348 MOTIONS Ob l.NSKCTS. 



leopiera or beetles. Their subsidifiry instruments ot* 

 flight are their wing-cases (JE/j/fra), and in one instance, 

 winglets {JJidm). The former" — which in some are of 

 a hard horny substance, and in others are softer and 

 more like leather, though they are kept immovable in 

 flight, are probably, by their resistance to the air, not 

 without their use on this 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 coleopterous insect that has 

 them {Di/tisciis jnarginalis, 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 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, Artractocerus, Neci/dalis, and 

 some other genera — they are folded transversely under 

 the elytra, generally near tlie middle, with a lateral 

 longitudinal fold, but occasionally near the extremity*^. 

 When they prepare for flight,- their antennae 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 niotion of 

 these organs, the elytra all the while remaining im- 

 moveable. During theirflight the bodies of insects of 



» Plate X. Fig. 1. " Plate XXI IT. Fig. 6. a. ' Plate X. Fig. :. 

 '' In Plate XXllI. Fig. 5. the wings of Di/liscus inarginatis are re- 

 presented as tbey appear when folded. 



