40 HU/ OF FLIttS. 



"in keeping" on an atmospheric line, a principal agent in 

 their flight, as well as in that of other Insects, being the air. 

 This enters from the breathing organs of their bodies into the 

 nerves and muscles of their wings; from which arrangement, 

 their velocity depends, not alone on muscular power, but 

 also on the state of the atmosphere. 



How does a Fly 1m/ ? is another question more easily asked 

 than answered. "AYith its wings to be sure/ 1 hastily replies 

 one. of our readers; "with its wings as they vibrate upon the 

 air," responds another with a smile, half of contempt, half of 

 complacency at his more than common measure of Natural 

 Philosophy. But how then, let us ask, can the Great Dragon- 

 Fly and other similar broad-pinioned, rapid-flying Insects, 

 cut through the air with silent swiftness, while others go on 

 buzzing when not upon the wing at all? Rennie who has 

 already put this piling query,* himself ascribes the sound 

 partly to air, but to air as it plays "on the edges of the wings 

 at their origin, as with an Eolian harp-string," or to the friction 

 of some internal organ on the roots of the wing's nervures. 



Lastly, how does the Fly feed? the "busy curious thirsty 

 Fly" that "drinks with me," but does not "drink as I," 

 his sole instrument for eating and drinking being his trunk 

 or sucker, the narrow pipe, by means of which, when let 

 down upon his dainties, he is enabled to imbibe as much as 

 suits his capacity. This trunk might seem an instrument 



* Insect Miscellanies, p. 91. 



