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

Figure 21

Shapes of the labial segments of the Naucoridae. Cheirochelinae, (a) Coptocatus oblongulus, (b)-(c) Coptocatus kinabalu, (d)–(f) Tanycricos longiceps. (a)-(b) Dorsal and lateral views (D-L) of the labium, the shape of the first segment (I) and intersegmental sclerites (si), the dorsal surface of the second segment (II) is divided into the triangular plate (tp) and the convex plate (cp), in the second segment (II) the stylet groove is closed, the articulation of the dorsal condyle (cd) between the II and III, segments, the shape of the intercalary sclerites (is) with the visible membrane (ms), the conical shape of the IV segment, (c) the dorsal surface of the second segment (II) is divided into the triangular plate (tp) and the convex plate (cp), the lateral membrane with the intersegmental sclerit (si) viewed in detail, (d) the shape of the segment on the dorsal side (D), dorsal view of the first segment with the open stylet groove (gr), the second segment is divided into the triangular plate (tp) and the convex plate (cp), the articulation of the dorsal condyle is distinctly visible, the stylet groove is closed in the II, III and IV segments, the intercalary sclerites are present, the conical shape of the fourth segment, (e) the intercalary sclerites magnified, the membranes of these sclerites are marked, and (f) ventral view on the segments, the connection between the third and fourth segments, the midventral condyle (cv) and the apical plate (ap) can be observed. Lr: labrum, stb: stylet bundle.