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

Figure 13

Shapes of the labial segments of the Belostomatidae. (a)–(d) Limnogeton fieberi. (a) Dorso-ventral view (D-V) of the labium, all segments and intercalary sclerites are visible (is) (b) the shape of the first segment (I) the dorsal side is clearly visible in a slightly rectangular form and the stylet groove is opened, (c) the shape of the first (I) segment and the proximal part of the second (II) segment, the midventral condyle on the distal edge of the first segment and the intersegmental membrane (mb) are visible, (d) the articulation of the dorsal condyle (cd) between the II and III segments on the dorsal side, the elongated second segment, the second segment has the same width proximally and distally, it is slightly longer than the third. Bu: buccula of posterior plate, gl: orifice of the maxillary gland, Lr: labrum, Mxp: maxillary plate, Pp: posterior plate of the cranium.