SEM images of the 2nd valvula of Habrobracon hebetor a overview of the 2nd valvula (ventral aspect with the interlocked 1st valvulae removed) b proximal part of 2nd valvula featuring the bulbs c apex of 2nd valvula with the ending of the rhachises (arrow) and campaniform sensillae (medioventral aspect) d–e middle part of the 2nd valvula showing the rhachises and distally oriented ctenidia f sensilla at the apex of the 2nd valvula (detail image of c). Abbreviations: 2vv = 2nd valvula; blb = bulb; cs = campaniform sensilla; ct = ctenidia; rh = rhachis.