. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. xix] AND BIOLOGICAL METHODS 359 At the fourth or fifth instar they should be transferred to larger "observation jars," and fed on water-fleas, or small mosquito-larvae. Only one species of larva should be kept in each jar. Later on they may be fed with larger mosquito-larvae, or small Agrionid larvae. Glass cells, either rectangular or cylindrical, make excellent observation jars (fig. 187). These should have a clean sandy bottom, with water-weeds growing therein. I find VaUisneria and Elodea the best forms for a
. The biology of dragonflies (Odonata or Paraneuroptera). Dragon-flies. xix] AND BIOLOGICAL METHODS 359 At the fourth or fifth instar they should be transferred to larger "observation jars," and fed on water-fleas, or small mosquito-larvae. Only one species of larva should be kept in each jar. Later on they may be fed with larger mosquito-larvae, or small Agrionid larvae. Glass cells, either rectangular or cylindrical, make excellent observation jars (fig. 187). These should have a clean sandy bottom, with water-weeds growing therein. I find VaUisneria and Elodea the best forms for aerating the water, particularly the former. The duck-weed (Lemna) and the pretty Azolla are also invaluable as surface weeds. A few sticks should be arranged so as to stand up some inches above water-level, for the larvae to climb up at metamorphosis. For bottom-dwelling larvae I use a small cii'cular tin pan (fig. 188), with. 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: 1346px × 1857px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishercambridgeenguniver
