Proteases, glycosidases, and lectins were tested and the results supported a role in host recognition for glycoproteins containing[beta]-glucose and[alpha]-mannose on the cuticular surface of host and parasite. Carbohydrates containing[alpha]-glucose, galactose, fucose, or N-acetylglucosamine residues apparently are not involved in nematode attachment. Chitin or a related N-acetylglucosamine polymer was found in R. culicivorax preparasites. Treatment of preparasites with neuraminidase, which hydrolyzes sialic acids, increased nematode attachment to Anophelesfreeborni larvae. Key words: Anophelesfreeborni, carbohydrate, host recognition, mosquito cuticle, nematode cuticle, Romanomermis culicivorax.