“…The three morphological types of olfactory sensilla are further classified into several subtypes on the basis of the ultrastructural features of the cuticular apparatus ( Schaller, 1978 ). Comprehensive electrophysiological recordings from single olfactory sensilla have revealed that OSNs in different sensillar types differ in their selectivity and sensitivity to ligands ( Altner et al., 1977 ; Boeckh and Ernst, 1987 ; Fujimura et al., 1991 ; Sass, 1978 , 1983 ; Tateishi et al., 2020 ), suggesting that OSNs in different types of olfactory sensilla express different repertories of olfactory receptors. In addition, in the cockroach, two parallel olfactory pathways stem from OSNs in perforated basiconic and trichoid/grooved basiconic sensilla, which feed information to partly overlapping but distinct types of Kenyon cells in the mushroom body via distinct types of projection neurons ( Watanabe et al., 2010a , 2012 , 2017 ; Takahashi et al., 2019 ).…”