348 MOTICNS OF INSECTS. 
occasion. The winglets are small concavo-convex scales, 
of a stiff membranaceous substance, generally fringed at 
their extremity?. I know at present of only one cole- 
opterous insect that has them (Dytiscus marginalis, L.). 
They are placed under the elytra at their base. ‘Their 
use is unknown; but it may probably be connected with 
their flight. The wings of beetles? are usually very am- 
ple, often of a substance between parchment and mem- 
brane. The nervures that traverse and extend them, 
though not numerous, are stronger and larger than those 
in the wings of insects of the other orders, and are so 
dispersed as to give perfect tension to the organ. When 
at rest—except in Molorchus, Artractocerus, Necydalis, 
and some other genera—they are folded transversely un- 
der the elytra, generally near the middle, with a lateral 
longitudinal fold, but occasionally near the extremity. 
When they prepare for flight, their antenne being set, 
out, the elytra are opened so as to form an angle with 
the body and admit the free play of the wings, and they 
then fly off, striking the air by the vertical motion of 
these organs, the elytra all the while remaining immove- 
able. During their flight the bodies of insects of this or- 
der, as far as I have observed them, are always in a po- 
sition nearly vertical, which gives to the larger sorts, the 
stag-beetle for instance, a very singular appearance. 
Olivier, probably having some of the larger and heavier 
beetles in his eye, affirms that the wings of insects of this 
order are not usually proportioned to the weight of their 
4 Prater XXIII. Fie. 6. a. 
b Prater X. Fie. 4. 
¢ Jn Prare XXIIT. Fic. 5. the wings of Diyliscus marginatis are re- 
presented as they appear when folded. 
