PLATE XX. FIG. 2.
Another Foot of a Fly
THIS shews us only the Bottom Joint of the Foot, with the Talons having their
hooked Point B C extended,
and the Spunges d e bending inwards, in order to
take hold of any Thing. We see also more plainly in this Figure the Joints whereby
the Talons perform their Motions.
The Foot is likewise shaded with a Growth of Hairs, which like a Brush serves to
clean the Fly's Wings and Eyes, an Office she employs it in very frequently. And indeed
it is a pretty Amusement to see her perform this Exercise; for first she cleans her Brushes,
by rubbing her Paws one against another, then draws them over her Wings, and after-
wards under them ; and at last concludes with brushing her Eyes and Head : by which
means she cleans away all little Particles of Dust or Smoke, that may cloud her Eyes,
or settle on her Wings.
PLATE XX. FIG. 3.
Part of a Fly's Eye
THIS little Piece of the pearled Eye of a Fly, consisting of nineteen Pearls or He-
mispheres (a particular Description whereof will be given in the next Plate) is here
introduced,
as it appeared before the Microscope, to shew how perfectly the Images of
Objects are reflected from their smooth and polished Surfaces, insomuch that Houses,
Trees, and Landscapes of every Thing within a certain Distance, may be discovered on
them, in the same manner as on the small Balls of Quicksilver, but not near so lively.
The Reflection from these being somewhat languid, as it is from Water, Glass, Chrystal,
and such-like Bodies.
The Image of two Windows in the Chamber where they were examined, is expressed
on each of these. More will be said in the next Plate concerning the Eyes of Insects.
PLATE XX. FIG. 2.
Part of a Fly's Wing
A Whole Wing (of which this is only a Part) is exhibited Plate XXII. Fig. 2. to ex-
press its Form in general.
But the Piece here before us is magnified a great deal
more, to afford a clearer Notion of its wonderful Structure and Materials.
It consists plainly of a fine thin transparent Skin or Membrane, variously folded, plat-
ted and distended over the whole Area ; and several Bones, Ribs, or Stems, disposed
with great Regularity and Contrivance, so as to strengthen and support the Wing, and de-
termine its proper Figure.
A B, C D, E. F, are the Bones or Ribs of the Wing ; each of which is manifestly
covered with Multitudes of little Scales ; and A B, in particular, which is the largest Bone
of the whole Wing, and may properly enough be called the Cut-Air, being that which
terminates and stiffens the foremost Edge of the Wing, is not only covered with Scales ly-
ing regularly one over another ; but its Fore-Edge is armed with great Numbers of little
Bristles, all the Points of which are directed towards the Tip of the Wing: And even
the whole Edge all round the Wing is covered with a small Fringe, consisting of shorter
and more slender Bristles.
G H, I K, The fine Membrane extended between these bony Ribs, if examined by
the first or second Magnifier, and in a clear and proper Light, will be seen thickly stuck
with innumerable minute sharp-pointed Hairs or Bristles, ranged in the most regular Rows,
over its whole Surface; and intermingled with these may be perceived a like Number of
little Pits or black Spots, which seem to be the Roots of the Hairs growing on the other
Side.
In several other Flies, there are infinite Numbers of small Fibres which cover both
Sides of this thin Membrane, instead of minute Hairs : And on most Moths and Butter-
flies, they don't only resemble the Feathers of Birds in the Manner of their Arrange-
ment, but are variegated with the same kind of curious and lively Colours which the
Feathers of Birds exhibit.
