Those wings are termed plicatiles, which are folded when the insect is at rest, as in the wasp. Planæ; those which are incapable of being folded. Erectæ; whose superior surfaces are brought in contact when the insect is at rest, as in the ephemera, papiliones, &c. Patentes; if they are extended horizontally when the insect is at rest, as in the phalænæ geometræ. Incumbentes; those insects which, when they are not in motion, cover horizontally with their wings the superior part of the abdomen. Deflexæ; those are also incumbentes, but not horizontally, the outer edges declining towards the sides, Reversæ, are also deflexæ, with this addition, that the edges of the inferior wings project from under the anterior part of the superior ones. Dentatæ; with serrated or scolloped edges. Caudatæ; in these some of the fibres of the wings are extended beyond the margin into a kind of tail. Reticulatæ; when the veins or membranes of the wings put on the appearance of net-work.
The wings are further distinguished by their ornaments, being painted with spots, maculæ; bands, fasciæ; streaks, strigæ: when these are extended lengthways, they are called lines, linæ; and if with dots, punctæ; one or more rings are termed eyes, ocelli; if the spots are shaped like a kidney, they are termed stigmata.
The elytra, or crustaceous cases of the wings are extended when the insect flies, and shut when it rests, forming a longitudinal suture down the middle of the back; they are of various shapes, and distinguished by the following names:
Abbreviata; when they are shorter than the abdomen. Truncata; when their extremities terminate in a transverse direct line. Fastigiata; when of equal or greater length than the abdomen, and terminating in a transverse line. Serrata; having their external margins edged with teeth or notches. Spinosa; when their exterior surfaces are covered with small sharp points. Scabra; when they are very rough. Striata; marked with slender longitudinal furrows. Porcata; having sharp longitudinal ridges. Sulcata; with deep furrows. They are likewise distinguished by the denomination of Hemelytra, when their cases are neither so hard as the elytra, nor so delicate as the transparent wings.
OF THE HALTERES OR POISERS OF INSECTS.
Under the wings of most insects which have only two, there is a small head placed on a stalk, frequently under a little arched scale; these are called halteres, poisers; they appear to be rudiments of the hinder wings: it has been supposed that they serve to keep the body in equilibrio when the insect is flying.
OF THE ELYTRA, AND WINGS UNDER THE ELYTRA.
I have already observed, that the delicate and transparent wings of many insects are covered and protected by elytra, or cases, which also in some measure act as wings.
These exterior cases are harder and more opake than the wings under them; they are generally highly polished, and often enriched with various colours, adorned with ornamental flutings, and studded with brilliants, whose beauties are beyond description. All these ornaments are united in the curculio imperialis,[56] or diamond beetle, one of the richest and most magnificent creatures in nature; the head, the wings, the legs, &c. are curiously beset with scales of a most splendid appearance, outvying the ruby, saphire, and emerald, forming in miniature one of the most noble phenomena that the colours of light can exhibit. It is said, that in the Brazils, from whence they come, it is almost impossible to look at them on a sunny day, when they are flying in little swarms, so great is the glowing splendor of their heightened colours.
[56] Fabriciús Spec. Ins. 184. 129.—Drury. Ins. 2 Tab. 33, Fig. 1.