Deliberations on the External Morphology and Modification of the Labial Segments in the Nepomorpha (Heteroptera: Insecta) with Notes on the Phylogenetic Characteristics

Figure 26

Shapes of the labial segments of the Naucoridae. Naucorinae, (a)-(b) Macrocoris rhantoides, (c)–(e) Neomacrocoris handlirschi. (a) Dorsal view (D) of the labium, the first segment (I) invisible, the second segment with the triangular plate partly visible, the stylet groove in the II, III and IV segments is closed, (b) ventral view (V), the first segment with the midventral condyle (cv) and the proximal edge of the fourth segment, the apical plate is present, (c) the shape of the segments, dorsal view (D), the second segment is divided into the triangular plate (tr) and the convex plate (cp), the articulation between the second and third segments (cd), (d) the intercalary sclerites (is) are slightly visible, and (e) ventral view (V), the proximal edge of the fourth segment possess the midventral condyle (cv), the apical plate can be observed. Lr: labrum, stb: stylet bundle.