Comparative Analysis and Systematic Mapping of the Labial Sensilla in the Nepomorpha (Heteroptera: Insecta)

Figure 5

Types and arrangements of the labial apical sensilla of the Nepomorpha. (a) PAS1 papilla-like sensillum, flattened. (b) PAS2 papilla-like sensillum, rounded. (c) PIP peg-in-pit sensillum, only the pit is visible. (d) Peg-in-pit sensillum, the peg is visible. (e) PAS1 sensilla are circularly placed on the smooth, rounded labial tip with a slightly lateral position of the PIP. These are arranged symmetrically on the right (SFR) and left (SFL) sensory field. (f) PAS2 sensilla are circularly placed on the folded labial tip. The PIP are invisible. They are arranged symmetrically on the right (SFR) and left (SFL) sensory fields. (g) PAS2 sensilla are circularly placed on the labial tip with the central position of the PIP sensillum; the left (SFL) sensory field is shown. (h) PAS2 sensilla are irregularly placed on the labial tip. These sensilla are arranged symmetrically on the right (SFR) and left (SFL) sensory fields. PES form a short row; RBS ribbon-like sensilla (mechanosensilla) are not numerous.