Abstract: 【Aim】 This study aims to clarify the types and distribution of antennal sensilla of flower-visiting insect Bibio rufiventris. 【Methods】 The type, quantity and morphology of antennal sensilla of B. rufiventris were observed with scanning electron microscope (SEM), and their differences between male and female adults were compared. 【Results】 The female and male adult antennae of B. rufiventris include three parts, scape (Sc), pedicel (P) and flagellum (F), and the flagellum consists of eight flagellomeres. The average lengths of antennae of female and male adults are 862.556±78.662 and 880.361±83.253 μm, respectively. There is significant difference in the length of the 8th flagellomere, while the lengths of other flagellomeres are almost equal. Four types of sensilla including sensilla chaetica (Sc), sensilla basiconca (Sb), sensilla trichodea (St) and Böhm bristles (Bb) were observed on the female and male antennae. The antennal sensilla of female adults have six subtypes, i.e., sensilla chaetica (Sc), sensilla trichodea subtype 2 (St.2), sensilla basiconca subtypes 1, 2 and 4 (Sb.1, Sb.2 and Sb.4) and Böhm bristles (Bb), while those of male adults have five subtypes, i.e., sensilla chaetica (Sc), sensilla trichodea subtype 1 (St.1), sensilla basiconca subtype 2  (Sb.2) and sensilla basiconca subtype 3 (Sb.3) and Böhm bristles (Bb). 【Conclusion】 The types, amounts and characteristics of antennal sensilla of B. rufiventris adults show some 
differences between females and males. This study provides a morphological basis for studying the physiological functions of these sensilla and the molecular mechanisms of behavioral activities of B. rufiventris. 

Key words: Bibio rufiventris, flower-visiting insect, antennal sensilla, morphological characteristics, quantity distribution, scanning electron microscopy