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

Figure 14

Shapes of the labial segments of the Belostomatidae (Lethocerinae). (a)–(d) Lethocerus deyrollei. (a) The shape of the first (I) and the second (II) segments, the stylet groove (gr) is opened, the shape of the proximal part of the second stylet groove is opened, the articulation of the dorsal condyle (cd) between the II and III segments on the dorsal side, (b) dorsal view (D) of the labium, the III and IV segments are visible, the articulation of the dorsal condyle (cd) between the II and III segments on the dorsal side, intercalary sclerites (is) on the III segment, (c) lateral view on the second segment. (d) Ventral view (V), the second segment is short, the third segment is the longest, the connection between the third and fourth segments on the ventral side, the midventral condyle (cv) on the third segment is clearly visible, and the shape of the apical plate. Lr: labrum, Pp: posterior plate of the cranium.