Microscopical Essays, 



The under, or more tranfp.arent wings of beetles excite out 

 attention even more than the upper, or cruftaceous ones; for 

 whether we confider the delicacy of their texture, the great 

 weight that many of them are calculated to fuftain in the air, or 

 the very curious manner in which they fold them up under the 

 upper cafe, their mechanifm muft aftonifh and delight us ; no 

 two genera will be found alike, 1 though every individual of the 

 fame genus will be exacl ; the wing of the forficula, or earwig, 

 Plate XIX. Fig. l, is an elegant fpecimen of the manner of their 

 folding ; this .wing folds under a cafe not one-eighth of it's fize. 



The under wing of the blatta orientalis, a beetle common in 

 moft kitchens, appears to unite the elytra and tranfparent wings, 

 partaking in fome degree of both. 



Among the membranaceous or more tranfparent-winged in- 

 fers, the variety is end lefs, each genus difTering effentially from 

 the other, fome appearing full of membranes, or nerves, curioufly 

 difpofe'd; others, again, with icarce any, like a clear piece of 

 talc, Or ifmglafs ; fome exhibit a curious ground-work of points, 

 which, on clofe examination, prove fhort hairs, while the nerves 

 of others are furnifhed with little fcales, or feathers, as in fome 

 fpecies of the gnat. The wings of many mufcae are coloured 

 with black, brown, and white, in clouds, fpots, ftripes, &c. &c. 



The libellulae, or dragon-flies, alone afford a great variety, not 

 only in form, but colour; thefe are all furnitlied with numerous 

 and very ftrong nerves, adapted to the velocity of their flight ; 

 the wings of the ephemera, or May flies, are much more delicate, 



thefe 



