Böhm bristles
Böhm’s bristle sensor (Bb) is present at the base of the labial palpus and mandibular palpus only at the junction of the base of the first segment with the mouthparts, and the sensor has a smooth epidermal wall with an acute tip and a loose basal fossa (Fig. 5). This sensor is a relatively common sensor at the junction of insect organs, and no subtypes exist, which it shows no significant differences between males and females as a whole (Fig. 3).