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

Figure 33

Shapes of the labial segments of the Notonectidae. Notonectinae. (a)–(e) Nychia sappho. (a) Dorsal view of the shape of the segments (I, II, III, and IV), the first segment is wide, the stylet groove is covered by the labrum, (b) dorsal view of the labium, the first segment with the open t stylet groove (gr), the second segment, at the base of this segment the stylet groove is opened, the third segment is tubular, he fourth segment is conical, the stylet groove (gr) in III and IV segments is closed, (c) dorsal view (V) of the segments in detail, the second segment is divided dorsally into the triangular plate (tp) and the convex plate (cp), the articulation between the II and III segments is visible, (d) the shapes and sizes of the reduced intercalary sclerites, and (e) lateral view, the first segment has a midventral condyle (cv) on the distal edge, this segment is narrower ventrally than dorsally, the second segment is narrower dorsally than ventrally, the III segment is tubular, the IV segment is conical, on the fourth segment there is the midventral condyle (cv) but it is only slightly visible, the trapezoidal apical plate (ap) can be observed. Lr: labrum.