Changes in the free amino acid levels of tissue extracts from 3rd instar boll weevil Anthonomus grandis Boheman larvae which had been stung once by the ectoparasitoid Bracon ellitor say (Braconidae) females were determined. Stung larvae exhibited an initial rise in free amino acid levels within 6 min. after the venom was injected followed by a decline within hr. A second free amino acid peak occurred 4 days after initial sting. Observed increases in free amino acid levels, were always followed by synchronized decreases in total soluble proteins. The possible nutritional regulatory effect of ectoparasitoid venom on the physiology of boll weevil was discussed.