36 NAKED WINGS. 



Now, every one must have noticed, that bees, flies, 

 and all insects which have membranous or naked wings, 

 must keep those wings constantly in rapid motion 

 while they fly. The motion is often so rapid that the 

 wings cannot be seen, any further than by a sort of 

 tremulous motion in the air ; and the action of the 

 wings produces all that humming and buzzing among 

 fl}iug insects, which makes the summer air so lively ; 

 for insects do not breathe by the mouth, and have no 

 organ of voice of any description. The action of 

 those naked wings upon the air must be very con- 

 siderable ; because when a common blue-bottle fly 

 (musca vondtoria) alights on the window, and marches 

 along one of the dusty bars of the frame, winnowing 

 the air with its wings, in a vain attempt to escape 

 through the glass, it stirs the dust more in proportion 

 than a coach and six driving rapidly along a dry 

 road on a hot summer's day. Insects with wings of 

 this description cannot hover, or lean on the air with 

 still and expanded wing. 



But the lepidoptera, especially the butterflies, do 

 hover about, and rest on the air, and wheel in various 

 directions, with very little apparent motion of the 

 wings ; and when they do move them, it is done 

 much more slowly than the motion of the naked 

 wing, in proportion to the rate of progressive motion. 

 These lepidopterous wings also move in silence, or 

 when they are brought into such rapid action as to 

 produce a sort of noise, it is a low and inuflied rustic, 

 and does not ring out, so that the largest butterfly or 

 moth gets along much more silently than the gnat. 

 We may add, as a farther instance of the same kind, 

 that the bats when they fly, are always obliged to 

 winnow the air with their flying membranes, some- 

 thing in the same way as naked winged insects do, 



