{108}"They have been variously named by different authors, owing perhaps to the time when they wrote, or the progress natural history had made in the world. Some have called them by the name of Dragon Fly, others Adder Bolt, Balance Fly, Perla, Libellula or Libella. I shall prefer the last, as conveying an idea well known to English adepts. The caterpillars of them all live in ponds and stagnant waters (that are undisturbed by cattle) during the greatest part of their lives, and make their appearance under three general forms. The first is shewn by Fig. 1. 1.; the second by Fig. 2.; and the third by Fig. 3. See Plate 47. As these are the shapes in which they all appear, it will not be improper to mention each particularly. "The two caterpillars at Fig. 1. 1. Plate 47, belong only to or produce those that sit at rest, with their wings erect, (see Plate 48. Fig. 2.), and differ from both the others not only in size but in the roundness and slenderness of their bodies; at the extremity whereof they are furnished with three tails, each of which upon examination being found to be a kind of feather, and is an appendage that neither of the others have. Their behaviour also in the water is different from the others, being enabled to twist and bend their bodies in a more circular manner. [Subfamily Agrionides.] "The second sort of caterpillars, at Plate 47. Fig. 2. are much shorter and thicker in their bodies than either of the others, producing those Libellas with flat bodies, as Plate 47. Fig. 4. and 6. and Plate 48. Fig. 1. and 5. These are, of all others, the most disagreeable in their appearance; most of them having their bodies and legs very rough and shaggy, and of the exact colour of mud. Others appear of a dirty green, and very unpleasing hue, a colour that in general reigns among them all; for none can boast of any beautiful appearance while in this state, unless the different shapes here exhibited can be called so. Indeed the beauty and symmetry, so apparent in their complete states, make ample amends for the want of it in this; all of them in general being then very beautiful, discovering colours superior to art. [Subfamily, Libellulides. Genus, Libellula.] "The caterpillars of the third sort (see Plate 47. Fig. 3.) are very different from the preceding, being the size of the figure, with the abdomen flat at bottom and rounding at top, longer and slenderer than those at Fig. 2. but not so much as those at Fig. 1. 1. These produce those large Libellas with long slender bodies, who sit at rest with their wings expanded, as Plate 47. Fig. 5. [Subfamily, Libellulides. Genus, Æshna.]