Page:Jardine Naturalist's library Entomology.djvu/256

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250
SYSTEMATIC ARRANGEMENT.

in Surinam, and other parts of America, as well as in Africa and Asia. In some of them the tegmina and wings are of great amplitude, and the powers of flight are probably considerable; they are likewise ornamented with rich colours, frequently rendering them very ornamental objects. The similitude, of these parts, to the leaves of trees, formerly mentioned as signalising the Orthopterous order, is also conspicuous in the present tribe, particularly in that section of it, which, in allusion to this very circumstance, Kirby has proposed to name Pterophylla, or leaf-wings.

Grasshoppers deposit their eggs in the earth, an operation which they accomplish by means of the lengthened ovipositor, which forms one of their distinctive features. This instrument is slightly modified in form in the different genera. In Acrida, it consists of six pieces or valves, two upper and four lower, each of which is grooved internally, and these are moved backwards and forwards alternately, when employed in boring. The eggs are rather long, and narrowed at both ends; they are laid in considerable quantities at a time, and extruded together along with a kind of mucous matter, which soon dries and becomes a slender membranous envelope. The nymph or pupa does not differ from the larva, except in bearing on the back a pair of rudimentary wings, enclosed in a kind of sheath. The larvæ and pupa are, of course, incapable of flight, but the mature insect springs into the air with great facility, and expanding its capacious wings, can sustain itself for a