There is one insect to which attention may be drawn, as affording a most striking example of speed among lowly-winged creatures. That is the dragon-fly. I have frequently had an opportunity of dropping into company with the largest species (_Libellula grandis_), in its aerial excursions in autumn by a particular roadside, along which there was a rushy-margined pool. At such times the writer has been occasionally on foot,--more frequently driving. On foot one has scarcely any means of judging of its speed, for in a moment it is past and gone out of sight. But what is the experience when you are driving, say at ten or twelve miles an hour? This rapid voyager passes over, proceeds beyond you almost out of sight, then turns, swerving widely from right to left, repasses again in both directions, traversing repeatedly the ground, while you are travelling, or rather dragging, over the same space of about a mile only once. We are apt to exaggerate in these matters, but with every allowance, having compared the flight of a dragon-fly with that of a passing hawk, swallow, or cuckoo, I have computed that this large species is capable of flying at a speed of from eighty to one hundred miles an hour--an enormous draw upon the creature's nerves and muscular powers, as manifested by occasional rests of a few minutes upon a bush or a piece of sedge, its habits not requiring uninterrupted flight at such a pace. Perhaps the need of these occasional rests is an erroneous opinion founded upon too limited an area of observation. For Cuvier has stated that M. Poey, who had particularly studied the insects of Cuba, informed him that at certain seasons of the year the northerly winds bring to the city of Havannah and its neighbourhood an innumerable quantity of specimens of one of the species of _Libellulæ_. Other instances of the periodical flights or migrations of dragon-flies have been noted by observers. And even butterflies have been seen to migrate to distant points of land, making flights of fifty or sixty miles across water. These long journeys may be relieved by occasional rests, as Mr. Newman and others have ascertained that lepidopterous insects are able to alight upon the water, rest awhile, and then rise with apparent ease--a fact readily credited by fishermen, who so frequently see the green-and-grey drake and other _ephemeræ_ float down stream, and, if not taken by the trout, suddenly spring up again, and resume their aerial dances. But this power of rapid movement in the dragonfly, be the rate more or less, is in just keeping with its structure. The insect's body is slender, the chest strongly developed, though firm; the wings, four in number, are narrow, of great length, and consist of fine, thin, dry membrane, stretched upon a series of lightly made _costæ_, or rafters. No wonder, then, that with such a mechanism the creature pursues its prey of smaller insects with such rapidity.