||The female silkworm, Bombyx mori, rapidly accumulates two storage proteins in the haemolymph that are synthesized by the fat body during the final stage of the last larval instar. This is then sequestered from the haemolymph in to the fat body during larval -pupal transformation. Application of Methoprene (Manta) at low concentration ranging from 0.1 mg -1 mg on the third day was found to prolong the larval period by two days in a dose dependent manner which resulted in the prolonged synthesis of storage proteins as evidenced by the SDS -PAGE and densitometric scanning of haemolymph proteins. A corresponding decline in the storage protein concentration was observed in the fat body samples in lieu of the late sequestration. The prolonged synthesis of storage protein in the study was found to have an indirect impact on the silk as observed in enhanced silk production.