Abstract: Mouthpart sensilla play significant roles in insect feeding activities. However, sensilla on the mouthparts in adult hangingflies have not been reported. The mouthpart sensilla of Bittacus sinensis Walker adults were investigated using scanning electron microscopy. The results indicated that the sensilla are mainly borne on the epipharynx and maxillary and labial palpi, and can be categorized into eight types: basiconic, trichoid, chaetic, digitiform, palmate, campaniform, cylindrate sensilla and Böhm’s bristles. Basiconic and chaetic sensilla are the most abundant. Trichoid sensilla are mainly located on the cardines, stipites, submentum and mentum. Campaniform sensilla and Böhm’s bristles are only distributed on the maxillary and labial palpi. The sensilla are similar on the distal segments of maxillary and labial palpi, mostly being basiconic sensilla. No sensillum was discovered on the highly sclerotized mandibles, galeae and laciniae. The implication of the mouthpart sensilla in insect classification is briefly discussed.  

Key words: Mecoptera, Bittacidae, mouthparts, sensillum, morphology, scanning electron microscopy (SEM)