130 EVENINGS AT THE MICEOSCOPE. 



strange, I approaclied it, and found that it was making 

 violent contortions, as thougli every leg were affected 

 with St. Vitus' dance, in order to pull its pulvilli from 

 the surface of the glass, to which they adhered so 

 strongly that though it could drag them a little way, 

 or sometimes by a violent effort get first one and then 

 another detached, yet the moment they were placed on 

 the glass again, they adhered as if their under side 

 were smeared with bird-lime. Once it succeeded in 

 dragging off its two fore, legs, when it immediately 

 began to rub the pulvilli against the tarsal brushes ; 

 but on replacing them on the glass they adhered as 

 closely as before, and it was only by efforts almost con- 

 vulsive, and which seemed to threaten to pull off its 

 limbs from its body, that it could succeed in moving a 

 quarter of an inch at a time. After watching it with 

 much interest for five minutes, it at last by its con- 

 tinued exertions got its feet released and flew away, 

 and alighted on a curtain, on which it walked quite 

 briskly, but soon again flew back to the window, where 

 it had precisely the same difficulty in pulling its pul- 

 villi from the glass as before ; but after observing it 

 some time, and at last trying to catch it, that I might 

 examine its feet with a lens, it seemed by a vigorous 

 effort to regain its powers, and ran quite actively on 

 the glass, and then flying away I lost sight of it. I am 

 unable to give any satisfactory solution of this singular 

 fact. The season, and the fly's final activity, preclude 

 the idea of its arising from cold or debility, to which 

 Mr. "White attributes the dragging of flies' legs at the 

 close of autumn. The pulvilli certainly had much 

 more the appearance of adhering to the glass by a vis- 

 cid material than by any pressure of the atmosphere. 



