Male accessory reproductive glands (MARG), testis (including its sheath) and abdominal integument along with adhering fat body were cultured invitroto determine their ability to synthesize ecdysteroid during the first 10 days of adult development. Ecdysteroid synthesis by MARG was highest on day 2 (0.180 ng/mg) while the testis showed a peak on day 5 (0.436 ng/mg). In the testis, the sheath is mainly responsible for ecdysteroid synthesis. Ecdysteroid is also synthesized by the abdominal integument with adhering fat body, and peak activity is observed on day 8 (0.50 ng/mg). A time-course study showed that ecdysteroid synthesis increased linearly in all tissues over a 24-h incubation period. However, little storage of ecdysteroid occurred in the tissues.