A poly(U), poly(C) specific RNase of apparent MW 34 kDa has recently been purified from 6 day old larvae of the insect Ceratitis capitata. Two monoclonal antibodies were obtained by immunizing mice with this protein. Immunoblot analysis of the RNase revealed that both antibodies recognize the 34 kDa protein. Furthermore, immunoprecipitation experiments show that both antibodies were capable of precipitating the ribonuclease without affecting its catalytic activity.