MUSCA. 89 



the observer with the utmost indifference. How 

 this operation is effected we are still at a loss 

 to determine. The foot of the fly, when highly 

 magnified, shows two hairy soles united at the 

 heel. These soles are flat, and are pressed upon 

 by the fly whenever it moves. The requisite 

 adhesion, which is obtained by the insect while 

 walking upon a polished and perpendicular sur- 

 face, has been referred to exhaustion; and 

 that, as in the suckers of the Remora, or Sepia, 

 a vacuum is formed, and the foot kept down by 

 the external pressure of the atmosphere : but 

 this conjecture will not hold, since we are as- 

 sured by Hooke, in his Micrographia, that 

 " they cannot make themselves so light as to stick 

 or suspend themselves on the under surface 

 of a glass well polish'd and cleans'd." 



SPECIFICATION. 



Muse a meridian a. M. antennis plumatis pilosa 



nigra, fronte aurata, alis basi luteis. Linn. Syst. 



Nat. 1. p. 989. Gmelp.2838. Fabr. Spec. Ins 2. 



^.435. Mant. Ins. 2. p. 342. Ent, Syst. 4. p. 312. 



Reaum* Ins. 4. t. 26./. 10. 



I 3 



