Abstract: Caryedon crineus Arora (Coleoptera: Bruchidae) infesting seeds and pods of Cassiaoccidentalis and Cassia tora have been investigated for biology and biological control. Bothlegumes are major weeds of Arachis hypogaea and Glycine max in southern USA and some partsof the tropics, but are of significant importance in some Asian subcontinents where they areedible and yield valuable medicines. Work has also been extended to study the bio control ofC. crineus by a koinobiont parasitoid, Eurytoma raoi Narendran (Hymenoptera: Eurytomidae).The potential biocontrol agent is short-lived, fast developing and complete its development at thecost of host insects. Biocontrolling potential of some eurytomid parasitoids has been done, but nowork has been carried out so far on E. raoi to explore its efficacy on bruchid pests. Therefore, thepresent work on biology of C. crineus on two different hosts, C. occidentalis and C. tora and itsbiological control by a hymenopteran parasitoid has been worked out.