The situation assigned to this group of in sects by different systematists has varied con siderably. Many authors have placed them with the pentamerous insects, unto which from their habits and number of joints in their tarsi they appear to belong. Thus Dejean assigned them a position between the Hydrudephaga and l'hylkydrida ; Dr. Leach* between the Silphidee and Derracaide r; Mr. Kirby, in his recent work,-1- between the Adephoga and Necrophaga ; and, lastly, Mr. Westwood ! between the Dermestid& and Byrrhider. On the other hand Mr. Stephens, after Linn6 and Fabricius, has placed them at the end of his Coleoptera, thinking, probably, as Mr. Kirby has remarked, that they are connected with the following orders, Dermaptera and Orlhoplera, by their abbreviated elytra, and by their anal papillae or styles ; as they are also, probably, by the shortness and structure of their alimen tary canal, which in many respects as much resembles that of the Forficulidee or Blattidet, as the Adephaga or Necrophaga.
Order II. DER3IAPTERA.
Wings four, anterior ones (elytra) crustace ous, quadrate, and divided by a straight suture; not employed in flight ; posterior ones mem branous, folded longitudinally and transversely, only partially covered by the elytra ; anus armed with large moveable forceps. Larva active, resembles the perfect insect. Metamor phosis incomplete.
The single family of this order, Forficulider, (Earwigs) are readily distinguished from the Brachelytra by the fercipated anus, the great length of the antenna, and the breadth and circularity of the wings when expanded, com pared with the narrow and acute ones of the latter insects.
Order III. ORTHOPTERA.
Wings four, anterior ones coriaceous, reticu lated, and overlapping each other, posterior ones partly coriaccous partly membranous, re ticulated, and folded longitudinally; head ver tical ; mandibles, thick, strong, and dentated; palpi four, maxillary ones in most genera five jointed. Metamorphosis incomplete. The larva are active, and resemble the perfect insect.
In this Order are included many remarkable families. The Locustide, Locusts ; the Arlie lider, the House and Mole-crickets (fig. 342); Order IV. NEUROPTERA.
Wings four, linear, naked, membranaceous, and minutely reticulated ; all employed in flight ; head large, eyes projecting ; body linear.
This Order is divided into five sections.
In the first section, Panorpina, or Scorpion flies (fig. 344), the head is produced anteriorly into a short rostrum, at the extremity of which is the mouth, as in some of the Curculionide ; the antennae are long and filiform, and the body is slender, and terminates in the female in an acute ovipositor, and in the male in an articulated claw (a) like the tail of the Scor pion, from which the insect derives its name.
The larva is unknown, but is supposed to un dergo a complete metamorphosis. The pupa or nymph is inactive.* The perfect insect is predaceous.
In the second section, the Anisoptera or Ephe merider, May-flies (fig. 345), are distinguished the Manacle, or praying insects ; and the Blat tide (fig. 343), or destructive Cock-roaches.
by the smallness of their posterior wings, by the shortness of the antenna, and by the long seta at the extremity of the abdomen. The larva are active, and much resemble the perfect in sect. They reside constantly beneath stones, or in burrows at the bottom of running streams,t and undergo an incomplete metamorphosis. The pupa is active like the larva. In the per fect insect, which takes no food, and is prover bially noted for the shortness of its existence, which is seldom more than a few hours, the parts of the mouth are almost entirely oblite rated.
In the third section, Libellulina, Dragon flies, all the wings are of equal size, eyes large and prominent, antenna minute, body slender, and tarsi with only three joints. The larva and pupa are active, voracious, and aquatic, and like those of the Ephemera, resemble the per fect insect. Metamorphosis incomplete.
The fourth section, Termitina, have large and nearly equal sized wings, either disposed horizontally or erect, with the antenna rather long and filiform, as in Ilenierobide, lace winged flies, or club-shaped, as in the ant-lions, Illyrmelionide. The larva are active and pre daceous. The ant-lion lives at the bottom of a minute pit-fall, which it digs to entrap other insects. The Hernerobius lives among crowds of Aphides, plant-lice, upon which it feeds, while the larva of the Termites, or white ants, live in societies of almost innumerable indivi duals. The first two of these families undergo a complete metamorphosis, and the insects in the condition of nymphs are inactive in the earlier stages of the pupa state. In the latter family the larva and pupa greatly resemble the perfect insect, and are active at every period of existence.
The fifth section, Megaloptcra, have the pos terior wings rather larger than the anterior, the head and pro-thorax large and quadrate, and the antenna long and setaccous. Metamor phosis incomplete. According to Mr. West wood • the larva and pupa are active, and not inclosed in a case, are aquatic, and greatly re semble the perfect insect.