Abstract: The ultrastructure of olfactory sensilla on the antenna of Proagopertha lucidula (Faldermann) adult was studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the olfactory sensilla concentrated on antennal lamellae and all these sensilla were situated in cuticle or in the sunken cavity formed by antennal cuticle depressions. Five types of olfactory sensilla in lamellae were found. There are mainly sensilla placodea (S. pl) in lamellae of P. lucidula. In addition to S. pl, there are sensilla basiconca (S. ba), sensilla cavitica (S. ca), sensilla coeloconica (S. co) and sensilla trichodea (S. tr). Based on the differences of plate and cone shape, S. pl are further classified into four subtypes, S. ba into two subtypes, and S. co into two subtypes. There are a plenty of pores and pore tubules in the cuticle of olfactory sensillum. The number of neurons in olfactory sensilla is inconsistent, including one olfactory receptor neuron (ORN), or two ORNs. The total number of sensilla in the male is 1.8 times that in the female. The number of S. bal in male is two times that in female, the number of S. co in female is four times that in male, while the number of S. pl in male is two times that in female. There is no significant difference in the number of S. co between male and female.

Key words: Proagopertha lucidula, olfactory sensillum, ultrastructure, sexual dimorphism, scanning electron microscopy (SEM), transmission electron microscopy (TEM)