• (n.) One of the minute cushions on the feet of certain insects.
(from the article `housefly`) ...however, does bite. The housefly can walk on vertical window panes or hang upside down on a ceiling probably because of the surface-tension ...
The little pad beneath each claw on the foot of a fly.
Pul·vil'lus noun ; plural Pulvilli . [ Latin , a little cushion.] (Zoology) One of the minute cushions on the feet of certain insects. 
a soft, padlike structure located at the base of each claw on the feet of certain insects.