46*8 
FLY. 
The eyes, like those of beetles and dragon-flies, are 
constructed in a very peculiar manner. They are 
two little hemispheres, perfectly immoveable, and 
occupying a large portion of the insect’s head. Each 
of these hemispheres contains a prodigious number 
of minute eyes arranged in a regular order by the 
side of each other, so that the whole assemblage ap- 
pears like lattice-work. Each of these minute 
specks is a perfect eye, and may be plainly seen 
when properly magnified by a compound micro- 
scope. By this contrivance the fly is enabled to see 
on all sides. The eyes of other creatures (if we 
may use the expression) are multiplied by motion ; 
whereas those of a fly are fixed and immoveable, 
consequently without this arrangement the animal 
could only see in one direction ; as it is, she is en- 
abled to see every thing in which she can be inter- 
ested. She has a number of enemies, but she has 
more than an eye for each, and can discover what- 
ever danger threatens her from above, behind, or on 
either side, even when she is in full pursuit of a prey 
directly before her. 
We observe seven or eight articulations in the 
leg of a fly, besides two bending claws, and several 
minute points on each of its paws : above all, we 
ought to notice the singular little sponges at the 
bottom of the feet placed at the juncture of its 
claws. Naturalists have supposed that, when this 
animal marches over any polished body on which 
neither her claws nor points can fasten, she some- 
times compresses her sponge, and causes it to eva- 
