Def. Metamorphosis semicomplete.
Elytra coriaceous, without veins, united by a straight suture, so as partly to cover the wings.
Wings longitudinally and transversely folded, each forming nearly the quadrant of a circle: neuration radiating[1178].
Anus forcipate.
4. Orthoptera[1179] (Ulonota F.). This Order, which Linné at first regarded as belonging to the Coleoptera[1180], and afterwards improperly added to the suctorious Hemiptera, was very judiciously separated from both by De Geer, under the name of Dermaptera, a name not improper, and which ought to have been retained. Its present name was, I believe, assigned to it by Olivier; and as this is generally in use, I shall not attempt to disturb it. Dr. Leach divided the Order into two, separating the Blattina from it, under the name of Dictyoptera[1181]. He was led to this by the tegmina decussating or lapping obliquely over each other, whereas in the rest the horizontal portion of one tegmen lies longitudinally over that of the other; he also probably took their depressed body into consideration;—these circumstances, however, rather indicate a tribe or suborder; and as such Mr. MacLeay regards it.
Def. Metamorphosis semicomplete.
Legs suspended.
Tegmina generally pergameneous[1182], reticulated with nervures, more or less incumbent, covering the wings.
Wings longitudinally folded, ample: neuration reticulated.
5. Neuroptera[1183] (Synistata, Odonota F.). Of all the Linnean Orders this appears to consist of the most discordant tribes; so that it seems next to impossible to construct a definition that will include them all, unless indeed we admit M. Latreille's idea, adopted by Mr. MacLeay[1184], that a varied metamorphosis is its essential character; or, to speak more largely, variety itself seems the characteristic of the insects composing it, in every state; and there is scarcely a common distinctive character in their perfect state, upon detecting which in any individual you may exclaim—This is a Neuropterous insect. The only one that I have been enabled to seize is, that their scapulæ and parapleuræ are parallel and placed obliquely[1185]. Whether, with all this puzzling variation and dissonance between the different tribes of which it is now composed, this Order can be considered as a natural group, in the present state of our knowledge it would be rash to decide. I shall observe, however, that the Libellulina,—whether we regard their metamorphosis and the singular character before described that distinguishes their larva and pupa[1186], their oral instruments[1187], the remarkable position of their legs[1188], their general form, the wonderful and peculiar machinery by which their wings are moved[1189], and other circumstances of their internal anatomy,—if any are to be regarded as forming a separate Order, are the first entitled to that distinction. At present, with our friend Mr. MacLeay, I shall consider it as not further divisible, and as consisting of five principal forms. I must not omit to observe, that in the Ephemerina the parts of the mouth, except the labrum and palpi, appear to be mere rudiments[1190].