Page:The Book of the Aquarium and Water Cabinet.djvu/129

Rh anatomised this class of animals, and to him we are indebted for the microscopic anatomy of grubs, and a revelation of their inner economy generally.

, Libellulidæ; (Leach), a well-known summer beauty&mdash;the mere mention of which is always sufficient to set one&rsquo;s heart beating for rustic coolness, and the hushed music of the beechen shades&mdash;is, in its larva form, an interesting object for the cabinet. Between the larva and the imago of this insect, the difference is striking indeed; as a lady, not addicted to scientific studies, once characterised the larva&mdash;using Pope&rsquo;s lines&mdash;as,

But the gauze-winged and gaily-coloured fly merits all the praise bestowed upon it by the French, who call them Demoiselles, so light, fairy-like, and visionary are its form and movements. Scientific writers have applied many descriptive names to it, such as Calepteryx (pretty wing), Puella (girl), Sponsa (bride), and Virgo (virgin). The larva of the dragon fly exhibits, in a very striking manner, the mode of respiration in aquatic insects. It is not an active creature; for though it has six legs, it seldom uses these except in the capture of prey; its locomotion is chiefly performed by the tail in the action of breathing. When thrown into a jar with some fragments of weed and a few light chips, these will be seen to be drawn towards the tail of the creature, by the current occasioned by the absorption of water; and then again driven off, with