The protein pattern in the haemolymph of male and female Rhynchophorus ferrugineus has been characterized. Native polyacrylamide gel electrophoresis (PAGE) analysis revealed eleven protein bands in adult males, ten in adult females and nine in the young female. Male haemolymph showed an additional protein band when compared with that of adult female haemolymph, whereas, in adult as well as young female a female specific protein band was present. The protein metabolism of an insect could be studied by observing the haemolymph protein pattern.