s_._

The foot of a Fly (delineated in the first _Figure_ of the 23. _Scheme_,
which represents three joints, the two Tallons, and the two Pattens in a
flat posture; and in the second _Figure_ of the same _Scheme_, which
represents onely one joint, the Tallons and Pattens in another posture) is
of a most admirable and curious contrivance, for by this the Flies are
inabled to walk against the sides of Glass, perpendicularly upwards, and to
contain themselves in that posture as long as they please; nay, to walk and
suspend themselves against the under surface of many bodies, as the ceiling
of a room, or the like, and this with as great a seeming facility and
firmness, as if they were a kind of _Antipodes_, and had a _tendency_
upwards, as we are sure they have the contrary, which they also evidently
discover, in 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; their suspension therefore is wholly to be ascrib'd to some
Mechanical contrivance in their feet; which, what it is, we shall in brief
explain, by shewing, that its Mechanism consists principally in two parts,
that is, first its two Claws, or Tallons, and secondly, two Palms, Pattens,
or Soles.

The two Tallons are very large, in proportion to the foot, and handsomly
shap'd in the manner describ'd in the _Figures_, by AB, and AC, the bigger
part of them from A to _dd_, is all hairy, or brisled, but toward the top,
at C and B smooth, the tops or points, which seem very sharp turning
downwards and inwards, are each of them mov'd on a joint at A, by which the
Fly is able to open or shut them at pleasure, so that the points B and C
being entered in any pores, and the Fly endeavouring to shut them, the
Claws not onely draw one against another, and so fasten each other, but
they draw the whole foot, GGADD forward, so that on a soft footing, the
tenters or points GGGG, (whereof a Fly has about ten in each foot, to wit,
two in every joint) run into the pores, if they find any, or at least make
their way; and this is sensible to the naked eye, in the feet of a
_Chafer_, which, if he be suffer'd to creep over the hand, or any other
part of the skin of ones body, does make his steps as sensible to the touch
as the sight.

But this contrivance, as it often fails the _Chafer_, when he walks on hard
and close bodies, so would it also our Fly, though he be a much lesser, and
nimbler creature,