. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. Fig. 12. Diagram to shew the position of the anal appendages of the male, viewed fi-om behind, a in Anisoptera, b in Zygoptera a anus; «;/inferior appendage; la lamina supra-analis; /a'laminae sub-anales; sij^^'bipartite eleventh sternite; sup superior appendages; t^ eleventh tergite. Original. while the superior appendages become engaged between the pro- thorax and the back of the head, and most usually press forward against the latter. Thus the head is held as it were between the jaws of a vice (fig. 13 a). In the Petalu
. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. Fig. 12. Diagram to shew the position of the anal appendages of the male, viewed fi-om behind, a in Anisoptera, b in Zygoptera a anus; «;/inferior appendage; la lamina supra-analis; /a'laminae sub-anales; sij^^'bipartite eleventh sternite; sup superior appendages; t^ eleventh tergite. Original. while the superior appendages become engaged between the pro- thorax and the back of the head, and most usually press forward against the latter. Thus the head is held as it were between the jaws of a vice (fig. 13 a). In the Petalunnae, however, the broad leaf-like superior appendages (fig. 13 b) fit closely upon the mesepi- sterna, while the wide inferior appendage, placed upon the occiput, presses the head back so as to hold the superiors in position. In a number of forms with long or forcipate superior appendages, a similar kind of grip seems to be the rule, though undoubtedly the chief pressure is on the head. In the Goni'phinae the inferior appendage is strongly bifid, en- gaging the broad occiput in two depressions; while the superiors, which are too short to be of much direct use, are generally held in place by tubercles or other out- growths from the back of the occiput. In the Petaliini (fig. 14) the inferior appendage is trifid and very long; the superiors very short. The method of pairing has not yet been observed. T. I).-F. 3. 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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