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

Figure 25

Types and sizes of the sensilla of the Pleidae (Paraplea frontalis). (a) CH2 and CH3 are less numerous and spread unevenly over all segment; TRS1 (one) is placed dorsally near the apex; one pair of COS is situated on the II segment. (b) TRS1 (three) are located ventrally near the apex; one pair of CH3 is situated near the proximal edge of the IV segment; one pair of CH3 is situated ventrally on the III segment; several CH3 are visible on the ventral side of the II segment, and some COS are located near the edge of the I segment; no sensila can be seen on segment I (ventral view). (c) TRS1 (one), TRS2 (one), and CH3 (two) are situated on the dorsal surface of the IV segment. (d) CH2 (several) are situated on the dorsal side and CH3 (several) are situated on the lateral side of the III segment. (e) Several CH3 are present on the III segment dorsally as well as one pair of COS. (f) PAS2 (no. 2–9) are placed in a circle on the labial tip, and PIP (no. 1) is situated centrally.