation stage, large yolk granules covering the whole of the oocytes were determined. Some atretic oocytes occurring as a result of resorption of oocytes (oosorption) by hypertrophied follicle cells were also detected. Apoptosis in atretic follicles was observed as well.