. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. Fig. 67. Labrum (Ibr) and epipharynx {ep)oiAeschna brevistylaF\,amh. (x 20). Underside, shewing brushes of hairs (br), taste-organs (t) and sensillae. Original, chitin preparation. Fig. 68. Section through one of the taste-organs on the labrum of the larva of Aeschna (xlOOO). c cone; en canal; cu cuticle; d disc of hard chitin; /iiinerve-ending. Methylenblue preparation, after Zawarsin. disc of strong chitin of yellow colour (d), and connected with a canal {en) carrying a fine nerve-ending {nc). Some of these organs are al
. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. Fig. 67. Labrum (Ibr) and epipharynx {ep)oiAeschna brevistylaF\,amh. (x 20). Underside, shewing brushes of hairs (br), taste-organs (t) and sensillae. Original, chitin preparation. Fig. 68. Section through one of the taste-organs on the labrum of the larva of Aeschna (xlOOO). c cone; en canal; cu cuticle; d disc of hard chitin; /iiinerve-ending. Methylenblue preparation, after Zawarsin. disc of strong chitin of yellow colour (d), and connected with a canal {en) carrying a fine nerve-ending {nc). Some of these organs are also found on the surface of the labrum itself. The epipharynx also carries two stiff brushes of hairs (fig. 67, br) pointing inwards. Numerous small scattered tactile hairs occur both on the labrum and epipharynx, and a row of strong hairs along the border of the former organ. The Hypopharynx (fig. 69). The hypopharynx (fig. 69) is well-developed in Dragonflies. It is a soft chitinous outgrowth from the base of the labium, projecting into the buccal cavity in the form of a distinct tongue. It is usually regarded as an organ of taste. It is, however, covered only with numerous long yellow hairs. Zawarsin [204] has shewn that the nerve-supply of these hairs is of the ordinary kind. He therefore concludes that the hypopharynx is merely an organ of touch in the larva. We think the same holds good for the imago. The opening of the salivary ducts lies at the base of the hypopharynx (fig. 45 e).. 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
Size: 1760px × 1420px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishercambridgeenguniver
