116 



EVENINGS AT THE MICROSCOPE. 



Now it is evident that the bulbous extremities of these 

 soft filaments are the organs of adhesion. We notice how 

 they drag and hold, as the fly draws its foot from its 

 place ; and it seems almost certain that the adhesion is 

 effected by means of a glutinous secretion poured out in 

 minute quantities from these fleshy tips. When the foot 

 is suddenly removed, we may often see a number of tiny 

 particles of fluid left on the glass where the filaments had 

 been in contact with it : but I do not build conclusively 

 on this appearance, because the fly, having been confined 

 for some quarter of an hour in this nearly tight glass cell, 

 has doubtless exhaled some moisture, which has condensed 

 on the glass ; and the specks we see may possibly be due 

 to the filaments of the palms having become wet by re- 

 peatedly brushing the moist 

 surface. Mr. Hepworth, how- 

 ever, asserts that a fluid is 

 poured out from these fila- 

 ments, and is deposited on 

 the glass, when the fly is vi- 

 gorous, with great regularity. 

 He says that " when in a 

 partially dormant state, the 

 insect does not appear to be 

 able to give out this secretion, 

 though it can still attach it- 

 self : indeed, this fluid is not 

 essential for that purpose." * 

 It is asserted that the speckled 

 pattern of fluid left on the 

 glass by the fly's footsteps re- 

 mains (if breathed on) when 

 the moisture is evaporated ; 

 and hence it is presumed to be of an oily nature. 



In some Beetles the joints of the foot are furnished with 

 * " Micros. Journal" for April, 1854. 



FOOT OF FLT. 



