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

Figure 26

Types and sizes of the sensilla of the Helotrephidae (Hydrotrephes visayasinensis). (a) Several CH3, one CH2, and one CH1 are spread dorsally (D) oil the IV segment. (b) TRS1 (one) and TRS2 (one) are situated dorsally (D) near the apex. (c) Several CH3 and four CH1 are situated ventrally on the IV segment; several CH2 are situated on the III segment. (d) CH2 are placed near the labial groove and also near the distal edge of the III segment. (e) TRS1 (two) and TRS2 (two) are situated in two tufts, ventrally, near the apex of the labium. (f) Sensory field (SFR) with PAS2 (no. 1, 3–13) and PIP sensilla (no. 2). (g) COS are present on the dorsal surface of the IV segment, and several CH1 are present on the first segment.