. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. IS THE IMAGO [CH, two lateral pieces or lobes. The broad base is considered to be formed by the fusion of the sub-mentuni {sm) and mentum (m). Fused with the mentum distally is the projecting median lobe (ml), probably representing the ligula of other mandibulate insects. The form of this lobe varies greatly. In the Zygoptera and the older Anisoptera it is very prominent and definitely bifid (fig. 6 a). In the Aeschninae (fig. 5) the median cleft has disappeared, but. Fig. 6. A. Labium of Synlestes weyersi Selys ( x 25). b
. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. IS THE IMAGO [CH, two lateral pieces or lobes. The broad base is considered to be formed by the fusion of the sub-mentuni {sm) and mentum (m). Fused with the mentum distally is the projecting median lobe (ml), probably representing the ligula of other mandibulate insects. The form of this lobe varies greatly. In the Zygoptera and the older Anisoptera it is very prominent and definitely bifid (fig. 6 a). In the Aeschninae (fig. 5) the median cleft has disappeared, but. Fig. 6. A. Labium of Synlestes weyersi Selys ( x 25). b. Labium of Diplncodes haematodes Burm. ( x 15). cl cleft of median lobe; other refeiences as in fig. 5. Original. a slight median groove or line marks the place of its disappearance. In addition, one or two hard black tubercles may project on either side of this median groove. In the Lihellulidae (fig. 6 b) the median lobe is reduced to a small triangular piece, over which the huge lateral lobes fold so as to meet one another in a long median line. On either side of the mentum, the base is widened by the development of two side-pieces or squames (sq) which support the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Tillyard, Robin John, 1881-1937. Cambridge [Eng. ] : University Press
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