The presence of glycoconjugates in apyrene and eupyrene spermatozoa of the noctuid moth Anticarsia gemmatalis was examined using ruthenium red and direct lectin-gold labeling techniques. Acid mucopolysaccharides of the plasma membrane of apyrene spermatozoa and the lacinate appendages of eupyrene spermatozoa were stained by ruthenium red. The lacinated appendages of eupyrene spermatozoa were the most intensely labeled structures when lectins were used as histochemical probes. Sugar residues were also present in the dense cap of apyrene spermatozoa and in the nucleus of eupyrene spermatozoa. There was no labeling in the acrosome of eupyrene spermatozoa. These results indicate that the two categories of spermatozoa have different types and distributions of glycoconjugates which probably reflect their distinct functions during differentiation and fertilization.