3i4i MOTIONS OF INSECTS. 



sent of only one coleopterous insect that has them (Z>y- 

 tiscus marginalis). They are placed under the ely- 

 tra at their base. Their use is unknown ; but it may 

 probably be connected with their flight. The wings 

 of beetles* are usually very ample, often of a substance 

 between parchment and membrane. 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, Atractocerns, Neci/dalis, and some other 

 genera — they are folded transversely under the elytra, 

 generally near the middle, with a lateral longitudinal 

 fold, but occasionally near the extremity ^. When they 

 prepare for flight, their antennae being set out, the ely- 

 tra 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 or- 

 gans, the elytra all the while remaining immoveable. 

 During their flight the bodies of insects of this order, 

 as far as I have observed them, are always in a position 

 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 

 bodies, and that the muscular apparatus that moves 

 them is deficient in force. In consequence of which, he 

 observes, they take flight with difficulty, and fly very 



' Plate X. Fig. 4. 



^ In Plate XXIII. Fig. .5. tlie wings of Dt/tiscm marginalis arc 

 represented as they appear when folded. 



