Extirpation of pars intercerebralis neurosecretory cells (PINSC) of femaleD. cingulatus significantly brought down the level of protein synthesis in the fatbodies 48, 72, and 96 hr after the operation, while implantation of active PINSC into both normal and PINSCablated females elevated substantially the protein content in the fatbodies. Additional supply of JHa (FME) by topical application activated protein synthesis in the fatbodies both in the allatectomised and normal females. Histochemical studies to demonstrate the protein content in the fatbodies of the above experimental insects also corroborated these findings. Probable regulatory mechanism of protein synthesis in the fatbodies of femaleD. cingulatus by the hormonal principles from PINSC and corpus allatum are discussed in the light of the above findings.