56 ELEMENTS OF ENTOMOLOGY. 



clearly exemplified in that description of wings which is usually term- 

 ed transparent, as in the common house-fly and the bee. The true 

 ving, by means of which the insect is enabled to fly, is always con- 

 structed in this mamier, whatever may be its appearance externally, 

 arising from a superficial covering of down, feathers, hair, or any other 

 cause. The variety in the form and structure of the wings, in the 

 number, figure, and disposition of the ner\'ures, or the colours witli which 

 they are adorned, is infinite. The diversity in the disposition of the 

 nervure is evident from a comparison of the simply constructed wing of 

 the common house-Hy with the complex wing of the Panorpa or the 

 Hiphemera, or the wings of an earwig, which consists of a series of sin- 

 gle nervure, with theelaborately wrought lattice-work of the wing of the 

 Libcllula. The whole of the U^pidoptcrous order exhibit the sui)erficial 

 coating of feathers, down, or hairs j and upon the removal of these the 

 wings are found constructed in the same manner as the transparent 

 vings of the other orders. A variation in the form of the wing as well 

 as its texture is manifest throughout all insects of the winged kind. 

 Those of the CoUoptcrn have two membranaceous wings, which fold 

 upon each other, iurming a jdait or double at their external margin, 

 which fold is accommodated by a peculiar joint in the main rib of 

 the wing, and the disposition of theuer\ures in the middle of the wing 

 contiguous. In the Hemiptcru the wings generally fold longiUidinally, 

 without any transverse double ; so that in expansion these parts open 

 somewhat like a fan. The anterior wings of the Lepidoptera are neither 

 doubled across nor folded longitudinidly ; tliey are entirely flat, and 

 are but little caj)able of contraction and dilatation. In the genus Pa- 

 pilio they are endowed with the power of erection, which is rarely the 

 case in the Phahencc, though occasionally observed among the Sphin- 

 ges; the FhahcTKE have the lower wings concealed imder the anterior 

 pair, the latter being laid in a flat position over them. The wings of 

 the Lepidoptera are downy, and oft(;n decorated with very beautifiil 

 colours disposed in the most pleasing and varied manner. The Heu- 

 Toptcra in general have the wings flat; this is not invariable; they are 

 constantly membranaceous, and reticulated with ner^-ures. In the 

 Hijmcnoptcra the wings are membranaceous, generally flat, but some- 

 times folded when the insect settles, as in the wasp genus. The Dipte- 

 rous order cannot be confounded with the preceding, as they have only 

 two wings : they are membranaceous as in the former. 



In all insects of the winged kind these organs present the greatest 

 diversity, and aftbrd characters both for genera and species less liable 

 to iluctuation tlian common observers would conceive. The number, 

 figure, construction, proportion, consistence, and texture of the wings 

 have enabled naturalists to distribute insects into principal groups 

 with considerable precision. Linae derived much assistance from an 



