. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. 30 THE IMAGO [CH. ventral pieces of the tergite are so turned in as to overlap and partly hide the sternite from view, especially in the dead insect. Owing to its great extent and convexity, the tergite is strength- ened by the formation of both longitudinal and transverse ridges of hard chitin, called carinae. The following carinae may be present: (i) Mid-dorsal carina {dc, longitudinal). This occurs very generally, particularly in the larger Fig. 10. Urosternite and right half of urotergite from Petalura gigaiite
. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. 30 THE IMAGO [CH. ventral pieces of the tergite are so turned in as to overlap and partly hide the sternite from view, especially in the dead insect. Owing to its great extent and convexity, the tergite is strength- ened by the formation of both longitudinal and transverse ridges of hard chitin, called carinae. The following carinae may be present: (i) Mid-dorsal carina {dc, longitudinal). This occurs very generally, particularly in the larger Fig. 10. Urosternite and right half of urotergite from Petalura gigaiitea Leach { X 5h). ac anterior carina; dc dorsal carina; pc posterior carina; plm pleural membrane; pr posterior prolongation of sternellum; sap sternal apodemes; sp abdominal spiracles; st sternum; stl sternellum ; tc supplementary trans- verse carina; tg, tg' urotergite; vc ventral carina. Original. (ii) Ventral carinae {vc, longitudinal, paired). These border the pleura, and are nearly always present. (iii) Supplementary lateral carinae (longitudinal). They occur along the angle separating the ventral from the lateral portion of the tergite. They are only found in Aeschninae and Libellulidae. (iv) Anterior and posterior transverse carinae {ac, pc). These are nearly always present. They serve to separate successive segments from one another, leaving between them a narrow belt. 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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Keywords: ., bookcentury1900, bookdecade1910, bookpublishercambridgeenguniver
