THE FORE LEGS. 
105 
stomach ; (see fig. 4,) and so tenaciously do they adhere, 
that the hook will break before they leave their hold. 
There these pests contrive to locate during the whole winter, 
and to the end of the following spring, feeding on the 
mucus ; by which time they have grown to full size, (fig. 5,) 
and must now undergo a new transformation; they quit 
their hold of the coating of the stomach, are carried into the 
villous portion along with food, from thence pass into the 
intestinal canal along with the chyme, and at length are 
discharged with it. The caterpillars thus evacuated seek 
an appropriate place in the ground, where they assume 
the imago or chrysalis condition ; and remaining in this 
state for some weeks, at length break out from their swathing 
and assume the form of the perfect insect. Immediately 
after this the males and females pair ; the latter becoming 
impregnated, set about seeking an appropriate situation where 
to deposit their eggs, which, in imitation of the parent, by a 
peculiar instinct, they fix on the hairs of a horse, from whence 
they are licked off and swallowed in the larva state. 
There are two species of gad-flies, the second is known 
by the name of the red bot, fig. 6 is its larva, and fig. 7 the 
perfect fly. Their natural history and habits are similar 
in all respects to the other. 
CHAPTER V. 
DISORDERS OF THE EXTERNAL PARTS OF THE HORSE. 
SECTION L— The,Fore Legs. 
We come now to treat of those portions of the frame of a 
horse most intimately connected with his action, and his 
