COMPARISON BETWEEN ENDOGENOUS AND EXOGENOUS YOLK PROTEINS ALONG AN OVARIAN CYCLE IN THE FIREBRAT THERMOBIA-DOMESTICA (INSECTA, THYSANURA)

1. In the primitive insect, Thermobia domestica, the two sex-specific proteins of the female are generated by both the fat body and the ovaries. 2. Production from both origins was studied along an ovarian cycle and in relation to the moulting cycle. Data designate the ovaries as the highly preponderant source of yolk proteins, but only the fat body metabolism appears clearly stimulated after insemination. 3. In the ovaries, the early yolk protein synthesis and its high specific activity from the onset of a reproductive cycle indicate early translation and gene amplification necessary to support the massive endogenous production.